WorldWideScience

Sample records for reinforced prefabricated walls

  1. Load-carrying capacity of lightly reinforced, prefabricated walls of lightweight aggregate concrete with open structure

    DEFF Research Database (Denmark)

    Goltermann, Per

    2009-01-01

    The paper presents and evaluates the results of a coordinated testing of prefabricated, lightly reinforced walls of lightweight aggregate concrete with open structure. The coordinated testing covers all wall productions in Denmark and will therefore provide a representative assessment...

  2. Critical Points of Prefabricated Reinforced Concrete Wall Systems of Multi-storey Buildings

    OpenAIRE

    J. Witzany; T. Čejka; R. Zigler

    2011-01-01

    With respect to the dissipation of energy through plastic deformation of joints of prefabricated wall units, the paper points out the principal importance of efficient reinforcement of the prefabricated system at its joints. The method, quality and amount of reinforcement are essential for reaching the necessary degree of joint ductility. The paper presents partial results of experimental research of vertical joints of prefabricated units exposed to monotonously rising lo...

  3. Quasi-static cyclic tests of two prefabricated, reinforced masonry walls

    OpenAIRE

    Braun, Bernard; Rupf, Michael; Beyer, Katrin; Dazio, Alessandro

    2010-01-01

    In the second half of the 20th century, the majority of residential buildings in Switzerland have been built with unreinforced brick masonry walls and reinforced concrete floors. Following a re-evaluation of the seismic hazard in Switzerland, a country of moderate seismicity, the seismic design spectra have increased in the last revision (2003) of the Swiss building code. As a consequence, it has become very difficult to justify the use of unreinforced masonry walls as sufficient seismic resi...

  4. Research Status on Bonding Behavior of Prefabricated Concrete Shear Wall

    Science.gov (United States)

    Wang, Donghui; Liu, Xudong; Wang, Sheng; Li, Shanshan

    2018-03-01

    Prefabricated shear wall structure adapts to the development and requirements of China’s residential industrialization. The key to the prefabricated concrete shear wall structure is the connection between the prefabricated members, where the reliability of the connection of the concrete joint is related to the overall performance and seismic effect of the structure. In this paper, the microstructures of the joint surface and shear properties are analysed, and the formula for calculating the shear strength of the joint is obtained.

  5. New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs

    OpenAIRE

    Real-Herráiz, Julia; Zamorano-Martín, Clara; Real-Herráiz, Teresa; Morales-Ivorra, Silvia

    2016-01-01

    [EN] Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of...

  6. Disperse reinforced concrete used in obtaining prefabricated elements for roads

    Directory of Open Access Journals (Sweden)

    Bogdan MEZEI

    2014-07-01

    Full Text Available Concrete is the most used material in construction. By improving the performance of materials and of technologies, concretes with outstanding performances were also developed, in the past two decades. Concrete with dispersed reinforcement represents a new generation of reinforced concrete that combines a good behavior of concrete compressive strength with an increased tensile strength of steel fibers. Using this material, monolithic and prefabricated concrete elements with high mechanical strengths and high durability can be obtained. Technological processes for preparation of concrete with dispersed reinforcement are similar to the conventional methods and do not involve using additional equipment for dosing the dispersed reinforcement. The study aimed the development of road plates made with optimized disperse- reinforced concrete. The first tests were done on plates from the gutter roadway, having a classic reinforcement, using different percentages of fibre reinforcement in the concrete composition, leading to the development of a new optimized economical solution. The results prove the enhanced characteristics of the disperse-reinforced concrete versus conventional concrete, and hence of the developed concrete plates.

  7. New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs

    Directory of Open Access Journals (Sweden)

    Julia Real-Herráiz

    Full Text Available Abstract Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of this solution is to guarantee a continuous and gradual track vertical stiffness transition in the vicinity of structures, overcoming granular wedges disadvantages. The aim of this study is to assess the performance of the novel wedge design by means of a 3-D FEM model and to compare it with the current solution.

  8. Prefabricated floor panels composed of fiber reinforced concrete and a steel substructure

    DEFF Research Database (Denmark)

    Lárusson, Lárus H.; Fischer, Gregor; Jönsson, Jeppe

    2013-01-01

    This paper reports on a study on prefabricated composite and modular floor deck panels composed of relatively thin fiber reinforced concrete slabs connected to steel substructures. The study focuses on the design, manufacturing, structural improvements and behavior of the floor systems during...

  9. In-Plane Strengthening Effect of Prefabricated Concrete Walls on Masonry Structures: Shaking Table Test

    OpenAIRE

    Li, Weiwei; Liu, Weiqing; Wang, Shuguang; Du, Dongsheng

    2017-01-01

    The improvement effect of a new strengthening strategy on dynamic action of masonry structure, by installing prefabricated concrete walls on the outer facades, is validated by shaking table test presented in this paper. We carried out dynamic tests of two geometrically identical five-story reduced scaled models, including an unstrengthened and a strengthened masonry model. The experimental analysis encompasses seismic performances such as cracking patterns, failure mechanisms, amplification f...

  10. Axial Compression Behavior of a New Type of Prefabricated Concrete Sandwich Wall Panel

    Science.gov (United States)

    Qun, Xie; Shuai, Wang; Chun, Liu

    2018-03-01

    A novel type of prefabricated concrete sandwich wall panel which could be used as a load-bearing structural element in buildings has been presented in this paper. Compared with the traditional sandwich panels, there are several typical characteristics for this wall system, including core columns confined by spiral stirrup along the cross-section of panel with 600mm spacing, precast foamed concrete block between two structural layers as internal insulation part, and a three-dimensional (3D) steel wire skeleton in each layer which is composed of two vertical steel wire meshes connected by horizontally short steel bar. All steel segments in the panel are automatically prefabricated in factory and then are assembled to form steel system in site. In order to investigate the structural behavior of this wall panel, two full-scale panels have been experimentally studied under axial compressive load. The test results show that the wall panel presents good load-bearing capacity and integral stiffness without out-of-plane flexural failure. Compared to the panel with planar steel wire mesh in concrete layer, the panel with 3D steel wire skeleton presents higher strength and better rigidity even in the condition of same steel ratio in panels which verifies that the 3D steel skeleton could greatly enhance the structural behavior of sandwich panel.

  11. Improving Thermal Insulation Properties for Prefabricated Wall Components Made Of Lightweight Aggregate Concrete with Open Structure

    Science.gov (United States)

    Abramski, Marcin

    2017-10-01

    Porous concrete is commonly used in civil engineering due to its good thermal insulation properties in comparison with normal concrete and high compression strength in comparison with other building materials. Reducing of the concrete density can be obviously obtained by using lightweight aggregate (e.g. pumice). The concrete density can be further minimized by using specially graded coarse aggregate and little-to-no fine aggregates. In this way a large number of air voids arise. The aggregate particles are coated by a cement paste and bonded together with it just in contact points. Such an extremely porous concrete, called ‘lightweight aggregate concrete with open structure’ (LAC), is used in some German plants to produce prefabricated wall components. They are used mainly in hall buildings, e.g. supermarkets. The need of improving thermal insulation properties was an inspiration for the prefabrication plant managers, engineers and a scientific staff of the Technical University of Kaiserslautern / Germany to realise an interesting project. Its aim was to reduce the heat transfer coefficient for the wall components. Three different wall structure types were designed and compared in full-scale laboratory tests with originally produced wall components in terms of load-carrying capacity and stiffness. The load was applied perpendicularly to the wall plane. As the components are not originally used for load-bearing walls, but for curtain walls only, the wind load is the main load for them. The wall components were tested in horizontal position and the load was applied vertically. Totally twelve wall components 8.00 × 2.00 × 0.25m (three for every series) were produced in the prefabrication plant and tested in the University of Kaiserslautern laboratory. The designed and tested components differed from each other in the amount of expanded polystyrene (EPS), which was placed in the plant inside the wall structure. The minimal amount of it was designed in the

  12. In-Plane Strengthening Effect of Prefabricated Concrete Walls on Masonry Structures: Shaking Table Test

    Directory of Open Access Journals (Sweden)

    Weiwei Li

    2017-01-01

    Full Text Available The improvement effect of a new strengthening strategy on dynamic action of masonry structure, by installing prefabricated concrete walls on the outer facades, is validated by shaking table test presented in this paper. We carried out dynamic tests of two geometrically identical five-story reduced scaled models, including an unstrengthened and a strengthened masonry model. The experimental analysis encompasses seismic performances such as cracking patterns, failure mechanisms, amplification factors of acceleration, and displacements. The results show that the strengthened masonry structure shows much more excellent seismic capacity when compared with the unstrengthened one.

  13. Prefabricated EPS Elements used as Strip Foundation of a Single-family House with a Double Brick Wall

    OpenAIRE

    Rasmussen, Torben Valdbjørn

    2008-01-01

    A new prefabricated lightweight element was designed for a strip foundation that was demonstrated on site as the base of a single-family house with a double brick wall. The element was placed on a stable surface underneath the top soil layer, just 0.25 m underneath the finished ground surface. The prefabricated element was designed to fulfil the requirements of low energy consumption required by the new Danish Building Regulations. The base of the house was cast in one working operation and c...

  14. Prefabricated EPS Elements used as Strip Foundation of a Single-family House with a Double Brick Wall

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    2008-01-01

    A new prefabricated lightweight element was designed for a strip foundation that was demonstrated on site as the base of a single-family house with a double brick wall. The element was placed on a stable surface underneath the top soil layer, just 0.25 m underneath the finished ground surface....... The prefabricated element was designed to fulfil the requirements of low energy consumption required by the new Danish Building Regulations. The base of the house was cast in one working operation and completed within two working days. The element, made of expanded polystyrene, was designed to be handled on site...

  15. Reinforced concrete wall under hydrogen detonation

    International Nuclear Information System (INIS)

    Saarenheimo, A.

    2000-11-01

    The structural integrity of a reinforced concrete wall in the BWR reactor building under hydrogen detonation conditions has been analysed. Of particular interest is whether the containment integrity can be jeopardised by an external hydrogen detonation. The load carrying capacity of a reinforced concrete wall was studied. The detonation pressure loads were estimated with computerised hand calculations assuming a direct initiation of detonation and applying the strong explosion theory. The results can be considered as rough and conservative estimates for the first shock pressure impact induced by a reflecting detonation wave. Structural integrity may be endangered due to slow pressurisation or dynamic impulse loads associated with local detonations. The static pressure following the passage of a shock front may be relatively high, thus this static or slowly decreasing pressure after a detonation may damage the structure severely. The mitigating effects of the opening of a door on pressure history and structural response were also studied. The non-linear behaviour of the wall was studied under detonations corresponding a detonable hydrogen mass of 0.5 kg and 1.428 kg. Non-linear finite element analyses of the reinforced concrete structure were carried out by the ABAQUS/Explicit program. The reinforcement and its non-linear material behaviour and the tensile cracking of concrete were modelled. Reinforcement was defined as layers of uniformly spaced reinforcing bars in shell elements. In these studies the surrounding structures of the non-linearly modelled reinforced concrete wall were modelled using idealised boundary conditions. Especially concrete cracking and yielding of the reinforcement was monitored during the numerical simulation. (au)

  16. Seismic evaluation of reinforced masonry walls

    International Nuclear Information System (INIS)

    Kelly, T.E.; Button, M.R.; Mayes, R.L.

    1984-01-01

    Masonry walls in operating nuclear plants are in many cases found to be overstressed in terms of allowable stresses when evaluated using current seismic design criteria. However, experimental evidence exists indicating that reinforced masonry walls have a considerable margin between the load levels at which allowable stresses are exceeded and the load levels at which structural distress and loss of function occurs. This paper presents a methodology which allows the actual capacity of reinforced masonry walls under seismic loading to be quantified. The methodology is based on the use of non-linear dynamic analyses and incorporates observed hysteretic behavior for both in-plane and out-of-plane response. Experimental data is used to develop response parameters and to validate the results predicted by the models. Criteria have been concurrently developed to evaluate the deformations and material performance in the walls to ensure adequate margins of safety for the required function. An example of the application of these procedures is provided

  17. Assessing corrosion of MSE wall reinforcement.

    Science.gov (United States)

    2010-09-01

    The primary objective of this study was to extract reinforcement coupons from select MSE walls and document the extent of corrosion. In doing this, a baseline has been established against which coupons extracted in the future can be compared. A secon...

  18. Seismic behavior of reinforced concrete shear walls

    International Nuclear Information System (INIS)

    Wang, F.; Gantenbein, F.

    1989-01-01

    Reinforced concrete shear walls have an important contribution to building stiffness. So, it is necessary to know their behavior under seismic loads. The ultimate behavior study of shear walls subjected to dynamic loadings includes: - a description of the nonlinear global model based on cyclic static tests, - nonlinear time history calculations for various forcing functions. The comparison of linear and nonlinear results shows important margins related to the ductility when the bandwidth of the forcing function is narrow and centred on the wall natural frequency

  19. Influence of facing vertical stiffness on reinforced soil wall design

    OpenAIRE

    Puig Damians, Ivan; Bathurst, Richard; Josa Garcia-Tornel, Alejandro; Lloret Morancho, Antonio

    2013-01-01

    Current design practices for reinforced soil walls typically ignore the influence of facing type and foundation compressibility on the magnitude and distribution of reinforcement loads in steel reinforced soil walls under operational conditions. In this paper, the effect of the facing vertical stiffness (due to elastomeric bearing pads placed in the horizontal joints between panels) on load capacity of steel reinforced soil walls is examined in a systematic manner using a numerical modelli...

  20. An Experimental and Analytical Study on perpendicular to plane Flexural behavior of New Prefabricated Wall Made by Extruded Polystyrene

    Directory of Open Access Journals (Sweden)

    Omid Rezayfar

    2017-07-01

    Full Text Available Nowadays softening of non-structural components as well as applying dry-wall systems are one of the efficacious measures to safe constructions against earthquakes. Using rigid and heavy non-structural elements, increase earthquake force and its destructive effects on the structure. Therefore, using flexible and light material in non-structural elements is one of the effective solutions to build light and safe structures against earthquakes. In this study, an experimental and analytical investigation on the behaviour of a new pre-fabricated wall made by extruded polystyrene, gypsum board and cement board has been studied through a comparative analysis that the following conclusions can be drawn. C-C Panels have 35% More resistance and G-G Panels have 37% more Plasticity. Thickness has positive effects on resistance and plasticity. Panels with thickness of 12.5cm have 37% more resistance and 21% more plasticity in comparison with panels with thickness of 7.5 cm.

  1. Pseudo-dynamic tests on masonry residential buildings seismically retrofitted by precast steel reinforced concrete walls

    Science.gov (United States)

    Li, Wenfeng; Wang, Tao; Chen, Xi; Zhong, Xiang; Pan, Peng

    2017-07-01

    A retrofitting technology using precast steel reinforced concrete (PSRC) panels is developed to improve the seismic performance of old masonry buildings. The PSRC panels are built up as an external PSRC wall system surrounding the existing masonry building. The PSRC walls are well connected to the existing masonry building, which provides enough confinement to effectively improve the ductility, strength, and stiffenss of old masonry structures. The PSRC panels are prefabricated in a factory, significantly reducing the situ work and associated construction time. To demonstrate the feasibility and mechanical effectivenss of the proposed retrofitting system, a full-scale five-story specimen was constructed. The retrofitting process was completed within five weeks with very limited indoor operation. The specimen was then tested in the lateral direction, which could potentially suffer sigifnicant damage in a large earthquake. The technical feasibility, construction workability, and seismic performance were thoroughly demonstrated by a full-scale specimen construction and pseudo-dynamic tests.

  2. Proposal for the award of a contract for the supply and installation of prefabricated reinforced-concrete modules for an LHC access shaft

    CERN Document Server

    2000-01-01

    This document concerns the award of a contract for the supply and installation of 33 prefabricated reinforced-concrete modules for the PX15 access shaft. Following a market survey carried out among 39 firms in fourteen Member States, a call for tenders (IT-2714/ST/LHC) was sent on 22 May 2000 to seven firms and one consortium consisting of four firms in seven Member States. By the closing date, CERN had received five tenders from four firms and one consortium in five Member States. The Finance Committee is invited to agree to the negotiation of a contract with the consortium JOINT VENTURE CCC (CH-DE-AT), the lowest bidder after realignment, for the supply and installation of prefabricated reinforced-concrete modules for the PX15 access shaft for a total amount of 988 915 Swiss francs, not subject to revision. The consortium has indicated the following distribution by country of the contract value covered by this adjudication proposal: DE-89%; CH-6%; AT-5%.

  3. Investigation of the possibilities of phosphogypsum application for building partitioning Walls - elements of a prefabricated house

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2002-01-01

    Full Text Available Phosphogypsum is a waste product in the manufacture of phosphoric acid from phosphorite and sulphuric acid by so-called "wet process" and represents a refuse that is as such simply thrown away. Phosphogypsum which is produced by "dihydrating procedure" contains not only various impurties but also radionuclides, which limits its construction use. Performed testings point to the complexity of phosphogypsum structure and composition while the electron microscope's pictures showed its different crystal composition compared to the natural gypsum. The calcined and refined phosphogypsum can be used for partition walls manufacture. To avoid the danger of the possible presence of radionuclides it is better to use the mixture of natural gypsum and phosphogypsum for this purpose. Substantial saving of materials and economic effect can be achieved in this way. The analyse performed in this work have shown significant presence of radionuclides in phosphogypsum. Gammaspectrometric measurements of radioactivity have determined substantial radioactivity of phosphogypsum. Using the maximum tolerated level values that are legally accepted, as well as equations to calculate indexes of tolerated radionuclide presence, an index of 2.23 has been determined for interiors and 1.13 for exteriors, i.e. 0.64 in case of roads. On the basis of the maximum tolerated level of radioactive building materials contamination (< 1, forbiden is the use of phosphogypsum in interiors, allowed (≈ 1 in exteriors and roads. The tests of heavy metal components in phosphogypsum have proved their presence in the amounts potentially producing consequences if present in closed spaces. That is conditioned by the phosphogypsum quantity, as well as by the area of space partitioned.

  4. Thin-walled reinforcement lattice structure for hollow CMC buckets

    Science.gov (United States)

    de Diego, Peter

    2017-06-27

    A hollow ceramic matrix composite (CMC) turbine bucket with an internal reinforcement lattice structure has improved vibration properties and stiffness. The lattice structure is formed of thin-walled plies made of CMC. The wall structures are arranged and located according to high stress areas within the hollow bucket. After the melt infiltration process, the mandrels melt away, leaving the wall structure to become the internal lattice reinforcement structure of the bucket.

  5. Reinforcement mechanism of multi-anchor wall with double wall facing

    Science.gov (United States)

    Suzuki, Kouta; Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo

    2017-10-01

    The reinforced soil wall has high seismic performance as generally known. However, the seismic behavior has not been clarified accurately yet, especially on multi-anchor wall with double wall facing. Indefinite behavior of reinforced soil wall during earthquake make us complicated in case with adopting to the abutment, because of arrangement of anchor plate as reinforcement often different according to the width of roads. In this study, a series of centrifuge model tests were carried out to investigate the reinforcement mechanism of multi anchor wall with double wall facing from the perspective of the vertical earth pressure. Several types of reinforce arrangement and rigid wall were applied in order to verify the arch function in the reinforced regions. The test results show unique behavior of vertical earth pressure, which was affected by arch action. All the vertical earth pressure placed behind facing panel, are larger than that of middle part between facing panel despite of friction between backfill and facing panel. Similar results were obtained in case using rigid wall. On the other hands, the vertical earth pressure, which were measured at the 3cm high from bottom of model container, shows larger than that of bottom. This results show the existence of arch action between double walls. In addition, it implies that the wall facing of such soil structure confined the backfill as pseudo wall, which is very reason that the multi anchor wall with double wall facing has high seismic performance.

  6. Prefabricated RM Façade Panels - Search for the Safe Solution

    Science.gov (United States)

    Hulimka, Jacek; Kubica, Jan; Kałuża, Marta; Galman, Iwona

    2017-10-01

    The problem, which appeared during the design works on the untypical masonry openwork of the front elevation of the academic building in Poland was presented and discussed in this paper. The original solution of masonry external façade was too risky and practically impossible for realization from the workmanship point of view. For this reason authors were proposed to make this elevation wall as prefabricated construction consisted of medium scale prefabricated elevation panels made of openwork clinker units and masonry joints with reinforcement. Two solutions of prefabricated panels were elaborated: first by the design office and second one, significantly modified, proposed by the authors. Taking into consideration fact that proposed prefabricated panels are not the typical reinforced masonry possible to design based on Eurocode 6, the methodology of “supporting design by test” was accepted to verify the correctness of proposed solutions. The carried out tests of both types of prefabricated panels with results and their discussion are also presented here. The results have shown the lack of safety for the first type of prefabricates and good behaviour, safety and durability of the final, modified solution.

  7. Maintenance and Durability of the Concrete External Layer of Curtain Walls in Prefabricated Technological Poznan Large Panel System

    Science.gov (United States)

    Jasiczak, Józef; Girus, Krzysztof

    2017-10-01

    The issue of usability and durability of large-panel building constructed several decades ago is a subject of an in-depth analysis of many domestic and foreign investments. When considering the durability of specific large-panel system, one should consider, among others, the process of making external walls. The long-term and direct impact of weather conditions on the external layer of curtain walls is significant for the durability of large-panel buildings. For the needs of the presented paper, in 2016, the survey of cracks and a series of other tests of large-panel façade, residential building constructed in 1986, in Poland, in the PLP process system - Rataje was executed. Several hundred large-size, triple-layer curtain-wall slab with a 6-cm, concrete exterior cladding layer anchored using pins and hangers with the load-bearing layer, a 9-cm insulation layer made of mineral wool, and a 21-cm structural layer were surveyed. Significant deviations in thicknesses of particular wall layers were proven. Other significant damages and defects of external layers were found. At the second stage, many tests, both nondestructive and destructive, were conducted. They involved determining mechanical properties of an external layer. The concrete thickness was measured using with a type N Schmidt sclerometer and core samples were taken from this layer in order to mark concrete’s compressive strength. The range of carbonation (by phenolphthalein method) and the actual location and condition of reinforcement were estimated using a ferromagnetic device to determine the condition of the external layer. The diagnosis conducted in such a manner was the verification of necessary repair of the walls and their thermal efficiency improvement while ensuring safe conditions of their operation and modern functional and utility requirements. It should be also emphasized that the method of diagnosing the external walls presented in this paper may be popularized when evaluating such

  8. Preliminary Analysis of Reinforced Concrete Waffle Walls

    National Research Council Canada - National Science Library

    Shugar, Theodore

    1997-01-01

    A preliminary analytical method based upon modified plate bending theory is offered for structural analysis of a promising new construction method for walls of small buildings and residential housing...

  9. Use of reinforced soil wall to support steam generator transfer

    International Nuclear Information System (INIS)

    Davie, J.R.; Wang, J.T.; Gladstone, R.A.

    1991-01-01

    Consumers Power Company had the two steam generators at its Palisades Nuclear Plant in Michigan replaced in November 1990. This replacement was accomplished through a 26-foot wide by 28-foot high opening cut into the wall of the containment building, about 45 feet above the original ground surface. Because this ground surface was at an approximately 3-H:1-V slope, leveling was required before replacement in order to provide access for the steam generators and adequate support for the heavy-duty gantry crane system used to transfer the generators. A 25-foot high reinforced soil wall was constructed to achieve the level surface. This paper describes the design and construction of the heavily loaded reinforced soil wall, including ground improvement measures required to obtain adequate wall stability. The performance of the wall under test loading will also be presented and discussed

  10. Seismic Behaviour of Composite Steel Fibre Reinforced Concrete Shear Walls

    Science.gov (United States)

    Boita, Ioana-Emanuela; Dan, Daniel; Stoian, Valeriu

    2017-10-01

    In this paper is presented an experimental study conducted at the “Politehnica” University of Timisoara, Romania. This study provides results from a comprehensive experimental investigation on the behaviour of composite steel fibre reinforced concrete shear walls (CSFRCW) with partially or totally encased profiles. Two experimental composite steel fibre reinforced concrete walls (CSFRCW) and, as a reference specimen, a typical reinforced concrete shear wall (RCW), (without structural reinforcement), were fabricated and tested under constant vertical load and quasi-static reversed cyclic lateral loads, in displacement control. The tests were performed until failure. The tested specimens were designed as 1:3 scale steel-concrete composite elements, representing a three storeys and one bay element from the base of a lateral resisting system made by shear walls. Configuration/arrangement of steel profiles in cross section were varied within the specimens. The main objective of this research consisted in identifying innovative solutions for composite steel-concrete shear walls with enhanced performance, as steel fibre reinforced concrete which was used in order to replace traditional reinforced concrete. A first conclusion was that replacing traditional reinforcement with steel fibre changes the failure mode of the elements, as from a flexural mode, in case of element RCW, to a shear failure mode for CSFRCW. The maximum lateral force had almost similar values but test results indicated an improvement in cracking response, and a decrease in ductility. The addition of steel fibres in the concrete mixture can lead to an increase of the initial cracking force, and can change the sudden opening of a crack in a more stable process.

  11. Mechanical performance and sustainability assessment of reinforced soil walls

    OpenAIRE

    Puig Damians, Ivan

    2016-01-01

    Soil reinforced retaining wall structures are materiallymore efficientthan competing construction solutions such as gravity and cantilever walls. Nevertheless, the behaviour and interactions between the com ponent materials are com plex and not fully understood. Current design methods are typically limited to simple cases with respect to material properties, geometry, and boundary conditions. Advanced numerical models using finite element and/or finite difference methods offer the possibility...

  12. Planning of installations in prefabricated buildings

    Directory of Open Access Journals (Sweden)

    Stanojević Ana D.

    2014-01-01

    Full Text Available Planning installations is becoming an increasing problem in construction, because the number of devices for technical supply is constantly increasing with continual progress in science and technology. Since the installations of the building can not be viewed unrelated of the construction, problem of its planning is more complicated in prefabricated buildings because the elements of construction are prefabricated. Planning was formerly performed by embedding the installation in prefabricated elements. This method had a lot of flaws, and modern approach tends setting installation out of prefabricated elements except when the traditional approach proves as economical. Although the hot water heating with radiators is the most practical way of heating in prefabricated buildings, the under floor heating systems have greater and greater use. Today, prefabricated sanitary cabins have a huge use and they are much more economical in comparison to special panels for bathrooms that were once create. Approaches in terms of planning electrical installation are different, but for conventional constructed buildings, as well as prefabricated buildings, the use of lightweight prefabricated walls with embedded installations, today is recommended, when the room is loaded with a large number of this installations and if it is possible.

  13. Capturing strain localization behind a geosynthetic-reinforced soil wall

    Science.gov (United States)

    Lai, Timothy Y.; Borja, Ronaldo I.; Duvernay, Blaise G.; Meehan, Richard L.

    2003-04-01

    This paper presents the results of finite element (FE) analyses of shear strain localization that occurred in cohesionless soils supported by a geosynthetic-reinforced retaining wall. The innovative aspects of the analyses include capturing of the localized deformation and the accompanying collapse mechanism using a recently developed embedded strong discontinuity model. The case study analysed, reported in previous publications, consists of a 3.5-m tall, full-scale reinforced wall model deforming in plane strain and loaded by surcharge at the surface to failure. Results of the analysis suggest strain localization developing from the toe of the wall and propagating upward to the ground surface, forming a curved failure surface. This is in agreement with a well-documented failure mechanism experienced by the physical wall model showing internal failure surfaces developing behind the wall as a result of the surface loading. Important features of the analyses include mesh sensitivity studies and a comparison of the localization properties predicted by different pre-localization constitutive models, including a family of three-invariant elastoplastic constitutive models appropriate for frictional/dilatant materials. Results of the analysis demonstrate the potential of the enhanced FE method for capturing a collapse mechanism characterized by the presence of a failure, or slip, surface through earthen materials.

  14. Nonlinear Analyses of Adobe Masonry Walls Reinforced with Fiberglass Mesh

    Directory of Open Access Journals (Sweden)

    Vincenzo Giamundo

    2014-02-01

    Full Text Available Adobe constructions were widespread in the ancient world, and earth was one of the most used construction materials in ancient times. Therefore, the preservation of adobe structures, especially against seismic events, is nowadays an important structural issue. Previous experimental tests have shown that the ratio between mortar and brick mechanical properties (i.e., strength, stiffness and elastic modulus influences the global response of the walls in terms of strength and ductility. Accurate analyses are presented in both the case of unreinforced and reinforced with fiberglass mesh when varying the mechanical properties of the materials composing the adobe masonry structure. The main issues and variability in the behavior of seismic resisting walls when varying the mechanical properties are herein highlighted. The aim of the overall research activity is to improve the knowledge about the structural behavior of adobe structural members unreinforced and reinforced with fiberglass mesh inside horizontal mortar joints.

  15. Inplane shear capacity of reinforced composite masonry block walls

    International Nuclear Information System (INIS)

    White, W.H.; Tseng, W.S.

    1981-01-01

    The objective of this paper is to describe a test program performed to determine the inplane shear capacity, stiffness and ductility of composite masonry walls subjected to earthquake type loadings. Specimens were simultaneously subjected to a range of compressive loads to simulate dead load; and inplane shear loads with full load reversal to simulate the earthquake cycling load. The influence of horizontal and vertical reinforcing steel percentages on the inplane shear capacity, stiffness and ductility was also investigated. (orig./HP)

  16. Gas leakage rate through reinforced concrete shear walls: Numerical study

    International Nuclear Information System (INIS)

    Wang Ting; Hutchinson, Tara C.

    2005-01-01

    Unlined reinforced concrete shear walls are often used as 'tertiary boundaries' in the United States Department of Energy (DOE) to house dangerous gases. An unanticipated event, such as an earthquake, may cause gases stored inside the walls to disperse into the environment resulting in excess pollution. To address this concern, in this paper, a methodology to numerically predict the gas leakage rate through these shear walls under lateral loading conditions is proposed. This methodology involves finite element and flow rate analysis. Strain distributions are obtained from the finite element analysis, and then used to simulate the crack characteristics on the concrete specimen. The flow rate through the damaged concrete specimen is then estimated using flow rate formulas available from the literature. Results from an experimental specimen are used to evaluate the methodology, and particularly its robustness in the flow rate estimation

  17. The Shrinkage Cracking Behavior in Reinforced Reactive Powder Concrete Walls

    Directory of Open Access Journals (Sweden)

    Samir A. Al-Mashhadi

    2017-07-01

    Full Text Available In this study, the reduced scale wall models were used (they are believed to resemble as much as possible the field conditions to study the shrinkage behavior of reactive powder concrete (RPC base restrained walls. Six base restrained RPC walls were casted in different length/height ratios of two ratios of steel fiber by volume in Summer. These walls were restrained by reinforced concrete bases to provide the continuous base restraint to the walls. The mechanical properties of reactive powder concrete investigated were; compressive strength between (75.3 – 140.1 MPa, splitting tensile strength between (5.7 – 13.9 MPa, flexural tensile strength (7.7 – 24.5 MPa, and static modulus of elasticity (32.7 – 47.1GPa. Based on the observations of this work, it was found that the cracks did not develop in the reduced scale of the reactive powder concrete (RPC walls restrained from movement at their bases for different L/H ratios (2, 5, and 10 and for two ratio of steel fiber (1% & 2% during 90 days period of drying conditions. Moreover, the shrinkage values increase toward the edges. Based on the results of this work, the increase in the maximum shrinkage values of walls with 1% steel fiber were (29%, 28%, 28% of the maximum shrinkage values of walls with 2% steel fiber of length/height ratios of (2, 5, and 10 respectively. The experimental observation in beam specimens showed that the free shrinkage, tensile strain capacity and elastic tensile strain capacity (at date of cracking of beams with 1% steel fiber were higher than the beams with 2% steel fiber by about (24%, (45% and (42% respectively

  18. Analysis and design of column reinforced masonry and concrete walls

    International Nuclear Information System (INIS)

    Doyle, J.M.; Roy, S.B.; Fang, S.J.

    1983-01-01

    Fundamental frequencies, maximum moments and maximum shear forces are determined as a function of the governing parameters, for several different boundary conditions. The quantities are obtained for uniform panels, for walls with openings typical of doorways and other penetrations, and for panels having a region of degraded stiffness. In addition to the internal forces and moment due to out-of-plane action, the stresses due to in-plane loading are also found. From the results curves are constructed which allow for easy computation of flexural frequency, and bending moments and shears due to dynamic loads normal to the wall. Furthermore, based on the studies of panels with geometric or material discontinuities, corrections to results for uniform panels are found which can be used if openings or weakened areas exist in the wall. Several conclusions are presented concerning effects on behavior due to varied column location, critical stiffness ratio for columns to be effective, and the effect of openings on overall behavior. A number of design recommendations are presented. While the motivation for the study came from the need to design masonry walls, the analysis results are applicable to solid concrete walls reinforced by vertical columns. (orig./HP)

  19. Soft impact testing of a wall-floor-wall reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Vepsä, Ari, E-mail: ari.vepsa@vtt.fi; Calonius, Kim; Saarenheimo, Arja; Aatola, Seppo; Halonen, Matti

    2017-01-15

    Highlights: • A wall-floor-wall reinforced concrete structure was built. • The structure was subjected to three almost identical soft impact tests. • Response was measured with accelerometers, displacement sensors and strain gauges. • Modal tests was also carried out with the same structure in different conditions. • The results are meant to be used for validation of computational methods and models. - Abstract: Assessing the safety of the reactor building of a nuclear power plant against the crash of an airplane calls for valid computational tools such as finite element models and material constitutive models. Validation of such tools and models in turn calls for reliable and relevant experimental data. The problem is that such data is scarcely available. One of the aspects of such a crash is vibrations that are generated by the impact. These vibrations tend to propagate from the impact point to the internal parts of the building. If strong enough, these vibrations may cause malfunction of the safety-critical equipment inside the building. To enable validation of computational models for this type of behaviour, we have conducted a series of three tests with a wall-floor-wall reinforced concrete structure under soft impact loading. The response of the structure was measured with accelerometers, displacement sensors and strain gauges. In addition to impact tests, the structure was subjected to modal tests under different conditions. The tests yielded a wealth of useful data for validation of computational models and better understanding about shock induced vibration physics especially in reinforced concrete structures.

  20. Numerical investigation of the leakage behaviour of reinforced concrete walls

    International Nuclear Information System (INIS)

    Christoph Niklasch; Laurent Coudert; Gregory Heinfling; Chantal Hervouet; Benoit Masson; Nico Herrmann; Lothar Stempniewski

    2005-01-01

    Full text of publication follows: For the verification of nuclear power plant safety, the leakage behaviour of the containment walls is of decisive importance. Extreme temperatures well over the water boiling temperature accompanied by high internal pressures can occur during an severe accident. In case of cracks through the entire thickness of the containment wall, an air-steam-water mixture may be released. In order to improve the knowledge of the leakage behaviour through cracks during such abnormal occurrences an experimental setup was developed at IfMB and several tests with different parameters were performed. The details of the experimental facility and the performed tests will be described in a separate paper. To improve the understanding of the behaviour of the tested wall elements during the tests numerical simulations of the performed leakage experiments are necessary. Reliable numerical tools provide a basis for the transfer of the leakage behaviour from the tested specimens to the behaviour of whole containment structures. To address the task of developing tools for the numerical simulation of the leakage behaviour of reinforced containment structures, EDF and IfMB decided to cooperate. During this cooperation two different numerical approaches had been made basing on existing tools and models of EDF and IfMB. In the following sections a short overview about the two different models will be given. For the numerical investigation of the leakage phenomena IfMB used the commercial Finite-Element- Program ADINA with ADINA's capability to solve coupled fluid-structure-interaction (FSI) problems. For the investigation of the moving of the specimen and the change of the crack profiles during the tests, it is important to take into account the heating of the specimen by the fluid flowing through the cracks. This is done by an iterative calculation of the fluid model and the structural model of the specimen. The thermo-dynamic boundary conditions representing

  1. Prefabricated house in real estate business development in Jabodetabek

    Science.gov (United States)

    Gumilang Raksamala Basmara Putra, Raka; Susanto, Dalhar

    2017-12-01

    Within constructional technology prefabricated house is known as a house whose most of the components like walls, roofs, toilets, and structural cubes and columns are designated and produced in factory and assembled in site. Based on the experience in certain countries, prefabricated house has successfully entered commercial market. Prefabricated house shows a better infestation value than conventional houses. With prefabrication technology, building construction could be done faster and cost lower price, along with a good craftsmanship quality. Until now, Indonesia is still facing settlements issues and one of them is housing backlog whose amount revolves around 13 Million units. Prefabricated houses potentially solve the settlement issue in Indonesia in a much faster way. Yet the development of prefabricated house has not been accepted well in the market yet, both by the producers and the consumers. This writing talks about the result of the research about the causes of the lack of development in Indonesia when it comes to prefabricated houses though the method of comparison; comparing prefabricated house with conventional house when it comes to its 1) productivity rate, 2) consumers preference and 3) infestation performance. The data is collected through survey methods, interview and questionnaires. The result shows that even though the productivity rate when it comes to quality and time is high, prefabricated house shows low productivity when it comes to cost because it requires greater cost than it is in conventional houses. Other than that, the lack of business development when it comes to prefabricated houses is caused by the low preference of consumers toward the product- because of its inflexibility and monotonous appearance. The infestation of prefabricated house development shows a low NPV and IRR. With a more proper infestation approach such as mass constructions with effective numbers, good flexibility, and various appearances, prefabricated house

  2. Fire resistance of a steel plate reinforced concrete bearing wall

    International Nuclear Information System (INIS)

    Kodaira, Akio; Kanchi, Masaki; Fujinaka, Hideo; Akita, Shodo; Ozaki, Masahiko

    2003-01-01

    Samples from a steel plate reinforced concrete bearing wall composed of concrete slab sandwiched between studded steel plates, were subjected to loaded fire resistance tests. There were two types of specimens: some were 1800 mm high while the rest were 3000 mm high ; thickness and width were the same for all specimens, at 200 mm and 800 mm, respectively. Under constant load conditions, one side of each specimen was heated along the standard fire-temperature curve. The results enabled us to approximate the relationship between the ratio of working load to concrete strength N/(Ac x c σ b) and the fire resistance time (t: minutes), as equation (1) for the 1800 mm - high specimen, and equation (2) for the 3000 mm - high specimen. N/(Ac x c σ b) = 2.21 x (1/t) 0.323 (1), .N/(Ac x c σ b) 2.30 x (1/t) 0.378 (2) In addition, the temperature of the unheated side of the specimens was 100degC at 240 minutes of continuous heating, clearly indicating that there was sufficient heat insulation. (author)

  3. Behavior of granular rubber waste tire reinforced soil for application in geosynthetic reinforced soil wall

    Directory of Open Access Journals (Sweden)

    G. G. D. RAMIREZ

    Full Text Available AbstractLarge quantities of waste tires are released to the environment in an undesirable way. The potential use of this waste material in geotechnical applications can contribute to reducing the tire disposal problem and to improve strength and deformation characteristics of soils. This paper presents a laboratory study on the effect of granular rubber waste tire on the physical properties of a clayey soil. Compaction tests using standard effort and consolidated-drained triaxial tests were run on soil and mixtures. The results conveyed an improvement in the cohesion and the angle of internal friction the clayey soil-granular rubber mixture, depending on the level of confining stress. These mixtures can be used like backfill material in soil retaining walls replacing the clayey soil due to its better strength and shear behavior and low unit weight. A numerical simulation was conducted for geosynthetic reinforced soil wall using the clayey soil and mixture like backfill material to analyzing the influence in this structure.

  4. Application Problems of Anchor Dowels in Reinforced Concrete Shear Wall and Frame Connections

    OpenAIRE

    Musa H. Arslan

    2016-01-01

    Strengthening of the existing seismically deficient reinforced concrete (RC) buildings is an important issue in earthquake prone regions. Addition of RC shear wall as infill or external walls into the structural system has been a commonly preferred strengthening technique since the Big Erzincan Earthquake occurred in Turkey, 1992. The newly added rigid infill walls act primarily as shear walls and relieve the non-ductile existing frames from being subjected to large shear demands providing th...

  5. The use of joint reinforcement in qualifying masonry walls in nuclear power plants

    International Nuclear Information System (INIS)

    Harris, H.G.; Becica, I.J.; Chokshi, N.C.; Con, V.N.; Hamid, A.A.

    1984-01-01

    Wire joint reinforcement has been traditionally used in block masonry walls for crack control and to provide continuity for multiple wythe walls. In a number of nuclear power plants, vertically unreinforced masonry walls that failed to meet the code allowable stresses for unreinforced masonry were qualified using joint reinforcement as a structural steel to carry lateral loads in the horizontal direction. It is the objective of this paper to examine the adequacy of this approach for seismic load application. A state-of-the-art review of available test data and code design provisions will be presented. It is concluded that the use of joint reinforcement to resist tensile stresses due to seismic loading is questionable because of the lack of test data available and especially the characterization of the cyclic behavior of joint reinforced masonry walls. Further research in this area is recommended

  6. Analytical Study on the Beyond Design Seismic Capacity of Reinforced Concrete Shear Walls

    Energy Technology Data Exchange (ETDEWEB)

    Nugroho, Tino Sawaldi Adi [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chi, Ho-Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    The OECD-NEA has organized an international benchmarking program to better understand this critical issue. The benchmark program provides test specimen geometry, test setup, material properties, loading conditions, recorded measures, and observations of the test specimens. The main objective of this research is to assess the beyond design seismic capacity of the reinforced concrete shear walls tested at the European Laboratory for Structural Assessment between 1997 and 1998 through participation in the OECD-NEA benchmark program. In this study, assessing the beyond design seismic capacity of reinforced concrete shear walls is performed analytically by comparing numerical results with experimental results. The seismic shear capacity of the reinforced concrete shear wall was predicted reasonably well using ABAQUS program. However, the proper calibration of the concrete material model was necessary for better prediction of the behavior of the reinforced concrete shear walls since the response was influenced significantly by the material constitutive model.

  7. Numerical Analysis of Carbon Fiber Reinforced Plastic (CFRP) Shear Walls and Steel Strips under Cyclic Loads Using Finite Element Method

    OpenAIRE

    Askarizadeh, N.; Mohammadizadeh, M. R.

    2017-01-01

    Reinforced concrete shear walls are the main elements of resistance against lateral loads in reinforced concrete structures. These walls should not only provide sufficient resistance but also provide sufficient ductility in order to avoid brittle fracture, particularly under strong seismic loads. However, many reinforced concrete shear walls need to be stabilized and reinforced due to various reasons such as changes in requirements of seismic regulations, weaknesses in design and execution, p...

  8. Evaluation of wall thinning of piping with reinforcing plates using ECT with controlled exciting field

    International Nuclear Information System (INIS)

    Ichihara, Toshiaki; Xie, Shejuan; Uchimoto, Tetsuya; Takagi, Toshiyuki

    2011-01-01

    No effective inspection method exists at present for detection and evaluation of wall thinning under the reinforcing plates to T-tubes in nuclear power plants, and the establishment of the inspection method is highly required. In this study, eddy current testing (ECT) with controlled exciting field is applied to evaluation of wall thinning under the reinforcing plates of T-tubes, and their feasibility is discussed. In order to induce eddy current field in deep region of doubled plates, pulse excitation and probe structures are investigated. Through experiments using specimens simulating tubes with reinforcing plates, it is shown that pulsed ECT and conventional TR type eddy current probe with optimized configuration have a capability of detecting and sizing the wall thinning under reinforcing plates. (author)

  9. Seismic Performance and Modeling of Reinforced Concrete and Post-Tensioned Precast Concrete Shear Walls

    OpenAIRE

    Tanyeri, Ahmet Can

    2014-01-01

    Past earthquakes have shown examples of unsatisfactory performance of buildings using reinforced concrete structural walls as the primary lateral-force-resisting system. In the 1994 Northridge earthquake, examples can be found where walls possessed too much overstrength, leading to unintended failure of collectors and floor systems, including precast and post-tensioned construction. In the 2010 Maule Chile earthquake, many structural wall buildings sustained severe damage. Although Chilean de...

  10. A new dedicated finite element for push-over analysis of reinforced concrete shear wall systems

    Directory of Open Access Journals (Sweden)

    Delal Doğru ORMANCI

    2016-06-01

    Full Text Available In this study, a finite element which has been analyzed based on anisotropic behavior of reinforced shear walls is developed. Element stiffness matrices were varied based on whether the element is in the tension or the compression zone of the cross-section. Nonlinear behavior of reinforced shear wall model is investigated under horizontal loads. This behavior is defined with a similar approach to plastic hinge assumption in frame structures that the finite element behaves lineer elastic between joints and plastic deformations are concentrated on joints as vertical plastic displacements. According to this acceptance, plastic behavior of reinforced shear wall occurs when the vertical strain reaches elastic strain limit. In the definition of finite element, displacement functions are chosen considering that the partition of shear walls just at floor levels, are enough for solution. Results of this study are compared with the solution obtained from a different computer programme and experimental results.

  11. Research Status on Reinforcement Connection Form of Precast Concrete Shear Wall Structure

    Science.gov (United States)

    Zhang, Zhuangnan; Zhang, Yan

    2018-03-01

    With the rapid development of Chinese economy and the speeding up the process of urbanization, housing industrialization has been paid more and more attention. And the fabricated structure has been widely used in China. The key of precast concrete shear wall structure is the connection of precast components. The reinforcement connection can directly affect the entirety performance and seismic behavior of the structure. Different reinforcement connections have a great impact on the overall behavior of the structure. By studying the characteristics of the reinforcement connection forms used in the vertical connection and horizontal connection of precast concrete shear wall, it can provide reference for the research and development of the reinforcement connection forms in the future.

  12. [Prefabrication of bone transplants].

    Science.gov (United States)

    Jagodzinski, M; Kokemüller, H; Jehn, P; Vogt, P; Gellrich, N-C; Krettek, C

    2015-03-01

    Prefabrication of bone transplants is a promising option for large defects of the long bones, especially if there is compromised vascularization of the defect. This is especially true for postinfection bone defects and other types of atrophic nonunion. The generation of a foreign body membrane (Masquelet's technique) has been investigated in order to ameliorate the response of the host tissue surrounding the defect. In an experimental animal study, a blood vessel within a bone construct could be used to generate customized, vascularized osteogenic constructs that can be used to treat large bone defects in the future.

  13. Damage Detection of Reinforced Concrete Shear Walls Using Mathematical Transformations

    Directory of Open Access Journals (Sweden)

    Hosein Naderpour

    2017-02-01

    Full Text Available Structural health monitoring is a procedure to provide accurate and immediate information on the condition and efficiency of structures. There is variety of damage factors and the unpredictability of future damage, is a necessity for the use of structural health monitoring. Structural health monitoring and damage detection in early stages is one of the most interesting topics that had been paid attention because the majority of damages can be repaired and reformed by initial evaluation ,thus the spread of damage to the structures, building collapse and rising of costs can be avoided .Detection of concrete shear wall damages are designed to withstand the lateral load on the structure is critical .Because failures and  malfunctions of shear walls can lead to serious damage or even progressive dilapidation of concrete structures .Change in stiffness and frequency can clearly show the damage occurrence. Mathematical transformation is also a tool to detect damage. In this article, with non- linear time history analysis, the finite element model of structures with concrete shear walls subject to four earthquakes have extracted and using Fourier and wavelet transform, the presence of shear walls is detected at the time of damage.

  14. Experimental determination of damping factors for walls of masonry and reinforced concrete

    International Nuclear Information System (INIS)

    Buttman, P.

    1983-01-01

    'Damping' is a fundamental parameter for the determination of the internal force with a given acceleration response spectrum when designing and dimensioning masonry and reinforced concrete walls for the loading case earthquake. The actual dampings of masonry and reinforced concrete walls are determined on a scale of 1:1 by means of a horizontal excitation at a chosen test setup. The test specimen have the dimensions b/h/d=100/200/11,5 cm and 24 cm. The horizontal and sinusoidal excitation of the test specimen is effected by a dynamic oscillating excitation with a maximum power of 20 kN. The evaluation of the measurements shows that the assumed damping values of 4% for the operating basis earthquake are realistic. In case of amplitudes corresponding to the loadings of the safe shutdown earthquake, however, dampings of 11% for reinforced concrete walls and of 24% for masonry walls were determined. This real damping behavior of reinforced concrete and masonry walls was documented by means of measurements, films and pictures. (orig.)

  15. Nondestructive evaluation of wall thinning occurred under reinforced plate by MFL method

    International Nuclear Information System (INIS)

    Kikuchi, Hiroaki; Sato, Kaito; Shimizu, Isamu

    2013-01-01

    Basic study on applying magnetic flux leakage (MFL) method using ac excitation to a nondestructive evaluation of wall thinning occurred under reinforcing plates in nuclear power plants were performed. Frequently, MFL method by means of dc field for exciting specimens is adopted, and only intensity of magnetic flux density is evaluated. On the other hand, MFL with alternating current enable us to utilize not only amplitude of magnetic flux density but also phase difference, which contributes to evaluation with higher accuracy. Here, specimens with slit and pipe with imitated wall thinning are prepared and magnetized using magnetic yoke with ac field, and then the leakage magnetic flux density and the phase difference on the specimen surface are investigated. Additionally, specimens imitated wall thinning occurred under reinforcing plates were investigated by MFL with ac excitation. (author)

  16. Reinforced Thermoplastic Polyimide with Dispersed Functionalized Single Wall Carbon Nanotubes

    Science.gov (United States)

    Lebron-Colon, Marisabel; Meador, Michael A.; Gaier, James R.; Sola, Francisco; Scheiman, Daniel A.; McCorkle, Linda S.

    2010-01-01

    Molecular pi-complexes were formed from pristine HiPCO single-wall carbon nanotubes (SWCNTs) and 1-pyrene- N-(4- N'-(5-norbornene-2,3-dicarboxyimido)phenyl butanamide, 1. Polyimide films were prepared with these complexes as well as uncomplexed SWCNTs and the effects of nanoadditive addition on mechanical, thermal, and electrical properties of these films were evaluated. Although these properties were enhanced by both nanoadditives, larger increases in tensile strength and thermal and electrical conductivities were obtained when the SWCNT/1 complexes were used. At a loading level of 5.5 wt %, the Tg of the polyimide increased from 169 to 197 C and the storage modulus increased 20-fold (from 142 to 3045 MPa). The addition of 3.5 wt % SWCNT/1 complexes increased the tensile strength of the polyimide from 61.4 to 129 MPa; higher loading levels led to embrittlement and lower tensile strengths. The electrical conductivities (DC surface) of the polyimides increased to 1 x 10(exp -4) Scm(exp -1) (SWCNT/1 complexes loading level of 9 wt %). Details of the preparation of these complexes and their effects on polyimide film properties are discussed.

  17. Seismic Retrofitting: Reinforced Concrete (RC shear wall versus Reinforcement of RC element by Carbon Fiber Reinforced Polymer (CFRP using PUSHOVER analysis

    Directory of Open Access Journals (Sweden)

    Yahya RIYAD

    2016-12-01

    Full Text Available Seismic retrofitting of constructions vulnerable to earthquakes is a current problem of great political and social relevance. During the last sixty years, moderate to severe earthquakes have occurred in Morocco (specifically in Agadir 1960 and Hoceima 2004. Such events have clearly shown the vulnerability of the building stock in particular and of the built environment in general. Hence, it is very much essential to retrofit the vulnerable building to cope up for the next damaging earthquake. In this paper, the focus will be on a comparative study between two techniques of seismic retrofitting, the first one is a reinforcement using carbon fiber reinforced polymer (CFRP applied to RC elements by bonding , and the second one is a reinforcement with a shear wall. For this study, we will use a non-linear static analysis -also known as Pushover analysis - on a reinforced concrete structure consisting of beams and columns, and composed from eight storey with a gross area of 240 m², designed conforming to the Moroccan Seismic code[1].

  18. Shake-table testing of a self-centering precast reinforced concrete frame with shear walls

    Science.gov (United States)

    Lu, Xilin; Yang, Boya; Zhao, Bin

    2018-04-01

    The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls (SPCW), which utilize a combination of unbonded prestressed post-tensioned (PT) tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.

  19. Post-cracking behavior of blocks, prisms, and small concrete walls reinforced with plant fiber

    Directory of Open Access Journals (Sweden)

    I. I. Soto

    Full Text Available Structural masonry using concrete blocks promotes the rationalization of construction projects, lowering the final cost of a building through the elimination of forms and the reduction of the consumption of reinforcement bars. Moreover, production of a block containing a combination of concrete and vegetable fiber sisal results in a unit with properties such as mechanical strength, stiffness, flexibility, ability to absorb energy, and post-cracking behavior that are comparable to those of a block produced with plain concrete. Herein are reported the results of a study on the post-cracking behavior of blocks, prisms, and small walls reinforced with sisal fibers (lengths of 20 mm and 40 mm added at volume fractions of 0.5% and 1%. Tests were performed to characterize the fibers and blocks and to determine the compressive strength of the units, prisms, and small walls. The deformation modulus of the elements was calculated and the stress-strain curves were plotted to gain a better understanding of the values obtained. The compression test results for the small walls reinforced with fibers were similar to those of the reference walls and better than the blocks and prisms with added fibers, which had resistances lower than those of the corresponding conventional materials. All elements prepared with the addition of sisal exhibited an increase in the deformation capacity (conferred by the fibers, which was observed in the stress-strain curves. The failure mode of the reference elements was characterized by an abrupt fracture, whereas the reinforced elements underwent ductile breakage. This result was because of the presence of the fibers, which remained attached to the faces of the cracks via adhesion to the cement matrix, thus preventing loss of continuity in the material. Therefore, the cement/plant fiber composites are advantageous in terms of their ductility and ability to resist further damage after cracking.

  20. Analysis of Dynamic Coupling Characteristics of the Slope Reinforced by Sheet Pile Wall

    Directory of Open Access Journals (Sweden)

    H. L. Qu

    2017-01-01

    Full Text Available Large deformation of slope caused by earthquake can lead to the loss of stability of slope and its retaining structures. At present, there have been some research achievements about the slope reinforcement of stabilizing piles. However, due to the complexity of the structural system, the coupling relationship between soil and pile is still not well understood. Hence it is of great necessity to study its dynamic characteristics further. In view of this, a numerical model was established by FLAC3D in this paper, and the deformation and stress nephogram of sheet pile wall in peak ground motion acceleration (PGA at 0.1 g, 0.2 g, and 0.4 g were obtained. Through the analysis, some conclusions were obtained. Firstly, based on the nephogram of motion characteristics and the positions of the slip surface and the retaining wall, the reinforced slope can be divided into 6 sections approximatively, namely, the sliding body parts of A, B, C, D, and E and the bedrock part F. Secondly, the deformation and stress distributions of slope reinforced by sheet pile wall were carefully studied. Based on the results of deformation calculation from time history analysis, the interaction force between structure and soil can be estimated by the difference of peak horizontal displacements, and the structure-soil coupling law under earthquake can be studied by this approach.

  1. Numerical Analysis of Carbon Fiber Reinforced Plastic (CFRP Shear Walls and Steel Strips under Cyclic Loads Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    N. Askarizadeh

    2017-12-01

    Full Text Available Reinforced concrete shear walls are the main elements of resistance against lateral loads in reinforced concrete structures. These walls should not only provide sufficient resistance but also provide sufficient ductility in order to avoid brittle fracture, particularly under strong seismic loads. However, many reinforced concrete shear walls need to be stabilized and reinforced due to various reasons such as changes in requirements of seismic regulations, weaknesses in design and execution, passage of time, damaging environmental factors, patch of rebar in plastic hinges and in some cases failures and weaknesses caused by previous earthquakes or explosion loads. Recently, Fiber Reinforced Polymer (FRP components have been extensively and successfully used in seismic improvement. This study reinforces FRP reinforced concrete shear walls and steel strips. CFRP and steel strips are evaluated by different yield and ultimate strength. Numerical and experimental studies are done on walls with scale 1/2. These walls are exposed to cyclic loading. Hysteresis curves of force, drift and strain of FRP strips are reviewed in order to compare results of numerical work and laboratory results. Both numerical and laboratory results show that CFRP and steel strips increase resistance, capacity and ductility of the structure.

  2. A comparative study on strengthening applications of prefabricated buildings in earthquake regions

    International Nuclear Information System (INIS)

    Arslan, M. Hakan; Gulay, F. Gulten

    2006-01-01

    Damages to prefabricated industrial structures caused by earthquakes in the last ten years in Turkey have occurred to an enormous extent. Among the causes of this damage, the inherent characteristic weakness of the load-carrying systems and constructing most of them according to the earthquake code applied before 1998 can be listed. The tragic situation that appeared after earthquakes emphasized that existing prefabricated constructions should be strengthened/improved according to the code which became valid after 1998. This study comprises three sections. The damage types in prefabricated reinforced concrete structures caused by earthquakes and the strengthening models (samples) that can be applied to these structures will be mentioned in the first and second sections, respectively. The last and the analytical part of the study will be about the selection of the most often damaged industrial construction type which is preferred in industrial regions and application of selecting strengthening methods performed by modeling these structures according to three different span types (1-S, 2-S, 3-S). The strengthening methods will be Sheer wall (SW), Steel Bracing (B), Steel Beam (SB) and Column Jacketing (CJ). All the systems will be calculated by using non-linear procedures (pushover analysis). The analysis performed by using a Software Package (DRAIN-2DX), will be applied to each frame in order to obtain load-displacement curves. The real hinge parameters will be defined using FEMA-356 to reflect the existing conditions. The results will be compared by considering the contribution of strengthening and especially system performance to displacement ductility. (author)

  3. Simulation of reinforced concrete short shear wall subjected to cyclic loading

    International Nuclear Information System (INIS)

    Parulekar, Y.M.; Reddy, G.R.; Vaze, K.K.; Pegon, P.; Wenzel, H.

    2014-01-01

    Highlights: • Prediction of the capacity of squat shear wall using tests and analysis. • Modification of model of concrete in the softening part. • Pushover analysis using softened truss theory and FE analysis is performed. • Modified concrete model gives reasonable accurate peak load and displacement. • The ductility, ultimate load and also crack pattern can be accurately predicted. - Abstract: This paper addresses the strength and deformation capacity of stiff squat shear wall subjected to monotonic and pseudo-static cyclic loading using experiments and analysis. Reinforced concrete squat shear walls offer great potential for lateral load resistance and the failure mode of these shear walls is brittle shear mode. Shear strength of these shear walls depend strongly on softening of concrete struts in principal compression direction due to principal tension in other direction. In this work simulation of the behavior of a squat shear wall is accurately predicted by finite element modeling by incorporating the appropriate softening model in the program. Modification of model of concrete in the softening part is suggested and reduction factor given by Vecchio et al. (1994) is used in the model. The accuracy of modeling is confirmed by comparing the simulated response with experimental one. The crack pattern generated from the 3D model is compared with that obtained from experiments. The load deflection for monotonic loads is also obtained using softened truss theory and compared with experimental one

  4. Effect of the selected seismic energy dissipation capacity on the materials quantity for reinforced concrete walls

    Directory of Open Access Journals (Sweden)

    José Miguel Benjumea Royero

    2017-02-01

    Full Text Available Context: Regarding their design of reinforced concrete structural walls, the Colombian seismic design building code allows the engineer to select one of the three seismic energy dissipation capacity (ordinary, moderate, and special depending on the seismic hazard of the site. Despite this, it is a common practice to choose the minor requirement for the site because it is thought that selecting a higher requirement will lead to larger structural materials amounts and, therefore, cost increments.  Method: In this work, an analytical study was performed in order to determine the effect of the selected energy dissipation capacity on the quantity of materials and ductility displacement capacity of R/C walls. The study was done for a region with low seismic hazard, mainly because this permitted to explore and compare the use of the three seismic energy dissipations capacities. The effect of different parameters such as the wall total height and thickness, the tributary loaded area, and the minimum volumetric steel ratio were studied. Results: The total amount of steel required for the walls with moderate and special energy dissipation capacity corresponds, on average, to 77% and 89%, respectively, of the quantity required for walls with minimum capacity. Conclusions: it is possible to achieve reductions in the total steel required weight when adopting either moderated or special seismic energy dissipation instead of the minimum capacity.  Additionally, a significant increment in the seismic ductility displacements capacity of the wall was obtained.

  5. PERFORMANCE OF RC AND FRC WALL PANELS REINFORCED WITH MILD STEEL AND GFRP COMPOSITES IN BLAST EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Garfield; William D. Richins; Thomas K. Larson; Chris P. Pantelides; James E. Blakeley

    2011-06-01

    The structural integrity of reinforced concrete structures in blast events is important for critical facilities. This paper presents experimental data generated for calibrating detailed finite element models that predict the performance of reinforced concrete wall panels with a wide range of construction details under blast loading. The test specimens were 1.2 m square wall panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consists of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bar reinforcement (Type A); FRC panels without additional reinforcement (Type B); FRC panels with steel bar reinforcement (Type C); NWC panels with glass fiber reinforced polymer (GFRP) bar reinforcement (Type D); and NWC panels reinforced with steel bar reinforcement and external bidirectional GFRP overlays on both faces (Type E). An additional three Type C panels were used as control specimens (CON). Each panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. The panels were instrumented with strain gauges, and accelerometers; in addition, pressure sensors and high speed videos were employed during the blast events. Panel types C and E had the best performance, whereas panel type B did not perform well. Preliminary dynamic simulations show crack patterns similar to the experimental results.

  6. Improved design of special boundary elements for T-shaped reinforced concrete walls

    Science.gov (United States)

    Ji, Xiaodong; Liu, Dan; Qian, Jiaru

    2017-01-01

    This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements of T-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

  7. A data fusion approach for progressive damage quantification in reinforced concrete masonry walls

    International Nuclear Information System (INIS)

    Vanniamparambil, Prashanth Abraham; Carmi, Rami; Kontsos, Antonios; Bolhassani, Mohammad; Khan, Fuad; Bartoli, Ivan; Moon, Franklin L; Hamid, Ahmad

    2014-01-01

    This paper presents a data fusion approach based on digital image correlation (DIC) and acoustic emission (AE) to detect, monitor and quantify progressive damage development in reinforced concrete masonry walls (CMW) with varying types of reinforcements. CMW were tested to evaluate their structural behavior under cyclic loading. The combination of DIC with AE provided a framework for the cross-correlation of full field strain maps on the surface of CMW with volume-inspecting acoustic activity. AE allowed in situ monitoring of damage progression which was correlated with the DIC through quantification of strain concentrations and by tracking crack evolution, visually verified. The presented results further demonstrate the relationships between the onset and development of cracking with changes in energy dissipation at each loading cycle, measured principal strains and computed AE energy, providing a promising paradigm for structural health monitoring applications on full-scale concrete masonry buildings. (paper)

  8. Structural performance of new thin-walled concrete sandwich panel system reinforced with bfrp shear connectors

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

    2013-01-01

    This paper presents a new thin-walled concrete sandwich panel system reinforced with basalt fiber-reinforced plastic (BFRP) with optimum structural performances and a high thermal resistance developed by Connovate and Technical University of Denmark. The shear connecting system made of a BFRP grid...... is described and provides information on the structural design with its advantages. Experimental and numerical investigations of the BFRP connecting systems were performed. The experimental program included testing of small scale specimens by applying shear (push-off) loading and semi-full scale specimens...... on finite element modelling showed that the developed panel system meets the objectives of the research and is expected to have promising future....

  9. Micro/Nanomechanical characterization of multi-walled carbon nanotubes reinforced epoxy composite.

    Science.gov (United States)

    Cui, Peng; Wang, Xinnan; Tangpong, X W

    2012-11-01

    In this paper, the mechanical properties of 1 wt.% multi-walled carbon nanotubes (MWCNTs) reinforced epoxy nanocomposites were characterized using a self-designed micro/nano three point bending tester that was on an atomic force microscope (AFM) to in situ observe MWCNTs movement on the sample surface under loading. The migration of an individual MWCNT at the surface of the nanocomposite was tracked to address the nanomechanical reinforcing mechanism of the nanocomposites. Through morphology analysis of the nanocomposite via scanning electron microscopy, AFM, and digital image correlation technique, it was found that the MWCNTs agglomerate and the bundles were the main factors for limiting the bending strength of the composites. The agglomeration/bundle effect was included in the Halpin-Tsai model to account for the elastic modulus of the nanocomposites.

  10. Hysteretic evaluation of seismic performance of normal and fiber reinforced concrete shear walls

    International Nuclear Information System (INIS)

    Choun, Young Sun; Hahm, Dae Gi

    2012-01-01

    The use of fibers in concrete or cement composites can enhance the performance of structural elements. Fibers have been used for a cement mixture to increase the toughness and tensile strength, and to improve the cracking and deformation characteristics. The addition of fibers into concrete can improve the ductility and increase the seismic resistance of concrete structures. The application of fibers to earthquake-resistant concrete structures has a major research topic. A recent study shows that an excellent seismic performance can be obtained in shear critical members constructed with high performance fiber reinforced cement composites. To increase the seismic performance of safety related concrete structures in nuclear power plants, fibers can be used. This study investigated the effect of fibers on the hysteretic behavior of a reinforced concrete (RC) shear wall by cyclic tests

  11. Hysteretic evaluation of seismic performance of normal and fiber reinforced concrete shear walls

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Young Sun; Hahm, Dae Gi [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    The use of fibers in concrete or cement composites can enhance the performance of structural elements. Fibers have been used for a cement mixture to increase the toughness and tensile strength, and to improve the cracking and deformation characteristics. The addition of fibers into concrete can improve the ductility and increase the seismic resistance of concrete structures. The application of fibers to earthquake-resistant concrete structures has a major research topic. A recent study shows that an excellent seismic performance can be obtained in shear critical members constructed with high performance fiber reinforced cement composites. To increase the seismic performance of safety related concrete structures in nuclear power plants, fibers can be used. This study investigated the effect of fibers on the hysteretic behavior of a reinforced concrete (RC) shear wall by cyclic tests.

  12. Study of the ruining behaviour of a structure with reinforced concrete carrying walls

    International Nuclear Information System (INIS)

    Manas, B.

    1998-06-01

    Nuclear facility buildings must be constructed with the respect of para-seismic rules. These rules are defined according to the most probable seismic risk estimated for the sites. This study concerns the ruining behaviour of a structure made of reinforced concrete walls. In a first part, a preliminary study on reinforced concrete is performed with the Castem 2000 finite elements code. This study emphasizes the non-linear phenomena that take place inside the material, such as the cracking of concrete and the plasticization of steels. In a second part, predictive calculations were performed on a U-shape structure. This structure was submitted to earthquakes of various magnitudes and the response of the structure was analyzed and interpreted. (J.S.)

  13. Effect of doping of multi-walled carbon nanotubes on phenolic based carbon fiber reinforced nanocomposites

    International Nuclear Information System (INIS)

    Saeed, Sadaf; Hakeem, Saira; Faheem, Muhammad; Alvi, Rashid Ahmed; Farooq, Khawar; Hussain, Syed Tajammul; Ahmad, Shahid Nisar

    2013-01-01

    We report on the effect of multi-walled carbon nanotubes (MWCNTs) on different properties of phenolic resin. A low content of MWCNTs (∼ 0.05 wt%) was mixed in phenolic resin and a stable dispersion was achieved by ultrasonication, followed by melt mixing. After curing the characterization of these composites was done by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infra-red spectroscopy (FTIR). The thermal and ablative properties of carbon fiber reinforced MWCNTs-phenolic nanocomposites were also studied. The addition of MWCNTs showed improvement in thermal stability and ablation properties.

  14. Study of the effect of hard projectiles impacting reinforced concrete walls

    International Nuclear Information System (INIS)

    Berriaud, C.; Sokolovsky, A.

    1977-01-01

    Among the risks examined in the framework of nuclear safety in France, quite unlikely events are examined as constituting a safety cover. This type of event includes the possible impact of aircrafts, or rotor splinters. Research on the limit strength of a wall under the impact of a hard projectile presently gives incentive results. First, a good agreement appears between works performed in parallel directions by EDF and CEA. Secondly, the special field of aerial projectiles is much better known as it was with previous formulations. Third, such research highly contributes to the knowledge of the mechanical strength of reinforced concrete structures [fr

  15. GEORGIAN PRODUCTION PREFABRICATED CERAMIC FIREPLACE

    International Nuclear Information System (INIS)

    Gaprindashvili, G.; Chemia, M.; Kartozia, L.

    2006-01-01

    General description and basic working principles of new construction prefabricated ceramic fireplace are given. The presented fireplace represents a unique synthesis of various fireplaces distributed in Georgian and some European countries; however, it is distinguished for its higher efficiency and other advantages. (author)

  16. Finite element modeling of tornado missile impact on reinforced concrete wall panels

    International Nuclear Information System (INIS)

    Zhang, Y.; Vallabhan, C.V.G.; McDonald, J.R.

    1993-01-01

    This paper describes a finite element model for the impact of large tornado-generated missiles with reinforced concrete wall panels. The analysis predicts the dynamic response of a wall panel when impacted by a missile with a large contact area such as an automobile. Quadratic finite elements are used to discretize the domain of the wall panel. Fundamental assumptions are based on the Mindlin and the related Reinsser plate theories. An 'embedded' model is employed to account for the reinforcing bars. The nonlinear behavior of concrete and steel bars are analyzed by means of time-dependent constitutive relationships. A model is proposed to describe the initial and subsequent yield surfaces of concrete material, which avoids underestimation of the effect of high hydrostatic stresses on the yielding behavior of concrete. Ottosen's four-parameter failure criterion is used to define the failure surface of concrete. A crack monitoring algorithm accounts for post-cracking and post-crushing behavior of concrete. Explicit time step integration of nonlinear dynamic equations are carried out using the finite element discretization of a concrete wall panel. As a practical application of the analysis technique, the contact failure pressure for a particular panel geometry can be calculated. The contact failure pressure and the elapsed time to failure after missile contact define a rectangular or triangular impulse loading to produce failure of the panel. Since automobile crashes are known to produce triangular impulse loads, the two pulses (failure and impact) can be compared to determine if a particular impact will fail the panels. Thus, a particular concrete panel can be analyzed to determine if it will fail under a postulated missile impact

  17. The electrostatic properties of Fiber-Reinforced-Plastics double wall underground storage gasoline tanks

    International Nuclear Information System (INIS)

    Li, Yipeng; Liu, Quanzhen; Meng, He; Sun, Lifu; Zhang, Yunpeng

    2013-01-01

    At present Fiber Reinforced Plastics (FRP) double wall underground storage gasoline tanks are wildly used. An FRP product with a resistance of more than 10 11 Ω is a static non-conductor, so it is difficult for the static electricity in the FRP product to decay into the earth. In this paper an experimental system was built to simulate an automobile gasoline filling station. Some electrostatic parameters of the gasoline, including volume charge density, were tested when gasoline was unloaded into a FRP double wall underground storage tank. Measurements were taken to make sure the volume charge density in the oil-outlet was similar to the volume charge density in the tank. In most cases the volume charge density of the gasoline was more than 22.7 μC m −3 , which is likely to cause electrostatic discharge in FRP double wall underground storage gasoline tanks. On the other hand, it would be hard to ignite the vapor by electrostatic discharge since the vapor pressure in the tanks is over the explosion limit. But when the tank is repaired or re-used, the operators must pay attention to the static electricity and some measurements should be taken to avoid electrostatic accident. Besides the relaxation time of charge in the FRP double wall gasoline storage tanks should be longer.

  18. New method for protecting mine roadways in thin coal seams by means of prefabricated yielding blocks

    Energy Technology Data Exchange (ETDEWEB)

    Peknik, J

    1983-05-01

    The use of concrete blocks for strata control in mine roadways driven in thin coal seams is evaluated. Two types of prefabricated blocks are used: BZT blocks made of reinforced concrete and yielding elements or popilbet blocks made of a mixture of fly ash (from coal power plants) and concrete. When the popilbet blocks were used no yielding elements were necessary. Mechanical properties of blocks made of reinforced concrete were controlled by yielding elements. Mechanical properties (compression strength) of the popilbet blocks were controlled by proportion of water, cement and fly ash. The BZT and the popilbet blocks were used for strata control in mine roadways in coal seams from 60 to 80 cm thick and dip angle from 5 to 18 degrees. Use of the BZT and the popilbet blocks reduced roadway deformation by about 50% in comparison to traditional strata control methods (timber cribbings, use of waste rock, etc.). Use of the blocks is explained. The BZT and the popilbet blocks were placed in a roadway wall. Height of the block wall equaled coal seam thickness. Yielding arched steel supports and timber liners were used for strata control in the roadway. The popilbet blocks were 50% less expensive than the BZT blocks. 9 references

  19. Preliminary Study on Evaluation of Impact Resistance Performance of Fiber Reinforced Concrete Walls

    International Nuclear Information System (INIS)

    Jin, Byeong Moo; Lee, Yun Seok; Kim, Young Jin; Jeon, Se Jin

    2012-01-01

    As the safety assessments of nuclear power plants for the hypothetical large civil aircraft crash should be made mandatory, studies on large aircraft-nuclear power plant impact analyses and assessments studies are actively in progress. For the safety assessment of nuclear power plants against large civil aircraft crash, it is practically impossible to conduct full-scale experiments. Therefore, analysis using general purpose numerical analysis program accompanied by scale model experiments and element experiments has been adopted for the safety assessment. The safety of nuclear power plants against large civil aircraft crash is able to be accomplished by enhancement of the impact resistance performance, such as increasing the wall thickness, increasing the strength of concrete and using the fiber reinforced concrete which is able to be acquired by relatively simple process of adding fibers to a concrete mix without significant change of design and construction. A research for the enhancement of impact resistance performance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application rate, is in progress. In this study, before the safety assessment of nuclear power plants against large civil aircraft crash, we assess the impact resistance performance of concrete wall depending upon type of fibers and impact velocity of objects

  20. Preliminary Study on Evaluation of Impact Resistance Performance of Fiber Reinforced Concrete Walls

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Byeong Moo; Lee, Yun Seok; Kim, Young Jin [Daewoo E and C Co. Ltd., Suwon (Korea, Republic of); Jeon, Se Jin [Ajou University, Suwon (Korea, Republic of)

    2012-05-15

    As the safety assessments of nuclear power plants for the hypothetical large civil aircraft crash should be made mandatory, studies on large aircraft-nuclear power plant impact analyses and assessments studies are actively in progress. For the safety assessment of nuclear power plants against large civil aircraft crash, it is practically impossible to conduct full-scale experiments. Therefore, analysis using general purpose numerical analysis program accompanied by scale model experiments and element experiments has been adopted for the safety assessment. The safety of nuclear power plants against large civil aircraft crash is able to be accomplished by enhancement of the impact resistance performance, such as increasing the wall thickness, increasing the strength of concrete and using the fiber reinforced concrete which is able to be acquired by relatively simple process of adding fibers to a concrete mix without significant change of design and construction. A research for the enhancement of impact resistance performance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application rate, is in progress. In this study, before the safety assessment of nuclear power plants against large civil aircraft crash, we assess the impact resistance performance of concrete wall depending upon type of fibers and impact velocity of objects

  1. Investigation of Mechanical Properties and Morphology of Multi-Walled Carbon Nanotubes Reinforced Cellulose Acetate Fibers

    Directory of Open Access Journals (Sweden)

    Quazi Nahida Sultana

    2017-11-01

    Full Text Available Cellulose acetate (CA fibers were reinforced with multi-walled carbon nanotubes (MWCNTs at 0.5%, 1.0%, 1.5% and 2.0%. Yield strength, ultimate tensile strength, fracture strain and toughness of the nanocomposite fiber increased up to 1.5 wt. % of the carbon nanotube (CNT loading, however, further inclusion (2.0% of MWCNTs in CA decreased the mechanical properties. Experimental properties were also compared with analytical predictions using a Shear lag model for strength and the rule of mixture for modulus. A solution spinning process, coupled with sonication, mixing, and extrusion, was used to process the CNT-reinforced composite fiber. Scanning electron microscopy (SEM images of the cross sections of neat CA and CA-MWCNT fibers showed the formation of voids and irregular features. The enhanced interconnected fibrillation in the CNT-reinforced CA samples resulted in improved mechanical properties, which were observed by tensile testing. Fourier transform infrared spectroscopy (FTIR spectra showed the area under the curve for C–H bonding after the inclusion of CNT. There was no significant shift of wavenumber for the inclusion of MWCNT in the CA matrix, which indicates that the sonication process of the CNT-loaded solution did not degrade the CA bonding structure.

  2. Floors number influence on the instability parameter of reinforced concrete wall- or core-braced buildings

    Directory of Open Access Journals (Sweden)

    R. J. Ellwanger

    Full Text Available This work aims to investigate the floors number influence on the instability parameter limit α1 of buildings braced by reinforced concrete walls and/or cores. Initially, it is showed how the Beck and König discrete and continuous models are utilized in order to define when a second order analysis is needed. The treatment given to this subject by the Brazilian code for concrete structures design (NBR 6118 is also presented. It follows a detailed analytical study that led to the derivation of equations for the limit α1 as functions of the floors number; a series of examples is presented to check their accuracy. Results are analyzed, showing the precision degree achieved and topics for continuity of research in this field are indicated.

  3. Dynamic Behavior of Nanocomposites Reinforced with Multi-Walled Carbon Nanotubes (MWCNTs

    Directory of Open Access Journals (Sweden)

    Chun-Yu Lai

    2013-06-01

    Full Text Available The influence of multi-walled carbon nanotubes (MWCNT on the structural dynamic behavior of MWCNT/epoxy nanocomposites was investigated. Two different types of MWCNTs, pristine MWCNT and functionalized MWCNT, were used in this study. Carboxylic acid-functionalized MWCNTs (MWCNT-COOH were obtained by oxidation pristine MWCNTs via sonication in sulfuric-nitric acid and characterized by Fourier transform infrared spectroscopy (FTIR. Dynamic behaviors of the MWCNT reinforced nanocomposite including the natural frequency and damping ratio were determined using free vibration test. Experimental results showed that the damping ratio of the nanocomposite decreases with the increase of the MWCNT addition, while the natural frequency is increasing with the increase of the MWCNT addition. Functionalized MWCNTs improved the interfacial bonding between the nanotubes and epoxy resin resulting in the reduction of the interfacial energy dissipation ability and enhancement of the stiffness.

  4. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    Energy Technology Data Exchange (ETDEWEB)

    Ile, Nicolas; Frau, Alberto, E-mail: alberto.frau@cea.fr

    2017-04-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  5. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    International Nuclear Information System (INIS)

    Ile, Nicolas; Frau, Alberto

    2017-01-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  6. Cracked reinforced concrete walls of chimneys, silos and cooling towers as result of using formworks

    Directory of Open Access Journals (Sweden)

    Maj Marek

    2018-01-01

    Full Text Available There are presented in this paper some problems connected with reinforced concrete shell objects operation in the aggressive environment and built in method of formworks. Reinforced concrete chimneys, cooling towers, silos and other shells were built for decades. Durability of cracked shells are one of the most important parameters during process of designing, construction and exploitation of shells. Some reasons of appearance of horizontal and vertical cracks as temperature, pressure of stored material, live loads e.g. dynamic character of wind, moisture, influence of construction joints, thermal insulation, chemistry active environmental etc. reduce the carrying capacity of the walls. Formworks, as is occurred recently, are the reason for technological joints with leaking connection, imperfections of flexible formworks slabs and as result can initiate cracks. Cracked surface of this constructions causes decreasing capacity and lower the state of reliability. Horizontal, vertical cracks can caused corrosion of concrete and steel bars, decreasing stiffness of contraction, increasing of deflection and carbonation of concrete cover. Local and global imperfactions of concrete shells are increasing according to greater number of cracks...

  7. State of the art and further development of reinforced concrete wall cells for nuclear power plant construction

    International Nuclear Information System (INIS)

    Uhlemann, E.; Wartenberg, J.

    1985-01-01

    Reinforced concrete wall cells have been developed for nuclear power plant construction by the USSR and GDR. In this article, a new type of these cells, which will be used for constructing auxiliary equipment of the Stendal nuclear power plant, is described

  8. An overview of an experimental program for testing large reinforced concrete shear walls

    International Nuclear Information System (INIS)

    Farrar, C.R.; Bennett, J.G.

    1989-01-01

    The Seismic Category I Structures Program is being carried out at the Los Alamos National Laboratory under sponsorship of the US Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research. In the class of structure being investigated, the primary lateral load-resisting structural element is the reinforced concrete shear wall. Previous results from microconcrete models indicated that these structures responded to seismic excitations with initial frequencies that were reduced by factors of 2 or more over those calculated based on an uncracked cross-section strength-of-materials approach. Furthermore, though the structures themselves were shown to have sufficient reserve margins, the equipment and piping are designed to response spectra that are based on uncracked cross-sectional member properties, and these spectra may not be inappropriate for actual building responses. The current phase of the program is aimed at verification of these conclusions using conventional concrete structures to demonstrate that previous microconcrete results can be scaled to prototype structures. A new configuration of a shear wall structure was designed and tested to investigate the analytical-experimental differences observed during the previous model testing. Shear wall height-to-length aspect ratios were to vary from 1 to 0.25. Percentage steel ratios were to vary from 0.25% to 0.6% by area, in both horizontal and vertical directions. The test structures are shown in Fig. 1. TRG-1 and -2 were constructed with microconcrete. TRG-3, -4, -5, and -6 were constructed with conventional (19-mm aggregate) concrete. 11 refs., 4 figs

  9. Preparation, characterization and properties of acid functionalized multi-walled carbon nanotube reinforced thermoplastic polyurethane nanocomposites

    International Nuclear Information System (INIS)

    Kumar Barick, Aruna; Kumar Tripathy, Deba

    2011-01-01

    Graphical abstract: Highlights: → Preparation and characterization of TPU nanocomposite for tailor made applications. → The structural analyses were carried out by FTIR, WAXD, FESEM and HRTEM. → The thermal and dynamic mechanical properties were evaluated by TGA, DSC and DMA. → The dynamic rheological behavior was investigated by RPA in frequency sweep. → The frequency dependence of electrical properties was studied by LCR meter. - Abstract: The multi-walled carbon nanotube (MWNT) reinforced thermoplastic polyurethane (TPU) nanocomposites were prepared through melt compounding method followed by compression molding. The spectroscopic study indicated that a strong interfacial interaction was developed between carbon nanotube (CNT) and the TPU matrix in the nanocomposites. The microscopic observation showed that the CNTs were homogeneously dispersed throughout the TPU matrix well apart from a few clusters. The results from thermal analysis indicated that the glass transition temperature (T g ) and storage modulus (E') of the nanocomposites were increased with increase in CNTs content and their thermal stability were also improved in comparison with pure TPU matrix. The rheological analysis showed the low frequency plateau of shear modulus and the shear thinning behavior of the nanocomposites. The electrical behaviors of the nanocomposites are increased with increase in weight percent (wt%) of CNT loading. The mechanical properties of nanocomposites were substantially improved by the incorporation of CNTs into the TPU matrix.

  10. Feeding Single-Walled Carbon Nanotubes or Graphene to Silkworms for Reinforced Silk Fibers.

    Science.gov (United States)

    Wang, Qi; Wang, Chunya; Zhang, Mingchao; Jian, Muqiang; Zhang, Yingying

    2016-10-12

    Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms. Spectroscopy study indicated that nanocarbon additions hindered the conformation transition of silk fibroin from random coil and α-helix to β-sheet, which may contribute to increased elongation at break and toughness modules. We further investigated the pyrolysis of modified silk, and a highly developed graphitic structure with obviously enhanced electrical conductivity was obtained through the introduction of SWNTs and graphene. The successful generation of these SWNT- or graphene-embedded silks by in vivo feeding is expected to open up possibilities for the large-scale production of high-strength silk fibers.

  11. Aligned multi-walled carbon nanotube-reinforced composites: processing and mechanical characterization

    International Nuclear Information System (INIS)

    Thostenson, Erik T.; Chou, Tsuwei

    2002-01-01

    Carbon nanotubes have been the subject of considerable attention because of their exceptional physical and mechanical properties. These properties observed at the nanoscale have motivated researchers to utilize carbon nanotubes as reinforcement in composite materials. In this research, a micro-scale twin-screw extruder was used to achieve dispersion of multi-walled carbon nanotubes in a polystyrene matrix. Highly aligned nanocomposite films were produced by extruding the polymer melt through a rectangular die and drawing the film prior to cooling. Randomly oriented nanocomposites were produced by achieving dispersion first with the twin-screw extruder followed by pressing a film using a hydraulic press. The tensile behaviour of the aligned and random nanocomposite films with 5 wt.{%} loading of nanotubes were characterized. Addition of nanotubes increased the tensile modulus, yield strength and ultimate strengths of the polymer films, and the improvement in elastic modulus with the aligned nanotube composite is five times greater than the improvement for the randomly oriented composite. (author)

  12. Seismic Failure Mechanism of Reinforced Cold-Formed Steel Shear Wall System Based on Structural Vulnerability Analysis

    Directory of Open Access Journals (Sweden)

    Jihong Ye

    2017-02-01

    Full Text Available A series of structural vulnerability analyses are conducted on a reinforced cold-formed steel (RCFS shear wall system and a traditional cold-formed steel (CFS shear wall system subjected to earthquake hazard based on forms in order to investigate their failure mechanisms. The RCFS shear wall adopts rigid beam-column joints and continuous concrete-filled CFS tube end studs rather than coupled-C section end studs that are used in traditional CFS shear walls, to achieve the rigid connections in both beam-column joints and column bases. The results show that: the RCFS and traditional CFS shear wall systems both exhibit the maximum vulnerability index associated with the failure mode in the first story. Therefore, the first story is likely to be a weakness of the CFS shear wall system. Once the wall is damaged, the traditional CFS shear wall system would collapse because the shear wall is the only lateral-resisting component. However, the collapse resistance of the RCFS shear wall system is effectively enhanced by the second defense, which is provided by a framework integrated by rigid beam-column joints and fixed column bases. The predicted collapse mode with maximum vulnerability index that was obtained by structural vulnerability analysis agrees well with the experimental result, and the structural vulnerability method is thereby verified to be reasonable to identify the weaknesses of framed structures and predict their collapse modes. Additionally, the quantitative vulnerability index indicates that the RCFS shear wall system exhibits better robustness compared to the traditional one. Furthermore, the “strong frame weak wallboard” and the “strong column weak beam” are proposed in this study as conceptional designations for the RCFS shear wall systems.

  13. Non-linear analysis of the behaviour of a thin and squat reinforced concrete wall on a seismic table

    International Nuclear Information System (INIS)

    Mazars, J.; Ghavamian, S.; Ile, N.; Reynouard, J.M.

    1998-01-01

    This work concerns the modeling and analysis of the seismic behaviour of a thin reinforced concrete wall using an experiment performed by the NUPEC (Nuclear Power Engineering Corporation) Japanese organisation with the Tadotsu seismic table. The wall with a height/width ratio close to 1, has its extremities stiffened and its base embedded. The wall, loaded on its top with a 122 t weight, is submitted to several seismic levels up to its collapse. A non-linear seismic analysis and different 2-D and 3-D finite elements modeling were used to simulate the behaviour of the structure submitted to a strong dynamic shear. The results presented in this paper belong to the ''Seismic Shear Wall Standard Problem'' benchmark jointly organized the NUPEC and OECD organizations. (J.S.)

  14. Economic aspect comparison between steel plate reinforced concrete and reinforced concrete technique in reactor containment wall construction

    International Nuclear Information System (INIS)

    Yuliastuti; Sriyana

    2008-01-01

    Construction costs of nuclear power plant were high due to the construction delays, regulatory delays, redesign requirement, and difficulties in construction management. Based on US DOE (United States Department of Energy) study in 2004, there were thirteen advanced construction technologies which were potential to reduce the construction time of nuclear power plant. Among these technologies was the application of steel-plate reinforced concrete (SC) on reactor containment construction. The conventional reinforced concrete (RC) technique were built in place and require more time to remove framework since the external form is temporary. Meanwhile, the SC technique offered a more efficient way to placing concrete by using a permanent external form made of steel. The objective of this study was to calculate construction duration and economic comparison between RC and SC technique. The result of this study showed that SC technique could reduce the construction time by 60% and 29,7% cost reduced compare to the RC technique. (author)

  15. SEISMIC PERFORMANCE OF A PRECAST REINFORCED CONCRETE WALL WITH CUT-OUT OPENING RETROFITTED USING CARBON FIBRE STRIPS

    Directory of Open Access Journals (Sweden)

    Fofiu M.

    2015-05-01

    Full Text Available The Precast Reinforced Concrete Wall Panel (PRCWP presented in this paper is part of an experimental study regarding the seismic performance of precast reinforced concrete wall panels, strengthening strategies and investigation on the weakening induced by modifying the opening in these elements due to architectural demands, change of function of buildings or other reasons. The element presented is 1:1.2 scale typical Reinforced Concrete Wall Panel with a window opening used in Romania, in which the opening was changed to a door opening due to comfort considerations. The specimen was subjected to cyclic loading with the lateral loads being applied in displacement control of 0.1% drift ratio. This simulates the shear behaviour of the element. After testing the unstrengthen element we proceed to retrofit it using Carbon Fibre Strips anchored with Carbon Fibre Mash. The purpose of the paper is to present the strengthening strategy and restore the initial load bearing capacity of the element or even increase it. The experimental results of strengthen and unstrengthen specimens will be presented.

  16. Timber Chips as the Insulation Material for Energy Saving in Prefabricated Offices

    Directory of Open Access Journals (Sweden)

    Yupeng Wang

    2016-06-01

    Full Text Available This research demonstrates the feasibility of a roof insulation method for prefabricated offices that uses vinyl packed timber chips to reduce air conditioning loads (hereinafter referred to as AC loads and which also improves indoor thermal comfort. The advantages of the new roof insulation method were revealed through comparing the impacts of four roof types on prefabricated offices. The AC load and indoor thermal comfort (surface temperature and air temperature were evaluated. The disposal of scrap timber discarded from building construction projects is costing money, and is also a waste of natural resources. The assessment of a new roof insulation method with timber chips demonstrates the advanced usage of timber chips, reducing the environmental load in the building construction process. On the other hand, since prefabricated offices have lower thermal storage capacities and are less airtight than RC (reinforced concrete or S (steel structured buildings, the AC load consumption and indoor thermal comfort exacerbation in prefabricated offices is more serious. Especially in summer, a large amount of solar energy absorption from the roof raises the indoor air temperature and significantly increases the cooling load. This research contributes to the environmental design for prefabricated offices, and develops a method for the reuse of wood chips.

  17. Experimental and numerical investigations of higher mode effects on seismic inelastic response of reinforced concrete shear walls

    Science.gov (United States)

    Ghorbanirenani, Iman

    This thesis presents two experimental programs together with companion numerical studies that were carried out on reinforced concrete shear walls: static tests and dynamic (shake table) tests. The first series of experiments were monotonic and cyclic quasi-static testing on ductile reinforced concrete shear wall specimens designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The tests were carried out on full-scale and 1:2.37 reduced scale wall specimens to evaluate the seismic design provisions and similitude law and determine the appropriate scaling factor that could be applied for further studies such as dynamic tests. The second series of experiments were shake table tests conducted on two identical 1:2.33 scaled, 8-storey moderately ductile reinforced concrete shear wall specimens to investigate the effects of higher modes on the inelastic response of slender walls under high frequency ground motions expected in Eastern North America. The walls were designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The objectives were to validate and understand the inelastic response and interaction of shear, flexure and axial loads in plastic hinge zones of the walls considering the higher mode effects and to investigate the formation of second hinge in upper part of the wall due to higher mode responses. Second mode response significantly affected the response of the walls. This caused inelastic flexural response to develop at the 6th level with approximately the same rotation ductility compared to that observed at the base. Dynamic amplification of the base shear forces was also observed in both walls. Numerical modeling of these two shake table tests was performed to evaluate the test results and validate current modeling approaches. Nonlinear time history analyses were carried out by the reinforced concrete fibre element (OpenSees program) and finite element (VecTor2 program

  18. Alternativa estructural de refuerzo horizontal en muros de mampostería Structural alternative of horizontal reinforcement in masonry walls

    Directory of Open Access Journals (Sweden)

    Diego Fernando Páez Moreno

    2009-01-01

    Full Text Available La implementación de refuerzo horizontal en muros de mampostería con ladrillo macizo de arcilla cocida es una técnica empleada en varios países. En este trabajo se propone un análisis para muros de mampostería representativos de la ciudad de Tunja con la implementación de grafiles de acero como alternativa de refuerzo horizontal. Este estudio involucra la definición de los tipos de materiales a emplear, las características de los muros a ensayar y las variables que se deben aplicar, tanto en los muros como en la ejecución del ensayo de compresión diagonal, que define tipos de muros con características propias de refuerzo. Los resultados del proceso de análisis del comportamiento individual y general de los muros de mampostería sometidos al ensayo de compresión diagonal permiten identificar la variación del esfuerzo cortante representativo para cada tipo de muro, en relación con el refuerzo empleado en los diferentes modelos y la tipología de falla.Implementation of horizontal reinforcement in masonry walls with solid cooked clay bricks is a commonly used technique in several countries. This article is intended to analyze masonry walls representatives of Tunja City, with implementation of small steel bars as an alternative of horizontal reinforcement. This study involves definition of types of materials to be used, characteristics of walls to be tested, and variables which should be applied in both walls and during the execution of the diagonal compression test which defines the types of walls with own characteristics of reinforcement. Results from individual and general behavior analysis process of masonry walls subject to diagonal compression tests allow identifying variation of shear stress for each kind of wall, in relation to reinforcement used in several models and failure typology.

  19. Prefabricated vertical drains, vol. I : engineering guidelines.

    Science.gov (United States)

    1986-09-01

    This volume presents procedures and guidelines applicable to the design and instal : tion of prefabricated vertical drains to accelerate consolidation of soils. The : contents represent the Consultant's interpretation of the state-of-the-art as of : ...

  20. Hydroxyapatite reinforced with multi-walled carbon nanotubes and bovine serum albumin for bone substitute applications

    Science.gov (United States)

    Gholami, Fatemeh; Noor, Ahmad-Fauzi Mohd

    2016-12-01

    The similarity of the chemical composition of HA to the mineral phase of bone and its excellent biocompatibility meets the requirement of materials designed for bone substitute purpose. The application of HA in load bearing devices is limited by its poor mechanical properties. CNTs with outstanding stiffness, strength, combined with their small size and large interfacial area, suggest that they may have great potential as a reinforcing agent for HA. This work aims to develop the Hydroxyapatite/Multi-walled Carbon Nanotubes/Bovine Serum Albumin (HA/MWCNTs/BSA) composites with different types of MWCNTs including hydroxylated and carboxylated MWCNTs (MWCNTs-OH, MWCNTs-COOH), and evaluation of mechanical strength and in vitro cellular response of developed composites. HA powder was mixed with de-ionized water, 15 wt.% BSA, and 0.5 wt.% of different MWCNTs* (> 95%), MWCNTs (> 99.9%), MWCNTs-OH (> 99.9%), MWCNTs-COOH (> 99.9%) to produce composites. Among all developed composites, the HA/MWCNTs-COOH/BSA shows the highest compressive strength (29.57 MPa). The cytotoxic effect of HA/MWCNTs-COOH/BSA with different concentrations (6.25 to 200 µg/ml) was evaluated by MTT assay against normal human colon fibroblast (CCD-18Co cell line). At low concentration, all developed composites were found to be non-cytotoxic when treated to the human fibroblast cells and did not elicit cytotoxic effects on cell proliferation and the highest values of cell viability (283%) for the HA/MWCNTs-COOH/BSA composites obtained; whereas when the concentration was increased, the reduction in cell viability was observed. The novel composites showed favorable cytocompatibility with improved compressive strength which make it applicable to use in range of trabecular bone.

  1. The Prefabricated Interior Design Studio: An Exploration into the History and Sustainability of Interior Prefabrication

    Science.gov (United States)

    Schneiderman, Deborah; Freihoefer, Kara

    2013-01-01

    This article examines the integration of prefabrication into an interior design studio. A review of the literature revealed that while there is a paucity of categorical research focused on this subject, the subject is historically significant with an abundance of evidence regarding the prefabrication of the interior environment dating back…

  2. Development and application of new composite grouting material for sealing groundwater inflow and reinforcing wall rock in deep mine.

    Science.gov (United States)

    Jinpeng, Zhang; Limin, Liu; Futao, Zhang; Junzhi, Cao

    2018-04-04

    With cement, bentonite, water glass, J85 accelerator, retarder and water as raw materials, a new composite grouting material used to seal groundwater inflow and reinforce wall rock in deep fractured rock mass was developed in this paper. Based on the reaction mechanism of raw material, the pumpable time, stone rate, initial setting time, plastic strength and unconfined compressive strength of multi-group proportion grouts were tested by orthogonal experiment. Then, the optimum proportion of composite grouting material was selected and applied to the grouting engineering for sealing groundwater inflow and reinforcing wall rock in mine shaft lining. The results show the mixing proportion of the maximum pumpable time, maximum stone rate and minimum initial setting time of grout are A K4 B K1 C K4 D K2 , A K3 B K1 C K1 D K4 and A K3 B K3 C K4 D K1 , respectively. The mixing proportion of the maximum plastic strength and unconfined compressive strength of grouts concretion bodies are A K1 B K1 C K1 D K3 and A K1 B K1 C K1 D K1 , respectively. Balanced the above 5 indicators overall and determined the optimum proportion of grouts: bentonite-cement ratio of 1.0, water-solid ratio of 3.5, accelerator content of 2.9% and retarder content of 1.45%. This new composite grouting material had good effect on the grouting engineering for sealing groundwater inflow and reinforcing wall rock in deep fractured rock mass.

  3. An effective simplified model of composite compression struts for partially-restrained steel frame with reinforced concrete infill walls

    Science.gov (United States)

    Sun, Guohua; Chuang-Sheng, Walter Yang; Gu, Qiang; DesRoches, Reginald

    2018-04-01

    To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained (PR) steel frames with solid reinforced concrete (RC) infill walls, an innovative simplified model of composite compression struts is proposed on the basis of experimental observation on the cracking distribution, load transferring mechanism, and failure modes of RC infill walls filled in PR steel frame. The proposed composite compression struts model for the solid RC infill walls is composed of α inclined struts and main diagonal struts. The α inclined struts are used to reflect the part of the lateral force resisted by shear connectors along the frame-wall interface, while the main diagonal struts are introduced to take into account the rest of the lateral force transferred along the diagonal direction due to the complicated interaction between the steel frame and RC infill walls. This study derives appropriate formulas for the effective widths of the α inclined strut and main diagonal strut, respectively. An example of PR steel frame with RC infill walls simulating simulated by the composite inclined compression struts model is illustrated. The maximum lateral strength and the hysteresis curve shape obtained from the proposed composite strut model are in good agreement with those from the test results, and the backbone curve of a PR steel frame with RC infill walls can be predicted precisely when the inter-story drift is within 1%. This simplified model can also predict the structural stiffness and the equivalent viscous damping ratio well when the inter-story drift ratio exceeds 0.5%.

  4. Non-Destructive Detection of Rebar Buried in a Reinforced Concrete Wall with Wireless Passive SAW Sensor

    Science.gov (United States)

    Fan, Yanping; Ji, Xiaojun; Cai, Ping; Lu, Qianhui

    2013-01-01

    In order to reduce the damage to the old reinforced concrete walls and work out the best construction scheme during the renovation of old buildings, it is often required to detect the position of rebar buried in concrete walls. In this paper, we propose a non-destructive method to detect the buried rebar by self-inductive sensor combined with surface acoustic wave resonator (SAWR). The proposed method has the advantages of wireless, passive and convenient operations. In our new design, the sensing element of self-inductance coil was made as a component of SAWR matching network. The distribution of rebar could be measured according to the system resonant frequency, using a signal demodulation device set. The depth of buried rebar and the deviation of output resonant frequency from inherent frequency of SAWR have an inverse relation. Finally, the validity of the method was verified in theoretical calculation and simulation.

  5. Fire resistance of prefabricated monolithic slab

    Directory of Open Access Journals (Sweden)

    Gravit Marina

    2017-01-01

    Full Text Available A prefabricated monolithic slab (PMS has a number of valuable advantages, they allow to significantly decrease the weight of construction keeping the necessary structural-load capacity, to speed up and cheapen work conduction, to increase the heat isolating properties of an enclosure structure [1]. In order to create a design method of prefabricated monolithic slab fire-resistance, it's necessary to perform a series of PMS testing, one of which is being described in this article. Subjected to the test is a fragment of prefabricated monolithic slab with polystyrene concrete inserts along the beams with bent metal profile 250 mm thick, with a 2.7 m span loaded with evenly spread load equal to 600 kg/m2. After 3 hour testing for fire-resistance [2] no signs of construction ultimate behavior were detected.

  6. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement

    Science.gov (United States)

    Cao, Wanlin; Zhang, Yongbo; Dong, Hongying; Zhou, Zhongyi; Qiao, Qiyun

    2014-01-01

    Recycled concrete brick (RCB) is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA) and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied. PMID:28788170

  7. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement.

    Science.gov (United States)

    Cao, Wanlin; Zhang, Yongbo; Dong, Hongying; Zhou, Zhongyi; Qiao, Qiyun

    2014-08-19

    Recycled concrete brick (RCB) is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA) and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied.

  8. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement

    Directory of Open Access Journals (Sweden)

    Wanlin Cao

    2014-08-01

    Full Text Available Recycled concrete brick (RCB is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied.

  9. Composite Behavior of a Novel Insulated Concrete Sandwich Wall Panel Reinforced with GFRP Shear Grids: Effects of Insulation Types.

    Science.gov (United States)

    Kim, JunHee; You, Young-Chan

    2015-03-03

    A full-scale experimental program was used in this study to investigate the structural behavior of novel insulated concrete sandwich wall panels (SWPs) reinforced with grid-type glass-fiber-reinforced polymer (GFRP) shear connectors. Two kinds of insulation-expanded polystyrene (EPS) and extruded polystyrene (XPS) with 100 mm thickness were incased between the two concrete wythes to meet the increasing demand for the insulation performance of building envelope. One to four GFRP shear grids were used to examine the degree of composite action of the two concrete wythes. Ten specimens of SWPs were tested under displacement control subjected to four-point concentrated loads. The test results showed that the SWPs reinforced with GFRP grids as shear connectors developed a high degree of composite action resulting in high flexural strength. The specimens with EPS foam exhibited an enhanced load-displacement behavior compared with the specimens with XPS because of the relatively stronger bond between insulation and concrete. In addition, the ultimate strength of the test results was compared to the analytical prediction with the mechanical properties of only GRFP grids. The specimens with EPS insulation presented higher strength-based composite action than the ones with XPS insulation.

  10. Influence of backfill moisture content on the pullout capacity of geotextile reinforcement in MSE walls.

    Science.gov (United States)

    2012-12-01

    Sources of high-quality soils to meet design standards for the construction of reinforced soil structures are : in many cases rare and in short supply. An economical alternative to coarse-grained, free-draining soils : consists of using locally avail...

  11. STUDY OF SINGLE WALLED CARBON NANOTUBE REINFORCED POLYMER COMPOSITES BY HANSEN SOLUBILITY PARAMETERS

    DEFF Research Database (Denmark)

    Ma, Jing

    reinforcement of the polymer by the addition of SWNTs. Existence of agglomerates, voids, and the lower glass transition temperature of epoxy resin, may give the negative effect on the mechanical properties of nanocomposite materials. In the design aspect of the composite material, HSP could help match SWNTs...

  12. Clinical evaluation of prefabricated ceramic inlays

    Directory of Open Access Journals (Sweden)

    H Murali

    2016-01-01

    Full Text Available Background: One of the methods to overcome the problem of polymerization contraction of posterior composites is to use prefabricated ceramic inlays in combination with composites. Several studies have shown that these pre fabricated ceramic inlays act as mega fillers which allow a reduction in resin based composite volume by 50-75% and a concomitant reduction in polymerization shrinkage and marginal micro leakage. Moreover the integration of pre fabricated ceramic inlays into composites reduces the overall coefficient of thermal expansion. Aims and Objectives: The performance of cerena prefabricated inlay system was evaluated. Material and Methods: 20 proximo occlusal cavities were restored with cerana prefabricated inlay system in patients. The performance of cerena pre fabricated inlay system in the oral cavity was recorded at base line follow up using Modified USPHS Ryge criteria at the end of 3, 6, and 12 months. Results: The alpha and Bravo values for the anatomic form, marginal integrity and caries assessment was evaluated. Alpha values were ideal. The Cerena pre- fabricated inlay system showed good fracture resistance, good marginal integrity and maintenance of antomic forms at end of 12 months period. Conclusion: The cerena pre-fabricated inlay system is a good treatment modality and provides a good restorative material at the end of 12 months too.

  13. Nuclear power plant piping prefabrication and assembly

    International Nuclear Information System (INIS)

    Schmidt, H.

    1990-01-01

    The piping design for nuclear power plants projects reveals, at the beginning, a modification through the application of new fabrication techniques for prefabrication and assembly. This report presents a fabrication methodology which aims to minimize the fabrication and assembly costs as well as to improve and assure quality. (Author) [es

  14. Contribution to the understanding of the behaviour of reinforced concrete shear walls under seismic loading: contribution of experiment and modeling to the design

    International Nuclear Information System (INIS)

    Ile, N.

    2000-12-01

    This thesis deals with aspects of seismic behaviour of reinforced concrete shear walls (RCSW). Its objective is to introduce a useful modelling approach for addressing the non-linear response of a large variety of RCSW and to identify several aspects in which this numerical approach could be implemented into design applications. Firstly, the characteristics of the behaviour of RCSW under seismic loading, some design principles and different modelling approaches are discussed. As an important lack of knowledge in several fields was identified, it was considered that three types of shear walls deserve more attention: slightly reinforced slender walls; U-shaped walls and heavily reinforced squat shear walls. A local modelling approach is adopted and the material constitutive models are described in details. Secondly, the behaviour of the two mock-up, CAMUS I and II, tested on the shaking-table during the CAMUS programme, which are slightly reinforced and designed according to the French code PS92 is simulated using a 2-D finite element model (FEM). For comparison purposes, the case of the CAMUS III mock-up, designed according to EC8, is considered. We are then dealing with the case of U-shaped walls under dynamic and cyclic loading. The results obtained from numerical simulations, based on a 3-D shell FEM, are compared with those obtained from tests carried out in the frame of the ICONS programme. Finally, the numerical model is applied to the case of heavily reinforced squat shear walls (similar to those used in the nuclear power plant buildings) subjected to shear loading. A 2-D FEM is considered in order to simulate the behaviour of three different walls, which were tested pseudo-dynamically during the SAFE programme. The results from both experimental and numerical studies are compared and discussed. The most important factors affecting the behaviour of RCSW are highlighted. Different examples of possible contributions to design are presented. (author)

  15. Post-cracking behavior of blocks, prisms, and small concrete walls reinforced with plant fiber

    OpenAIRE

    Soto, I. I.; Ramalho, M. A.; Izquierdo, O. S.

    2013-01-01

    Structural masonry using concrete blocks promotes the rationalization of construction projects, lowering the final cost of a building through the elimination of forms and the reduction of the consumption of reinforcement bars. Moreover, production of a block containing a combination of concrete and vegetable fiber sisal results in a unit with properties such as mechanical strength, stiffness, flexibility, ability to absorb energy, and post-cracking behavior that are comparable to those of a b...

  16. Prefabrication in Building Construction: A Perspective of Pakistan Construction Industry

    Directory of Open Access Journals (Sweden)

    Nafees Ahmed Memon

    2014-07-01

    Full Text Available Construction industry is facing many problems in terms of construction waste, quality, environment, durability, safety and higher construction cost. Adoption of prefabrication is a possible solution to such problems. Accordingly, there is a need to study the prospects that would stimulate the appropriate discussion of the suitability of prefabrication and other construction methods for concrete buildings. Therefore, this study investigates the significance of advantages in adopting prefabrication along with hindrances through questionnaire survey. The data has been analyzed using RIW (Relative Importance Weight method as a MCDM approach. The results depict that main advantages of prefabrication are ?Shorter construction time? and ?Less construction site waste?. The top hindrances in adopting prefabrication as identified in this study are: ?Higher initial construction cost? and ?Inflexible for design changes?. Based on the survey results and apparent progress in the adoption of prefabrication around the world, it is concluded that the use of prefabrication is likely to increase in developing countries like Pakistan

  17. Prefabrication in building construction: a perspective of pakistan construction industry

    International Nuclear Information System (INIS)

    Memon, N.A.; Memon, F.A.; Khehro, S.H.

    2014-01-01

    Construction industry is facing many problems in terms of construction waste, quality, environment, durability, safety and higher construction cost. Adoption of prefabrication is a possible solution to such problems. Accordingly, there is a need to study the prospects that would stimulate the appropriate discussion of the suitability of prefabrication and other construction methods for concrete buildings. Therefore, this study investigates the significance of advantages in adopting prefabrication along with hindrances through questionnaire survey. The data has been analyzed using RIW (Relative Importance Weight) method as a MCDM approach. The results depict that main advantages of prefabrication are Shorter construction time and Less construction site waste. The top hindrances in adopting prefabrication as identified in this study are: Higher initial construction cost and Inflexible for design changes. Based on the survey results and apparent progress in the adoption of prefabrication around the world, it is concluded that the use of prefabrication is likely to increase in developing countries like Pakistan. (author)

  18. Crystallization and melting behavior of multi-walled carbon nanotube-reinforced nylon-6 composites

    NARCIS (Netherlands)

    Phang, In Yee; Ma, Jianhua; Shen, Lu; Liu, Tianxi; Zhang, Wei-De

    2006-01-01

    The crystallization and melting behavior of neat nylon-6 (PA6) and multi-walled carbon nanotubes (MWNTs)/PA6 composites prepared by simple melt-compounding was comparatively studied. Differential scanning calorimetry (DSC) results show two crystallization exotherms (TCC, 1 and TCC, 2) for PA6/MWNTs

  19. Analysis of interlaminar fracture toughness and damage mechanisms in composite laminates reinforced with sprayed multi-walled carbon nanotubes

    KAUST Repository

    Almuhammadi, Khaled; Alfano, Marco; Yang, Yang; Lubineau, Gilles

    2014-01-01

    The present work is focused on the nanoreinforcement of prepreg based carbon fiber composite laminates to improve delamination resistance. Functionalized multi-walled carbon nanotubes (MWCNTs) were dispersed over the interface between prepreg layers through solvent spraying and the resulting mode I interlaminar fracture toughness was determined. For comparison, baseline samples with neat prepregs were also prepared. Results indicate that the introduction of functionalized MWCNTs can favorably affect the interlaminar fracture toughness, and the associated mechanisms of failure have been investigated. The manufacturing procedures and the interfacial reinforcing mechanism were explored by analyzing (i) the wettability between CNTs-solvent solution and prepreg surface, (ii) CNTs dispersion and (iii) the fractured surfaces through high resolution scanning electron microscopy and Raman mapping. © 2013 Elsevier Ltd.

  20. Application of the Hybrid Simulation Method for the Full-Scale Precast Reinforced Concrete Shear Wall Structure

    Directory of Open Access Journals (Sweden)

    Zaixian Chen

    2018-02-01

    Full Text Available The hybrid simulation (HS testing method combines physical test and numerical simulation, and provides a viable alternative to evaluate the structural seismic performance. Most studies focused on the accuracy, stability and reliability of the HS method in the small-scale tests. It is a challenge to evaluate the seismic performance of a twelve-story pre-cast reinforced concrete shear-wall structure using this HS method which takes the full-scale bottom three-story structural model as the physical substructure and the elastic non-linear model as the numerical substructure. This paper employs an equivalent force control (EFC method with implicit integration algorithm to deal with the numerical integration of the equation of motion (EOM and the control of the loading device. Because of the arrangement of the test model, an elastic non-linear numerical model is used to simulate the numerical substructure. And non-subdivision strategy for the displacement inflection point of numerical substructure is used to easily realize the simulation of the numerical substructure and thus reduce the measured error. The parameters of the EFC method are calculated basing on analytical and numerical studies and used to the actual full-scale HS test. Finally, the accuracy and feasibility of the EFC-based HS method is verified experimentally through the substructure HS tests of the pre-cast reinforced concrete shear-wall structure model. And the testing results of the descending stage can be conveniently obtained from the EFC-based HS method.

  1. Thermal characteristics of carbon fiber reinforced epoxy containing multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Jin-woo Lee

    2018-06-01

    Full Text Available The material with irregular atomic structures such as polymer material exhibits low thermal conductivity because of the complex structural properties. Even materials with same atomic configurations, thermal conductivity may be different based on their structural properties. It is expected that nanoparticles with conductivity will change non-conductive polymer base materials to electrical conductors, and improve the thermal conductivity even with extremely small filling amount. Nano-composite materials contain nanoparticles with a higher surface ratio which makes the higher interface percentage to the total surface of nanoparticles. Therefore, thermal resistance of the interface becomes a dominating factor determines the effective thermal conductivity in nano-composite materials. Carbon fiber has characteristic of resistance or magnetic induction and Also, Carbon nanotube (CNT has electronic and thermal property. It can be applied for heating system. These characteristic are used as heating composite. In this research, the exothermic characteristics of Carbon fiber reinforced composite added CNT were evaluated depend on CNT length and particle size. It was found that the CNT dispersed in the resin reduces the resistance between the interfaces due to the decrease in the total resistance of the heating element due to the addition of CNTs. It is expected to improve the life and performance of the carbon fiber composite material as a result of the heating element resulting from this paper. Keywords: Carbon Nanotube (CNT, Carbon Fiber Reinforcement Plastic (CFRP, Heater, Exothermic characteristics

  2. Power, heat and cooling by intelligent prefabricated components from concretes; Strom, Waerme und Kuehlung mit intelligenten Fertigteilen aus Beton

    Energy Technology Data Exchange (ETDEWEB)

    Riffel, Siegfried [HeidelbergCement AG, Talheim (Germany). Entwicklung und Anwendung

    2006-10-15

    Starting of present ecological and economical requirements to buildings renewable energy sources like photovoltaics and solar power will play an important role in future as also change construction engineering and architecture of city design till into detail. The existing contribution presents an innovative result for a massive roof- and wall system from prefabricated concrete components with integrated solar collectors and PV modules. (GL)

  3. Load carrying capacity of shear wall t-connections reinforced with high strength wire ropes

    DEFF Research Database (Denmark)

    Jørgensen, Henrik B.; Bryndom, Thor; Larsen, Michael

    2016-01-01

    -friendly solution. The wire ropes have no bending stiffness and therefore allow for an easier vertical installation of the wall elements. During the last 10 – 15 years, a number of shear tests on plane wire rope connections have been carried out. However, to the best knowledge of the authors, tests on wire rope......Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction...... connections for assembly of precast elements in different planes, such as T- and L-connections, have not yet been published. This paper presents the results of a large test series recently conducted at the University of Southern Denmark to study the shear behaviour of high strength wire rope T...

  4. Load Carrying Capacity of Shear Wall T-Connections Reinforced with High Strength Wire Ropes

    DEFF Research Database (Denmark)

    Jørgensen, Henrik Brøner; Bryndum, Thor; Larsen, Michael

    2017-01-01

    Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction-friendly so......Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction......-friendly solution. The wire ropes have no bending stiffness and therefore allow for an easier vertical installation of the wall elements. During the last 10 – 15 years, a number of shear tests on plane wire rope connections have been carried out. However, to the best knowledge of the authors, tests on wire rope...... connections for assembly of precast elements in different planes, such as T- and L-connections, have not yet been published. This paper presents the results of a large test series recently conducted at the University of Southern Denmark to study the shear behaviour of high strength wire rope T...

  5. The pre-fabrication of building facades

    CERN Document Server

    Rangel, Bárbara; Faria, José

    2017-01-01

    This book compares two buildings with different technologies and distinct environment from the combined viewpoints of civil engineering and architecture. The first is the most recent building of Columbia University in New York, the Northwest Science Building, a project designed by Rafael Moneo and Dan Brodkin of Ove Arup. The second one is the Burgo Tower in Oporto, by Eduardo Souto Moura and Rui Furtado of AFA, a building that brings a new perspective to the use of prefabrication technologies with local traditional construction systems. With the detailed analyses of recognized researchers in civil engineering and architecture, this book is a reflection upon the problems and solutions in the design and construction process of a prefabricated building system. This volume, like those to follow, brings together, building research and building design practice to enhance the knowledge of complementarity areas involved in construction, engineering and architecture. This is the first book in a new series "Building R...

  6. Electrospinning of single wall carbon nanotube reinforced aligned fibrils and yarns

    Science.gov (United States)

    Lam, Hoa Le

    Commercial carbon fibers produced from a polyacrylonitrile (PAN) precursor have reached their performance limit. The approach in this study involves the use of single carbon nanotubes (SWNT) with an ultra-high elastic modulus of approximately ˜1 TPa and tensile strength of ˜37 GPa at a breaking strain of ˜6% to reinforce PAN. In order to translate these extraordinary properties to a higher order structure, the need for a media to carry and assemble the SWNT into continuous fibers or yarns is necessary. Effective translation of properties can only be achieved through uniform distribution of SWNT and their alignment in the fiber axis. This has been one of the major challenges since SWNTs tend to agglomerate due to high van der Waals attraction between tubes. It is the goal of this study to develop dispersion technique(s) for the SWNT and process them into aligned fibers utilizing the electrospinning process. The electrospun nanofibers were then characterized by various techniques such as ESEM, Raman microspectroscopy, HRTEM, and tensile testing. Composite nanofibers containing various contents of SWNT up to 10 wt. % with diameter ranging from 40--300 nm were successfully electrospun through varying the polymer concentration and spinning parameters. The inclusion of SWNTs and their alignment in the fiber axis were confirmed by Raman microspectroscopy, polarized Raman and HRETEM. The failure mechanism of the nanofibers was investigated by HRTEM through fiber surface fracture. A two stage rupture mechanism was observed where crazing initiates at a surface defect followed by SWNTs pulling out of the PAN matrix. Such mechanisms consume energy therefore strengthening and toughening the fibers. Mechanical drawing of the fiber prior to heat treatment induced molecular orientation resulting in oriented graphite layers in the carbonized fibers. This study has established a processing base and characterization techniques to support the design and development of SWNT

  7. Synthesis of high quality single-walled carbon nanotubes via a catalytic layer reinforced by self-assembled monolayers

    International Nuclear Information System (INIS)

    Adhikari, Prashanta Dhoj; Song, Wooseok; Cha, Myoung-Jun; Park, Chong-Yun

    2013-01-01

    This work reports the synthesis of high quality single-walled carbon nanotubes (SWCNT) using a catalytic layer reinforced by self-assembled monolayers (SAM). Amine-SAM was introduced on a SiO 2 /Si substrate and then an iron nanoparticles solution was dropped on the substrate by spin-coating. This catalytic template was used to grow carbon nanotubes by chemical vapor deposition and the synthesized SWCNT were observed to be prominent, based on the size distribution. Highly dense SWCNT with a diameter of about 1.1-1.2 nm were produced at 800-850 °C. Moreover, the diameter distribution of the SWCNT was more selective at a growth temperature of 900 °C. These findings provide important insights for a SAM support layer that can play the role as a restriction for the agglomeration of iron catalyst and is promising for the synthesis of high quality SWCNT. - Highlights: • Fe nanoparticles on self-assembled monolayers (SAM) containing template is underlined. • Its catalytic behavior to synthesis single-walled carbon nanotubes is studied. • The role of SAM on catalytic template is explored

  8. Finite element elasto-plastic analysis of thin walled structures of reinforced concrete as applied to reactor facilities

    International Nuclear Information System (INIS)

    Fujita, F.; Tsuboi, Y.

    1981-01-01

    The authors developed a new program of elasto-plastic analysis of reinforced concrete shells, in which the simplest model of shell element and an orthotropic constitutive relation are adopted, and verified its validity with reference to the results of model experiments of containers and box-wall structures with various loading conditions. For the two-dimensional stress-strain relationship of concrete, an orthotropic nonlinear formula proposed by one of the authors was adopted. For concrete, the octahedral shear failure and tension cut-off criteria were also imposed. The Kirchhoff-Love's assumptions were assumed to be valid for the whole range of the analysis and the layered approach of elasto-plastic stiffness evaluation. Derivation of the shell element is outlined with examination of its accuracy in elastic range and the assumption of elasto-plastic material property and the procedure of nonlinear analysis are described. As examples, the method is applied to the analysis of a cylindrical container and a box-wall structure. Comparison of the computed results with the corresponding experimental data indicates the applicability of the proposed method. (orig./HP)

  9. Analysis of elasto-plasticity of a reinforced framework. Report 4. Framework reinforced by a wing wall made of post-placed concrete; Hokyo honegumi no dansosei kaiseki. 4. Atouchi sodekabe ni yoru hokyo honegumi

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, H. [Japan Testing Center for Construction Materials, Tokyo (Japan); Shimizu, Y. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-09-01

    An elasto-plasticity stress analysis was performed on reinforcement using a wing wall made of post-placed concrete as an anti-earthquake reinforcement method for ferro-concrete structures. The analytical values were compared with experimental values, and discussions were given on reasonability of the analytic method. Wing walls made of post-placed concrete were inserted into a three-layered single-spanned model of a reinforced framework made of reinforced mortar (the wing walls being three kinds comprising 1/4 span portion in the first layer, and 1/4 portions in the first and second layers). With the columns loaded and retained with an axial force of 3 tf, a horizontal force was applied from one direction under an assumption that the force forms a uniform distribution. The analysis model was permuted with a wire material having one nodal point and three degrees of freedom as has been reported in the previous paper. The model was divided into the wing wall and the column, and the wing wall portion was permuted into a brace having pins at both ends so that the brace has the withstand strength equivalent to that of the wing wall. A tri-linear type or a bi-linear type was hypothesized for restoring force characteristics of each portion. According to the analytical result, the analytical values agreed relatively well with the experimental values in the load-deformation relationship and fracture conditions, verifying the reasonability of the analytical hypothesis. 5 refs., 5 figs., 3 tabs.

  10. Reliability assessment and probability based design of reinforced concrete containments and shear walls

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Ellingwood, B.; Shinozuka, M.

    1986-03-01

    This report summarizes work completed under the program entitled, ''Probability-Based Load Combinations for Design of Category I Structures.'' Under this program, the probabilistic models for various static and dynamic loads were formulated. The randomness and uncertainties in material strengths and structural resistance were established. Several limit states of concrete containments and shear walls were identified and analytically formulated. Furthermore, the reliability analysis methods for estimating limit state probabilities were established. These reliability analysis methods can be used to evaluate the safety levels of nuclear structures under various combinations of static and dynamic loads. They can also be used to generate analytically the fragility data for PRA studies. In addition to the development of reliability analysis methods, probability-based design criteria for concrete containments and shear wall structures have also been developed. The proposed design criteria are in the load and resistance factor design (LRFD) format. The load and resistance factors are determined for several limit states and target limit state probabilities. Thus, the proposed design criteria are risk-consistent and have a well-established rationale. 73 refs., 18 figs., 16 tabs

  11. The Application of Buckling Reinforced Bracing and Shear Wall in Retrofitting of Existing Concrete Building

    Directory of Open Access Journals (Sweden)

    Mahdi Izadi

    2015-06-01

    Full Text Available Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained different rehabilitation systems. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. Several retrofitting techniques such as addition masonry infill wall, application of buckling restrained braces and local modification of components has been studied in order to improve the overall seismic performance of such buildings. In response to many of the practical issues and economic considerations, engineers use often convergent unbuckling steel bracing frames as the lateral load resisting system during an earthquake.This kind of bracings increases the hardness and strength of concrete structures.The aim of the present study is the evaluation and comparison of seismic performance and retrofitting of an existing 7-storeys concrete structure with buckling restrained bracings and shear walls by nonlinear static procedure (NSP and accordance with cod-361. The results show that the buckling restrained bracing, decreased drift to acceptable levels and Structure behaves on the life safety of performance level.

  12. Substructure hybrid testing of reinforced concrete shear wall structure using a domain overlapping technique

    Science.gov (United States)

    Zhang, Yu; Pan, Peng; Gong, Runhua; Wang, Tao; Xue, Weichen

    2017-10-01

    An online hybrid test was carried out on a 40-story 120-m high concrete shear wall structure. The structure was divided into two substructures whereby a physical model of the bottom three stories was tested in the laboratory and the upper 37 stories were simulated numerically using ABAQUS. An overlapping domain method was employed for the bottom three stories to ensure the validity of the boundary conditions of the superstructure. Mixed control was adopted in the test. Displacement control was used to apply the horizontal displacement, while two controlled force actuators were applied to simulate the overturning moment, which is very large and cannot be ignored in the substructure hybrid test of high-rise buildings. A series of tests with earthquake sources of sequentially increasing intensities were carried out. The test results indicate that the proposed hybrid test method is a solution to reproduce the seismic response of high-rise concrete shear wall buildings. The seismic performance of the tested precast high-rise building satisfies the requirements of the Chinese seismic design code.

  13. Thermal characteristics of carbon fiber reinforced epoxy containing multi-walled carbon nanotubes

    Science.gov (United States)

    Lee, Jin-woo; Park, Soo-Jeong; Kim, Yun-hae; Riichi-Murakami

    2018-06-01

    The material with irregular atomic structures such as polymer material exhibits low thermal conductivity because of the complex structural properties. Even materials with same atomic configurations, thermal conductivity may be different based on their structural properties. It is expected that nanoparticles with conductivity will change non-conductive polymer base materials to electrical conductors, and improve the thermal conductivity even with extremely small filling amount. Nano-composite materials contain nanoparticles with a higher surface ratio which makes the higher interface percentage to the total surface of nanoparticles. Therefore, thermal resistance of the interface becomes a dominating factor determines the effective thermal conductivity in nano-composite materials. Carbon fiber has characteristic of resistance or magnetic induction and Also, Carbon nanotube (CNT) has electronic and thermal property. It can be applied for heating system. These characteristic are used as heating composite. In this research, the exothermic characteristics of Carbon fiber reinforced composite added CNT were evaluated depend on CNT length and particle size. It was found that the CNT dispersed in the resin reduces the resistance between the interfaces due to the decrease in the total resistance of the heating element due to the addition of CNTs. It is expected to improve the life and performance of the carbon fiber composite material as a result of the heating element resulting from this paper.

  14. The Effect of Shear Wall Distribution on the Dynamics of Reinforced Concrete Structures

    Science.gov (United States)

    Helou, S. H.; Touqan, A. R.

    2008-07-01

    The inclusion of a soft storey in multistory concrete buildings is a feature gaining popularity in urban areas where land is of exorbitant cost. In earthquake prone zones, this feature has been observed in post earthquake investigations. Although engineers are prepared to accept the notion that a soft storey poses a weak link in Seismic Design, yet the idea demands better understanding. The following study illustrates the importance of the judicious distribution of shear walls. The selected building is analyzed through nine numerical models which address the behavior of framed structures. The parameters discussed include, inter alias, the fundamental period of vibration, lateral displacements, axial and shear forces. It is noticed that an abrupt change in stiffness between the soft storey and the level above is responsible for increasing the strength demand on first storey columns. Extending the elevator shafts throughout the soft storey is strongly recommended.

  15. The Effect of Shear Wall Distribution on the Dynamics of Reinforced Concrete Structures

    International Nuclear Information System (INIS)

    Helou, S. H.; Touqan, A. R.

    2008-01-01

    The inclusion of a soft storey in multistory concrete buildings is a feature gaining popularity in urban areas where land is of exorbitant cost. In earthquake prone zones, this feature has been observed in post earthquake investigations. Although engineers are prepared to accept the notion that a soft storey poses a weak link in Seismic Design, yet the idea demands better understanding. The following study illustrates the importance of the judicious distribution of shear walls. The selected building is analyzed through nine numerical models which address the behavior of framed structures. The parameters discussed include, inter alias, the fundamental period of vibration, lateral displacements, axial and shear forces. It is noticed that an abrupt change in stiffness between the soft storey and the level above is responsible for increasing the strength demand on first storey columns. Extending the elevator shafts throughout the soft storey is strongly recommended

  16. Controlled nanostructure and high loading of single-walled carbon nanotubes reinforced polycarbonate composite

    International Nuclear Information System (INIS)

    Wang Shiren; Liang Zhiyong; Pham, Giang; Park, Young-Bin; Wang, Ben; Zhang, Chuck; Kramer, Leslie; Funchess, Percy

    2007-01-01

    This paper presents an effective technique to fabricate thermoplastic nanocomposites with high loading of well-dispersed single-walled carbon nanotubes (SWNTs). SWNT membranes were made from a multi-step dispersion and filtration method, and then impregnated with polycarbonate solution to make thermoplastic nanocomposites. High loading of nanotubes was achieved by controlling the viscosity of polycarbonate solution. SEM and AFM characterization results revealed the controlled nanostructure in the resultant nanocomposites. Dynamic mechanical property tests indicated that the storage modulus of the resulting nanocomposites at 20 wt% nanotubes loading was improved by a factor of 3.4 compared with neat polycarbonate material. These results suggest the developed approach is an effective way to fabricate thermoplastic nanocomposites with good dispersion and high SWNT loading

  17. Reinforcement of single-walled carbon nanotube bundles by intertube bridging

    Science.gov (United States)

    Kis, A.; Csányi, G.; Salvetat, J.-P.; Lee, Thien-Nga; Couteau, E.; Kulik, A. J.; Benoit, W.; Brugger, J.; Forró, L.

    2004-03-01

    During their production, single-walled carbon nanotubes form bundles. Owing to the weak van der Waals interaction that holds them together in the bundle, the tubes can easily slide on each other, resulting in a shear modulus comparable to that of graphite. This low shear modulus is also a major obstacle in the fabrication of macroscopic fibres composed of carbon nanotubes. Here, we have introduced stable links between neighbouring carbon nanotubes within bundles, using moderate electron-beam irradiation inside a transmission electron microscope. Concurrent measurements of the mechanical properties using an atomic force microscope show a 30-fold increase of the bending modulus, due to the formation of stable crosslinks that effectively eliminate sliding between the nanotubes. Crosslinks were modelled using first-principles calculations, showing that interstitial carbon atoms formed during irradiation in addition to carboxyl groups, can independently lead to bridge formation between neighbouring nanotubes.

  18. Exploring the beliefs of Australian prefabricated house builders

    Directory of Open Access Journals (Sweden)

    Dale A Steinhardt

    2016-06-01

    Full Text Available The housing sector accounts for a majority of newly constructed buildings. Prefabrication, defined as the factory construction of houses or significant components, is widely promoted as a means to improve efficiency. This paper focuses on the research questions: RQ1. What are the attitudes of builders towards prefabrication adoption? RQ2. What types of stakeholders do builders believe influence their adoption decisions? RQ3. What types of contextual influences do builders believe impact their adoption decisions? Current prefabrication research has focused on the advantages and disadvantages of prefabrication, without further unpacking the beliefs of stakeholders that underpin them. This paper addresses this gap and increases the understanding of beliefs that can frame interventions to increase the market penetration of prefabrication. Fourteen interviews with Australian prefabricators were undertaken as a Belief Elicitation Study. This qualitative methodology is framed by the Theory of Planned Behaviour (TPB and the Technology Acceptance Model (TAM. Results show that modern high-quality prefabricated housing has struggled to overcome historical stigma; improved construction speed has not and is not likely to translate to reduced totals costs for a majority of firms; and prefabrication adoption has been hindered by an almost completely unsupportive industry infrastructure. Recommendations are made to frame arguments in improving short-term outcomes for an industry driven by practical considerations. Future discourse must focus on cost impacts, financial security and risk reduction. Establishing networks of prefabricators that can build a strong, unified voice for the industry should be prioritised.

  19. A More Realistic Lateral Load Pattern for Design of Reinforced Concrete Buildings with Moment Frames and Shear Walls

    International Nuclear Information System (INIS)

    Hosseini, Mahmood; Khosahmadi, Arash

    2008-01-01

    In this research it has been tried to find a more realistic distribution pattern for the seismic load in reinforced concrete (R/C) buildings, having moment frames with shear walls as their lateral resisting system, by using Nonlinear Time History Analyses (NLTHA). Having shear wall as lateral load bearing system decreases the effect of infill walls in the seismic behavior of the building, and therefore the case of buildings with shear walls has been considered for this study as the first stage of the studies on lateral load patterns for R/C buildings. For this purpose, by assuming three different numbers of bays in each direction and also three different numbers of stories for the buildings, several R/C buildings, have been studied. At first, the buildings have been designed by the Iranian National Code for R/C Buildings. Then they have been analyzed by a NLTHA software using the accelerograms of some well-known earthquakes. The used accelerograms have been also scaled to various levels of peak ground acceleration (PGA) such as 0.35 g, 0.50 g, and 0.70 g, to find out the effect of PGA in the seismic response. Numerical results have shown that firstly the values of natural period of the building and their shear force values, calculated by the code, are not appropriate in all cases. Secondly, it has been found out that the real lateral load pattern is quite different with the one suggested by the seismic code. Based on the NLTHA results a new lateral load pattern has been suggested for this kind of buildings, in the form of some story-dependent modification factors applied to the existing code formula. The effects of building's natural period, as well as its number of stories, are taken into account explicitly in the proposed new load pattern. The proposed load pattern has been employed to redesign the buildings and again by NLTHA the real lateral load distribution in each case has been obtained which has shown very good agreement with the proposed pattern

  20. Multi-walled carbon nanotube-reinforced porous iron oxide as a superior anode material for lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Xin-Jing; Zhang, Juan; Qi, Gong-Wei; Dai, Xiao-Hui; Zhou, Jun-Ping [School of Chemistry and Chemical Engineering, Shandong University, No. 27, Shanda Nan Rd., Jinan 250100 (China); Zhang, Shu-Yong, E-mail: syzhang@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, No. 27, Shanda Nan Rd., Jinan 250100 (China); National Key Lab of Crystal, Shandong University, No. 27, Shanda Nan Rd., Jinan 250100 (China)

    2015-08-15

    Highlights: • Electrochemical performance of Fe{sub 3}O{sub 4} is improved by combining different approaches. • Porous Cu substrate is used to enlarge surface area and improve conductivity. • MWCNT is used to reinforce the electrode structure and change morphology of Fe{sub 3}O{sub 4}. • Reversible capacity, capacity retention and high-rate performance are improved. - Abstract: Multi-walled carbon nanotube-reinforced porous iron oxide (Fe{sub 3}O{sub 4}/MWCNT) is synthesized by a two-step approach with porous Cu substrate serving as current collector. Porous Cu substrate is prepared through electroless deposition with hydrogen bubble serving as template. Fe{sub 3}O{sub 4}/MWCNT composites are prepared by the electrodeposition of Fe{sub 3}O{sub 4} in the presence of dispersed MWCNTs from a Fe{sub 2}(SO{sub 4}){sub 3} solution with MWCNT suspension. Results showed that Fe{sub 3}O{sub 4} forms granular nanoparticles on the porous Cu substrate with several MWCNTs embedded in it. Adding MWCNTs changes the morphology of Fe{sub 3}O{sub 4}. Smooth Fe{sub 3}O{sub 4}, smooth Fe{sub 3}O{sub 4}/MWCNT, and porous Fe{sub 3}O{sub 4} composites are also prepared for comparison. When used as anode materials, porous Fe{sub 3}O{sub 4}/MWCNT composites have a reversible capacity of approximately 601 mA h g{sup −1} at the 60th cycle at a cycling rate of 100 mA g{sup −1}. This value is higher than that of the other materials. The reversible capacity at a cycling rate of 10,000 mA g{sup −1} is approximately 50% of that at 100 mA g{sup −1}. Therefore, the MWCNT-reinforced porous Fe{sub 3}O{sub 4} composite exhibits much better reversible capacity, capacity retention, and high-rate performance than the other samples. This finding can be ascribed to the porous structure of Fe{sub 3}O{sub 4}, better conductivity of porous Cu substrate and MWCNTs, and the morphology change of Fe{sub 3}O{sub 4} nanoparticles upon the addition of MWCNTs.

  1. Twin-screw extrusion of multi walled carbon nanotubes reinforced polycarbonate composites: Investigation of electrical and mechanical properties

    International Nuclear Information System (INIS)

    Mack, C; Sathyanarayana, S; Weiss, P; Mikonsaari, I; Hübner, C; Henning, F; Elsner, P

    2012-01-01

    1, 3 and 5 wt.% multi walled carbon nanotubes (MWCNT) reinforced polycarbonate (PC) composites were processed in a twin-screw extruder (L/D=52) with two different screw speeds, throughputs and screw configurations. Extruded strands were characterized for dispersion and measurement of electrical resistivities while the pelletized extrudates were injection molded to produce samples for mechanical and further electrical property measurements. The absolute resistance of the melt was recorded with an online melt resistance setup developed by our group. The volume resistivity of pure PC (10 17 Ω.m) was lowered to 10 4 − 10 5 Ω.m on an injection molded PC-1 wt. % MWCNT composite. 3 wt.% MWCNT incorporated composites showed volume resistivity less than 1 Ω.m independent of process conditions. At lower filler contents the volume resistivity of injection molded samples were higher than those observed on the extruded strands and this effect diminished with increasing MWCNT loadings; owing to the loss of CNT network contacts due to shear induced filler orientation and core-skin effects. The quality of dispersion was exceptional for all filler concentrations at any process condition owing to the affinity of MWCNT towards PC due to the lower interfacial energy difference between the reactants and high polarity of PC. The modulus and strength of the composites increased with filler addition, however at 5 wt.% filler loading the strength of the composites processed with lower SMEs was less than that observed on the 1 wt.% MWCNT reinforced PC composite. The elongation of the composites at maximum tensile strength were comparable to that of neat PC except for composites with 5 wt.% MWCNT loading processed with lower SMEs. Composites with identical filler loadings which were processed with higher SMEs showed higher notched impact strength values principally because of the ability of very well dispersed filler fractions to inhibit crack propagation. The significance of the

  2. Development of multi-walled carbon nanotubes reinforced monetite bionanocomposite cements for orthopedic applications

    International Nuclear Information System (INIS)

    Boroujeni, Nariman Mansoori; Zhou, Huan; Luchini, Timothy J.F.; Bhaduri, Sarit B.

    2013-01-01

    In this study, we present results of our research on biodegradable monetite (DCPA, CaHPO 4 ) cement with surface-modified multi-walled carbon nanotubes (mMWCNTs) as potential bone defect repair material. The cement pastes showed desirable handling properties and possessed a suitable setting time for use in surgical setting. The incorporation of mMWCNTs shortened the setting time of DCPA and increased the compressive strength of DCPA cement from 11.09 ± 1.85 MPa to 21.56 ± 2.47 MPa. The cytocompatibility of the materials was investigated in vitro using the preosteoblast cell line MC3T3-E1. An increase of cell numbers was observed on both DCPA and DCPA-mMWCNTs. Scanning electron microscopy (SEM) results also revealed an obvious cell growth on the surface of the cements. Based on these results, DCPA-mMWCNTs composite cements can be considered as potential bone defect repair materials. - Highlights: • A monetite bone cement for orthopedic applications is reported. • Incorporation of MWCNTs into monetite bone cement is discussed. • Surface functionalized MWCNTs can improve the mechanical strength of monetite cement. • MWCNTs have no impacts on the cytocompatibility of monetite cements

  3. Development of multi-walled carbon nanotubes reinforced monetite bionanocomposite cements for orthopedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Boroujeni, Nariman Mansoori [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Zhou, Huan, E-mail: Huan.Zhou@Rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Luchini, Timothy J.F. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Division of Dentistry, The University of Toledo, Toledo, OH (United States)

    2013-10-15

    In this study, we present results of our research on biodegradable monetite (DCPA, CaHPO{sub 4}) cement with surface-modified multi-walled carbon nanotubes (mMWCNTs) as potential bone defect repair material. The cement pastes showed desirable handling properties and possessed a suitable setting time for use in surgical setting. The incorporation of mMWCNTs shortened the setting time of DCPA and increased the compressive strength of DCPA cement from 11.09 ± 1.85 MPa to 21.56 ± 2.47 MPa. The cytocompatibility of the materials was investigated in vitro using the preosteoblast cell line MC3T3-E1. An increase of cell numbers was observed on both DCPA and DCPA-mMWCNTs. Scanning electron microscopy (SEM) results also revealed an obvious cell growth on the surface of the cements. Based on these results, DCPA-mMWCNTs composite cements can be considered as potential bone defect repair materials. - Highlights: • A monetite bone cement for orthopedic applications is reported. • Incorporation of MWCNTs into monetite bone cement is discussed. • Surface functionalized MWCNTs can improve the mechanical strength of monetite cement. • MWCNTs have no impacts on the cytocompatibility of monetite cements.

  4. The Design of a Semi-Prefabricated LVL-Concrete Composite Floor

    Directory of Open Access Journals (Sweden)

    David Yeoh

    2012-01-01

    Full Text Available This paper describes the design of a novel semi-prefabricated LVL-concrete composite floor that has been developed in New Zealand. In this solution, the floor units made from LVL joists and plywood are prefabricated in the factory and transported to the building site. The units are then lifted onto the supports and connected to the main frames of the building and to the adjacent units. Finally, a concrete topping is poured on top of the units in order to form a continuous slab connecting all the units. Rectangular notches cut from the LVL joists and reinforced with coach screws provide the composite action between the concrete slab and the LVL joists. This system proved to be an effective modular solution that ensures rapid construction. A design procedure based on the use of the effective flexural stiffness method, also known as the “gamma method” is proposed for the design of the composite floor at ultimate and serviceability limit states, in the short and long term. By comparison with the experimental results, it is shown that the proposed method leads to conservative design. A step-by-step design worked example of this novel semi-prefabricated composite floor concludes the paper.

  5. Micromechanical characterization of single-walled carbon nanotube reinforced ethylidene norbornene nanocomposites for self-healing applications

    International Nuclear Information System (INIS)

    Aïssa, B; Haddad, E; Jamroz, W; Hassani, S; Farahani, R D; Therriault, D; Merle, P G

    2012-01-01

    We report on the fabrication of self-healing nanocomposite materials, consisting of single-walled carbon nanotube (SWCNT) reinforced 5-ethylidene-2-norbornene (5E2N) healing agent—reacted with ruthenium Grubbs catalyst—by means of ultrasonication, followed by a three-roll mixing mill process. The kinetics of the 5E2N ring opening metathesis polymerization (ROMP) was studied as a function of the reaction temperature and the SWCNT loads. Our results demonstrated that the ROMP reaction was still effective in a large temperature domain ( − 15–45 °C), occurring at very short time scales (less than 1 min at 40 °C). On the other hand, the micro-indentation analysis performed on the SWCNT/5E2N nanocomposite material after its ROMP polymerization showed a clear increase in both the hardness and the Young modulus—up to nine times higher than that of the virgin polymer—when SWCNT loads range only from 0.1 to 2 wt%. The approach demonstrated here opens new prospects for using carbon nanotube and healing agent nanocomposite materials for self-repair functionality, especially in a space environment. (paper)

  6. Analysis of interlaminar fracture toughness and damage mechanisms in composite laminates reinforced with sprayed multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Almuhammadi, Khaled; Alfano, Marco; Yang, Yang; Lubineau, Gilles

    2014-01-01

    Highlights: • CNTs are solvent sprayed on CFRP prepreg to improve interlaminar fracture toughness. • Raman mapping revealed the actual penetration of CNTs across the interface. • A finite thickness nanoreinforced region was able to spread damage through CNT pull-out and peeling. • The induced dissipation mechanisms are operative at the microscale. • The nanoreinforcement strategy led to an increased fracture toughness. - Abstract: The present work is focused on the nanoreinforcement of prepreg based carbon fiber composite laminates to improve delamination resistance. Functionalized multi-walled carbon nanotubes (MWCNTs) were dispersed over the interface between prepreg layers through solvent spraying and the resulting mode I interlaminar fracture toughness was determined. For comparison, baseline samples with neat prepregs were also prepared. Results indicate that the introduction of functionalized MWCNTs can favorably affect the interlaminar fracture toughness, and the associated mechanisms of failure have been investigated. The manufacturing procedures and the interfacial reinforcing mechanism were explored by analyzing (i) the wettability between CNTs-solvent solution and prepreg surface, (ii) CNTs dispersion and (iii) the fractured surfaces through high resolution scanning electron microscopy and Raman mapping

  7. Effectively enhanced load transfer by interfacial reactions in multi-walled carbon nanotube reinforced Al matrix composites

    International Nuclear Information System (INIS)

    Zhou, Weiwei; Yamaguchi, Tatsuya; Kikuchi, Keiko; Nomura, Naoyuki; Kawasaki, Akira

    2017-01-01

    The thermal expansion response of multi-walled carbon nanotube (MWCNT) reinforced Al matrix composites was employed to discuss the improvement of the load transfer at the interface between the MWCNTs and the Al matrix. An aluminum carbide (Al_4C_3) nanostructure at the end of the MWCNTs, incorporated in the Al matrix, was produced by appropriate heat-treatment. The stress contrast around the Al_4C_3 observed in the high-resolution transmission electron microscopy (HRTEM) image revealed the evidence of a trace of friction, which would lead to the enhancement of the anchor effect from the Al matrix. This anchor effect of Al_4C_3 may hinder the local interfacial slippage and constrain the deformation of the Al matrix. As a result, the thermal expansion behavior became linear and reversible under cyclic thermal load. It is concluded that the formation of Al_4C_3 could effectively enhance the load transfer in MWCNT/Al composites. The yield strength of MWCNT/Al composites was substantially increased under the appropriate quantity of Al_4C_3 produced at the MWCNT-Al interface by precisely controlled heat-treatment.

  8. Studies of the Prefabricated Housing Construction Market in Poland

    Science.gov (United States)

    Radziszewska-Zielina, Elżbieta; Gleń, Monika

    2014-11-01

    The directions of development of the construction market are not only related to the need to own one's own home but also to increasing functional and economic requirements and conditions of sustainable development. The perception and understanding of prefabrication in housing construction are undoubtedly starting to change. Sustainable construction criteria may constitute a significant turning point and support for the development of new prefabricated housing construction technologies. Entrepreneurs are slowly perceiving an opportunity for the development of prefabrication in the construction market. The implementation and popularisation of ready-made homes will undoubtedly constitute a favourable change in the Polish construction market; however, this will require a modification of habits. This article presents an historical analysis of the development of the prefabricated housing construction market as well as an attempt to answer questions concerning the future of prefabrication in housing construction in Poland based on the conducted studies.

  9. Experimental study of the leakage rate through cracked reinforced concrete wall elements for defining the functional failure criteria of containment buildings

    International Nuclear Information System (INIS)

    Choun, Young Sun; Cho, Nam So

    2004-01-01

    Containment buildings in nuclear power plants should maintain their structural safety as well as their functional integrity during an operation period. To maintain the functional integrity, the wall and dome of the containment buildings have to maintain their air tightness under extreme loading conditions such as earthquakes, missile impact, and severe accidents. For evaluating the functional failure of containments, it is important to predict the leak amount through cracked concrete walls. The leakage through concrete cracks has been studied since 1972. Buss examined the flow rate of air through a pre-existing crack in a slab under air pressure. Rizkalla el al. initiated an experimental study for the leakage of prestressed concrete building segments under uniaxial and biaxial loadings to simulate the loading condition of containment buildings under an internal pressure. Recently, Salmon el al. initiated an experimental program for determining the leak rates in typical reinforced concrete shear walls subjected to beyond design basis earthquakes. This study investigates the cracking behavior of reinforced concrete containment wall elements under a uniaxial tension and addresses the outline of the leakage test for unlined containment wall elements

  10. Prefabricated Construction using Digitally Integrated Industrial Manufacturing

    Directory of Open Access Journals (Sweden)

    Harry Giles

    2012-10-01

    Full Text Available The paper describes research being carried out in relation to prefabricated high density affordablehousing under a grant from the Partnership for the Advancement of Technology in Housing(PATH and the National Science Foundation (NSF in the USA. The objective is to demonstratehow a new paradigm for the conceptualization and construction of buildings can be conceivedof as an entirely factory based process that creates advantages for construction through industrialsystems technology transfer. Our approach is intended to transform design methodologythrough demonstrating how alternative construction concepts, using entirely pre-manufacturedvolumetric units, can be adopted. This involves digital modeling that facilitates parametric variationsfor creating customized prefabricated products from design conceptualization through tofinal product delivery. The paper discusses key areas under investigation in relation to a manufacturingparadigm used in the automotive industry that integrates virtual prototyping and industrialmanufacturing systems. Our research explores a type of monocoque volumetric unit prefabricatedin steel, which will be pre-finished as part of a modular factory-built approach usingindustrialized methodologies that will facilitate customized manufacture of a high quality energyefficient product for affordable housing.The paper addresses the automotive industry methods of manufacture that have served increasedautomobile performance and economics through mass production for over a century. In starkcontrast, the building industry and in particular the housing industry is still a century behind. It issuggested that a move away from tradition will require an industry wide initiative, just like HenryFord led the way with mass production. By embracing the increasing sophistication and capabilitythat digital technology offers, it is shown how digital tools are implemented towards masscustomization in house design using virtual modeling in the

  11. Physics-Based Simulation and Experiment on Blast Protection of Infill Walls and Sandwich Composites Using New Generation of Nano Particle Reinforced Materials

    Science.gov (United States)

    Irshidat, Mohammad

    A critical issue for the development of nanotechnology is our ability to understand, model, and simulate the behavior of small structures and to make the connection between nano structure properties and their macroscopic functions. Material modeling and simulation helps to understand the process, to set the objectives that could guide laboratory efforts, and to control material structures, properties, and processes at physical implementation. These capabilities are vital to engineering design at the component and systems level. In this research, experimental-computational-analytical program was employed to investigate the performance of the new generation of polymeric nano-composite materials, like nano-particle reinforced elastomeric materials (NPREM), for the protection of masonry structures against blast loads. New design tools for using these kinds of materials to protect Infill Walls (e.g. masonry walls) against blast loading were established. These tools were also extended to cover other type of panels like sandwich composites. This investigation revealed that polymeric nano composite materials are strain rate sensitive and have large amount of voids distributed randomly inside the materials. Results from blast experiments showed increase in ultimate flexural resistance achieved by both unreinforced and nano reinforced polyurea retrofit systems applied to infill masonry walls. It was also observed that a thin elastomeric coating on the interior face of the walls could be effective at minimizing the fragmentation resulting from blast. More conclusions are provided with recommended future research.

  12. Indoor Noise Loading in Residential Prefabricated Buildings

    Science.gov (United States)

    Kraus, Michal; Juhásová Šenitková, Ingrid

    2017-10-01

    Quality on indoor environment is among others also defined by an acoustic comfort and noise emissions. The indoor noise loading in the residential prefabricated buildings is specific problem related to structural design of these buildings. Problems with noise level of sanitary systems are mostly associated with hydraulic shock such as water distribution and sewage drainage. Another very common cause of excessive noise is also flushing the toilet or water fall on enamelled steel (bath or shower). This paper aims to analyse the acoustic properties in the residential prefabricated buildings. Sanitary core of the assessed apartment is in original condition without any alterations. The sanitary core is based on a formica (high-pressure laminate). The study discusses the maximum sound levels in the three assessed rooms for the three different noise sources. The values of maximum noise level are measured for the corridor, bedroom and living room. Sources of noise are common activities relating to the operation of sanitary core - the toilet flush in the toilet, falling water from the shower in the bathroom and the water falling on the bottom of the kitchen sink in the kitchen. Other sources of noise are eliminated or minimized during the experiment. The digital sound level meter Testo 815 is used for measurements. The measured values of maximum sound level LA,max [dB] are adjusted by the correction coefficient. The obtained values are compared with the hygienic limits for day and night period. Night hygienic limit (30 dB) is exceeded in all the rooms for all noise sources. This limit is exceeded from 17 to 73%. The values in the bedroom and the living room meet the daily hygienic limit (40 dB). The daily limit is exceeded only in the corridor. The highest values of noise are identified for the toilet flushing.

  13. Prefabricated Engineered Bamboo Housing for East Africa | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project will endeavor to transfer new bamboo-based prefabricated housing technology from China and India to ... durable, healthy and environmentally friendly houses for the urban poor. ... International Network for Bamboo and Rattan.

  14. Surface decoration of short-cut polyimide fibers with multi-walled carbon nanotubes and their application for reinforcement of lightweight PC/ABS composites

    Science.gov (United States)

    Zhang, Le; Han, Enlin; Wu, Yulun; Wang, Xiaodong; Wu, Dezhen

    2018-06-01

    The surface decoration of short-cut polyimide (PI) fibers with multi-walled carbon nanotubes (MWCNTs) was performed by fabricating a polydopamine (PDA) coating layer on the fiber surface and then immobilizing MWCNTs onto the coating layer via covalent bonding. This successful surface decoration was confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared microscopy and static water contact angle. The application of the surface-decorated PI fibers as reinforcing fibers for reinforcement of polycarbonate (PC)/acrylonitrile-butadiene-styrene copolymer (ABS) alloy was investigated, which indicated that the MWCNTs-decorated PI fibers not only could effectively reinforce the PC/ABS alloy but also generated a significant lightweighting effect on the resulting composites. The maximum mechanical properties were achieved for the composites at a fiber content of 20 wt.% and a fiber length of 3 mm. This significant reinforcement effect is attributed to the enhancement of interaction bonding strength between the fibers and matrix as a result of the surface decoration of PI fibers with MWCNTs. The morphological investigation suggested that fiber rupture was the major energy dissipation mechanism in the tensile and impact failures, whereas fiber debonding and pullout were partly involved in the fracture energy dissipation. In addition, the presence of surface-decorated PI fibers slightly enhanced the thermal stability and load bearing capability of composites. This work can provide a type of high-performance lightweight composite material for automobile and aviation industries.

  15. Capital Cost Optimization for Prefabrication: A Factor Analysis Evaluation Model

    Directory of Open Access Journals (Sweden)

    Hong Xue

    2018-01-01

    Full Text Available High capital cost is a significant hindrance to the promotion of prefabrication. In order to optimize cost management and reduce capital cost, this study aims to explore the latent factors and factor analysis evaluation model. Semi-structured interviews were conducted to explore potential variables and then questionnaire survey was employed to collect professionals’ views on their effects. After data collection, exploratory factor analysis was adopted to explore the latent factors. Seven latent factors were identified, including “Management Index”, “Construction Dissipation Index”, “Productivity Index”, “Design Efficiency Index”, “Transport Dissipation Index”, “Material increment Index” and “Depreciation amortization Index”. With these latent factors, a factor analysis evaluation model (FAEM, divided into factor analysis model (FAM and comprehensive evaluation model (CEM, was established. The FAM was used to explore the effect of observed variables on the high capital cost of prefabrication, while the CEM was used to evaluate comprehensive cost management level on prefabrication projects. Case studies were conducted to verify the models. The results revealed that collaborative management had a positive effect on capital cost of prefabrication. Material increment costs and labor costs had significant impacts on production cost. This study demonstrated the potential of on-site management and standardization design to reduce capital cost. Hence, collaborative management is necessary for cost management of prefabrication. Innovation and detailed design were needed to improve cost performance. The new form of precast component factories can be explored to reduce transportation cost. Meanwhile, targeted strategies can be adopted for different prefabrication projects. The findings optimized the capital cost and improved the cost performance through providing an evaluation and optimization model, which helps managers to

  16. The Aspergillus niger MADS-box transcription factor RlmA is required for cell wall reinforcement in response to cell wall stress.

    NARCIS (Netherlands)

    Damveld, R.A.; Arentshorst, M.; Franken, A.; Vankuyk, P.A.; Klis, F.M.; van den Hondel, C.A.; Ram, A.F.

    2005-01-01

    In Aspergillus niger, the genes coding for glutamine:fructose-6-phosphate amidotransferase (gfaA) and ¿-1,3-glucan synthase (agsA) are induced in response to cell wall stress. In silico analysis of the promoter region of the two genes revealed the presence of putative DNA binding sites for

  17. Prefabricated fibula free flap with dental implants for mandibular reconstruction.

    Science.gov (United States)

    Pauchet, D; Pigot, J-L; Chabolle, F; Bach, C-A

    2018-03-02

    Free fibula transplant is routinely used for mandibular reconstruction in head and neck cancer. Dental rehabilitation, the objective of mandibular reconstruction, requires the use of dental implants as supports for fixed or removable dentures. Positioning of fibular bone grafts and implants determines implant osseointegration and the possibilities of dental rehabilitation. Prefabrication of a fibula free flap with dental implants prior to harvesting as a free flap can promote implant osseointegration. The position of the implants must then be precisely planned. Virtual surgery and computer-assisted design and prefabrication techniques are used to plan the reconstruction and then reproduce this planning by means of tailored fibula and mandible cutting guides, thereby ensuring correct positioning of fibular bone fragments and implants. The prefabricated fibula free flap technique requires two surgical procedures (prefabrication and flap transfer) and precise preoperative planning. Prefabricated fibula free flap with dental implants, by improving the quality of osseointegration of the implants before flap transfer, extends the possibilities of prosthetic rehabilitation in complex secondary mandibular reconstructions. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  18. Hygrothermal Modeling in the Application of Fiber-Reinforced Polymers for Structural Upgrade of Unreinforced Masonry Walls

    National Research Council Canada - National Science Library

    Feickert, Carl A; Lin, Mark W; Trovillion, Jonathan C; Abatan, Ayo O; Berman, Justin B

    2003-01-01

    .... In some instances, these aging structures fail to meet prevailing seismic engineering codes. In the United States alone, 30 percent of the Army's structures use unreinforced masonry (URM) walls...

  19. Safety concerns related to modular/prefabricated building construction.

    Science.gov (United States)

    Fard, Maryam Mirhadi; Terouhid, Seyyed Amin; Kibert, Charles J; Hakim, Hamed

    2017-03-01

    The US construction industry annually experiences a relatively high rate of fatalities and injuries; therefore, improving safety practices should be considered a top priority for this industry. Modular/prefabricated building construction is a construction strategy that involves manufacturing of the whole building or some of its components off-site. This research focuses on the safety performance of the modular/prefabricated building construction sector during both manufacturing and on-site processes. This safety evaluation can serve as the starting point for improving the safety performance of this sector. Research was conducted based on Occupational Safety and Health Administration investigated accidents. The study found 125 accidents related to modular/prefabricated building construction. The details of each accident were closely examined to identify the types of injury and underlying causes. Out of 125 accidents, there were 48 fatalities (38.4%), 63 hospitalized injuries (50.4%), and 14 non-hospitalized injuries (11.2%). It was found that, the most common type of injury in modular/prefabricated construction was 'fracture', and the most common cause of accidents was 'fall'. The most frequent cause of cause (underlying and root cause) was 'unstable structure'. In this research, the accidents were also examined in terms of corresponding location, occupation, equipment as well as activities during which the accidents occurred. For improving safety records of the modular/prefabricated construction sector, this study recommends that future research be conducted on stabilizing structures during their lifting, storing, and permanent installation, securing fall protection systems during on-site assembly of components while working from heights, and developing training programmes and standards focused on modular/prefabricated construction.

  20. Desferrioxamine: a practical method for improving neovascularization of prefabricated flaps.

    Science.gov (United States)

    Li, Bin; Li, Hua; Jin, Rui; Cheng, Chen; Wang, Jing; Zhu, Hainan; Zan, Tao; Li, Qingfeng; Hao, Lijun

    2015-02-01

    Prefabricated flaps are an ideal alternative to repair massive and complex tissue defects. Nevertheless, the risk of necrosis due to unpredictable blood supplies is a major obstacle to the application of prefabricated flaps. The survival of a prefabricated flap depends on the neovascularization between the vascular carrier and the donor tissue. Here, we proposed that the iron chelator, desferrioxamine (DFX), owned therapeutic effects that promoted the neovascularization of prefabricated flaps. An abdominal prefabricated flap model was created in rats via a 2-stage operation. The rats were allocated into 4 groups as follows: 2 groups of rats received DFX treatments during the first or the second stage of the operation, respectively; 1 group of rats received a delay procedure 1 week before the second operation; and the final group was used as a blank control. Flap survival rates and capillary densities were evaluated between groups. The influence of DFX on the dermal fibroblasts was also studied in vitro. Desferrioxamine treatment during the first stage of the operation greatly increased flap survival rate compared to the blank control. The results were similar to those produced by the delay treatment. The vessel count results were consistent with the flap survival rate findings. In vitro, DFX treatment up-regulated the expression levels of several angiogenic factors in the dermal fibroblasts. Nevertheless, DFX treatment during the second stage of the operation was therapeutically detrimental. The application of DFX around the time of vascular carrier implantation greatly promoted neovascularization of prefabricated flaps, but was therapeutically detrimental after the flaps had been elevated.

  1. Assesment risk of fracture in thin-walled fiber reinforced and regular High Performance Concretes sandwich elements

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hulin, Thomas; Schmidt, Jacob Wittrup

    2013-01-01

    load. Due to structural restraints, autogenous shrinkage may lead to high self-induced stresses. Therefore autogenous shrinkage plays important role in design of HPCSE. The present paper assesses risk of fracture due to autogenous shrinkage-induced stresses in three fiber reinforced and regular High....... Finally the paper describes the modeling work with HPCSE predicting structural cracking provoked by autogenous shrinkage. It was observed that risk of cracking due to autogenous shrinkage rapidly rises after 3 days in case of regular HPC and after 7 days in case of fiber reinforced HPC.......High Performance Concrete Sandwich Elements (HPCSE) are an interesting option for future low or plus energy building construction. Recent research and development work, however, indicate that such elements are prone to structural cracking due to the combined effect of shrinkage and high temperature...

  2. Stiffness of reinforced concrete walls resisting in-place shear -- Tier 2: Aging and durability of concrete used in nuclear power plants. Final report

    International Nuclear Information System (INIS)

    Monteiro, P.J.M.; Moehle, J.P.

    1995-12-01

    Reinforced concrete walls are commonly used in power-plant construction to resist earthquake effects. Determination of wall stiffness is of particular importance for establishing design forces on attached equipment. Available experimental data indicate differences between the measured and calculated stiffness of walls in cases where concrete mechanical properties are well defined. Additional data indicate that in-situ concrete mechanical properties may differ significantly from those specified in design. The work summarized in this report was undertaken to investigate the mechanical properties of concrete considering aging and deterioration. Existing data on mechanical properties of concrete are evaluated, and new tests are carried out on concrete cylinders batched for nuclear power plants and stored under controlled conditions for up to twenty years. It is concluded that concretes batched for nuclear power plants commonly have 28-day strength that exceeds the design value by at least 1000 psi. Under curing conditions representative of those in the interior of thick concrete elements, strength gain with time can be estimated conservatively using the expression proposed by ACI Committee 209, with strengths at 25 years being approximately 1.3 times the 28-day strength. Young's modulus can be estimated using the expression given by ACI Committee 318. Variabilities in mechanical properties are identified. A review of concrete durability identified the main causes and results of concrete deterioration that are relevant for the class of concretes and structures commonly used in nuclear power plants. Prospects for identifying the occurrence and predicting the extent of deterioration are discussed

  3. Heat transfer unit and method for prefabricated vessel

    Science.gov (United States)

    Tamburello, David A.; Kesterson, Matthew R; Hardy, Bruce J.

    2017-11-07

    Vessel assemblies, heat transfer units for prefabricated vessels, and methods for heat transfer prefabricated vessel are provided. A heat transfer unit includes a central rod, and a plurality of peripheral rods surrounding the central rod and connected to the central rod. The plurality of peripheral rods are movable between a first collapsed position and a second bowed position, wherein in the second bowed position a midpoint of each of the plurality of peripheral rods is spaced from the central rod relative to in the first position. The heat transfer unit further includes a heat transfer element connected to one of the plurality of peripheral rods.

  4. Buildings of prefabricated concrete elements after 40-50 years of use

    Directory of Open Access Journals (Sweden)

    Milićević Milan

    2002-01-01

    Full Text Available After the Second World War in demolished Europe, existed an acute need for the accommodation of people without a shelter, what affected the builders to accelerate construction of serial temporary residential buildings. Later, are developed various systems of prefabricated multistory buildings of reinforced concrete. Such a new system of construction has given these advantages: shorter time of construction, lower expenditure, higher quality of buildings, more flexibility. However, after some time, the first expectation of the above possibilities started diminishing, especially when are revealed problems in their use and maintenance. The experience achieved in the Nord areas of Europe can be, in a greater extent, applicated in the South, especially where are strong rains, wind and high temperatures. Here are interpreted experiences from Finland.

  5. NUMERICAL DERIVATIONS OF A MACROSCOPIC MODEL FOR REINFORCED CONCRETE WALLS CONSIDERING IN-PLANE AND OUT-OF-PLANE BEHAVIOR

    OpenAIRE

    LATCHAROTE; Panon KAI, Yoshiro

    2015-01-01

    A macroscopic model, macro plate model, was proposed to represent a wall member of RC walls. Both in-plane and out-of-plane behavior were considered for numerical derivations of macro plate model. For out-of-plane behavior, bending deformation was incorporated with shear deformation to consider out-of-plane deformation as same as in-plane behavior. The hysteretic behavior of macro plate model can be directly expressed by stress-strain relationships in any conventional hysteretic rules, which ...

  6. Study and Behaviour of Prefabricated Composite Cladding

    Science.gov (United States)

    Sai Avinash, P.; Thiagarajan, N.; Santhi, A. S.

    2017-07-01

    The incessant population rise entailed for an expeditious construction at competitive prices that steered the customary path to the light weight structural components. This lead to construction of structural components using ferrocement. The load bearing structural cladding, sizing 3200x900x100 mm, is chosen for the study, which, is analyzed using the software ABAQUS 6.14 in accordance with the IS:875-87 Part1, IS:875-87 Part2, ACI 549R-97, ACI 318R-08 and NZS:3101-06 Part1 standards. The Ferrocement claddings (FCs) are fabricated to a scaled dimension of 400x115x38 mm. The light weight-high strength phenomena are corroborated by incorporating Glass Fibre Reinforced Polymer Laminates (GFRPL) of thickness 6mm, engineered with the aid of hand layup (wet layup) technique wielding epoxy resin, followed by curing under room temperature. The epoxy resin is employed for fastening ferrocement cladding with the Glass fiber reinforced polymer laminate, with the contemporary methodology. The compressive load carrying capacity of the amalgamated assembly, both in presence and absence of Glass Fibre Reinforced polymer laminates (GFRPL) on either side of Ferrocement cladding, has been experimented.

  7. Microstructure and mechanical properties of nickel coated multi walled carbon nanotube reinforced stainless steel 316L matrix composites by laser sintering process

    Science.gov (United States)

    Mahanthesha, P.; Mohankumar, G. C.

    2018-04-01

    Electroless Ni coated Multi-walled Carbon nanotubes reinforced with Stainless Steel 316L matrix composite was developed by Direct Metal Laser Sintering process (DMLS). Homogeneous mixture of Stainless Steel 316L powder and carbon nanotubes in different vol. % was obtained by using double cone blender machine. Characterization of electroless Ni coated carbon nanotubes was done by using X-ray diffraction, FESEM and EDS. Test samples were fabricated at different laser scan speeds. Effect of process parameters and CNT vol. % content on solidification microstructure and mechanical properties of test samples was investigated by using Optical microscopy, FESEM, and Hounsfield tensometer. Experimental results reveal DMLS process parameters affect the density and microstructure of sintered parts. Dense parts with minimum porosity when processed at low laser scan speeds and low CNT vol. %. Tensile fractured surface of test specimens evidences the survival of carbon nanotubes under high temperature processing condition.

  8. Cracking of reinforced concrete short walls submitted to seismic solicitations - estimation of cracks openings: contribution to the improvement of knowledge, of experimental data to engineering applications

    International Nuclear Information System (INIS)

    Gallitre, E.

    2008-01-01

    Until now, the codified methods of crack opening estimation of reinforced concrete structures are based on formulations taking into account stresses of steels supposed to take again the whole stresses which have led to crack: these methods are not valid in the case of shear solicitations in short walls. With the detailed exploitation of the SAFE campaign, it has been possible to establish a global deformation formulated law. The problem being thus reported on the determination of the distortion, different methods have been tested, the more realistic being those in which non linear calculations involve. This work has ended by a return on the codified methods for nuclear power plants design revealing thus the points able to be improved or adapted. (O.M.)

  9. Numerical Analysis of Prefabricated Steel-Concrete Composite Floor in Typical Lipsk Building

    Directory of Open Access Journals (Sweden)

    Lacki Piotr

    2017-12-01

    Full Text Available The aim of the work was to perform numerical analysis of a steel-concrete composite floor located in a LIPSK type building. A numerical model of the analytically designed floor was performed. The floor was in a six-storey, retail and service building. The thickness of a prefabricated slab was 100 mm. The two-row, crisscrossed reinforcement of the slab was made from φ16 mm rods with a spacing of 150 x 200 mm. The span of the beams made of steel IPE 160 profiles was 6.00 m and they were spaced every 1.20 m. The steelconcrete composite was obtained using 80×16 Nelson fasteners. The numerical analysis was carried out using the ADINA System based on the Finite Element Method. The stresses and strains in the steel and concrete elements, the distribution of the forces in the reinforcement bars and cracking in concrete were evaluated. The FEM model was made from 3D-solid finite elements (IPE profile and concrete slab and truss elements (reinforcement bars. The adopted steel material model takes into consideration the plastic state, while the adopted concrete material model takes into account material cracks.

  10. Prefabricated elements and structures: Developments, tests and experiences

    DEFF Research Database (Denmark)

    Goltermann, Per

    2014-01-01

    Danish concrete structures are often built with prefabricated elements, joined together on the site and this provides a large challenge to constantly improve and optimize the elements, the joints and the models. DTU Byg has been active in the development, testing and modelling of new elements...

  11. Improving the Learning Process in the Latest Prefabricated School Buildings

    Science.gov (United States)

    Pons, Oriol; Oliva, Josep-Manuel; Maas, Sandra-Ruth

    2010-01-01

    Since 2000 hundreds of school centers have been constructed in Catalonia using industrialized technologies. These centers are modern, useful, educational edifices built using advantageous prefabricated technologies that improve the building process and reduce the environmental impact of the building. This article analyses whether these…

  12. Prefabricated Cervical Skin Flaps for Hemi-Facial Resurfacing: Elucidating the Natural History of Postoperative Edema Using Indocyanine Green.

    Science.gov (United States)

    Li, Ke; Min, Peiru; Sadigh, Parviz; Grassetti, Luca; Lazzeri, Davide; Torresetti, Matteo; Marsili, Riccardo; Feng, Shaoqing; Liu, Ningfei; Zhang, Yi Xin

    2018-02-01

    The increases in capillary wall permeability and capillary hydrostatic pressure are considered to be the causes for the acute swelling seen in flaps; however, disruption of the circulating flap lymphatics could be another contributory factor. In this study we monitor the development of flap edema in a series of 18 prefabricated flaps and aim to delineate the natural history of this phenomenon by use of lymphography. Postoperative swelling was monitored in a series of 18 pre-expanded prefabricated cervical skin flaps used for hemi-facial burns-scar resurfacing. Time to spontaneous resolution, presence or absence of venous congestion, and clinical outcome were recorded. In two cases, indocyanine-green (ICG) lymphography was used to monitor the dermal backflow pattern until swelling had completely resolved. Average moving velocity of ICG after injection as well as flap thickness was also recorded over the follow-up period. The average moving velocity of ICG in the flap lymphatics improved from 0.48 cm/min to 1.5 cm/min in the first 12 days after flap transfer. The dermal backflow pattern was stardust in the first 12 days, indicating moderate lymphedema, transforming to splash from week three, and a robust collecting lymphatic vessel occurring from the fifth month, indicating mild lymphedema and lymphatic channel recovery, respectively. Transient swelling was observed in all prefabricated flaps in our series. We postulate that this is mostly secondary to lymphatic disruption that subsides as lymphangiogenesis takes place. ICG lymphography is an inexpensive, safe, and easy-to-use imaging technology that could be used in the monitoring of postoperative lymphedema seen in prefabricated flaps.

  13. Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

    Science.gov (United States)

    Noh, M. S. Md; Kamarudin, A. F.; Mokhatar, S. N.; Jaudin, A. R.; Ahmad, Z.; Ibrahim, A.; Muhamad, A. A.

    2018-04-01

    Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

  14. Axial Collapse Characteristics of Aluminum/Carbon Fiber Reinforced Plastic Composite Thin-Walled Members with Different Section Shapes

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Woo Chae; Kim, Ji Hoon; Yang, In Young [Chosun University, Gwangju (Korea, Republic of); Lee, Kil Sung [Humancomposites CO. Ltd, Gunsan (Korea, Republic of); Cha, Cheon Seok [Dongkang College, Gwangju (Korea, Republic of); Ra, Seung Woo [SEOUL METAL CO. Ltd, Seoul (Korea, Republic of)

    2014-09-15

    In the present study, we aimed to obtain design data that can be used for the side members of lightweight cars by experimentally examining the types of effects that the changes in the section shape and outermost layer of an aluminum (Al)/carbon fiber reinforced plastic (CFRP) composite structural member have on its collapse characteristics. We have drawn the following conclusions based on the test results: The circular Al/CFRP composite impact-absorbing member in which the outermost layer angle was laminated at 0° was observed to be 52.9 and 49.93 higher than that of the square and hat-shaped members, respectively. In addition, the energy absorption characteristic of the circular Al/CFRP composite impact-absorbing member in which the outermost layer angle was laminated at 90° was observed to be 50.49 and 49.2 higher than that of the square and hat-shaped members, respectively.

  15. Experimental and numerical study of steel pipe with part-wall defect reinforced with fibre glass sleeve

    International Nuclear Information System (INIS)

    Mazurkiewicz, Lukasz; Tomaszewski, Michal; Malachowski, Jerzy; Sybilski, Kamil; Chebakov, Mikhail; Witek, Maciej; Yukhymets, Peter; Dmitrienko, Roman

    2017-01-01

    The paper presents numerical and experimental burst pressure evaluation of the gas seamless hot-rolled steel pipe. The main goal was to estimate mechanical toughness of pipe wrapped with composite sleeve and verify selected sleeve thickness. The authors used a nonlinear explicit FE code with constitutive models which allows for steel and composite structure failure modelling. Thanks to the achieved numerical and analytical results it was possible to perform the comparison with data received from a capacity test and good correlation between the results were obtained. Additionally, the conducted analyses revealed that local reduction of pipe wall thickness from 6 mm to 2.4 mm due to corrosion defect can reduce high pressure resistance by about 40%. Finally, pipe repaired by a fibre glass sleeve with epoxy resin with 6 mm thickness turned out more resistant than an original steel pipe considering burst pressure. - Highlights: • Numerical and experimental burst pressure evaluation of steel pipe was performed. • Seamless hot-rolled steel pipe with and without corrosion defect were considered. • Local reduction of pipe wall thickness from 6 to 2.4 mm reduces resistance by 40%. • Pipe repaired by a 6 mm fibre glass sleeve was more resistant than an original pipe.

  16. Transporting fibres as reinforcement in self-compacting concrete

    NARCIS (Netherlands)

    Grünewald, S.; Walraven, J.C.

    2009-01-01

    The development of self-compacting concrete (SCC) was an important step towards efficiency at building sites, rationally producing prefabricated concrete elements, better working conditions and improved quality and appearance of concrete structures. By adding fibres to SCC bar reinforcement can be

  17. An analytical model for shape memory alloy fiber-reinforced composite thin-walled beam undergoing large deflection

    Directory of Open Access Journals (Sweden)

    Yongsheng Ren

    2015-03-01

    Full Text Available The structural model of the thin-walled laminated beams with integral shape memory alloy active fibers and accounting for geometrically nonlinear is presented in this article. The structural modeling is split into two parts: a two-dimensional analysis over the cross section and a geometrically nonlinear analysis of a beam along the beam span. The variational asymptotic method is used to formulate the force–deformation relationship equations taking into account the presence of active shape memory alloy fibers distributed along the cross section of the beam. The geometrically nonlinear governing equations are derived using variational principle and based on the von Kármán-type nonlinear strain–displacement relations. The equations are then solved using Galerkin’s method and an incremental Newton–Raphson method. The validation for the proposed model has been carried out by comparison of the present results with those available in the literature. The results show that significant extension, bending, and twisting coupled nonlinear deflections occur during the phase transformation due to shape memory alloy actuation. The effects of the volume fraction of the shape memory alloy fiber and ply angle are also addressed.

  18. Investigation on Prefabricated Building System Skilled Component Installers

    OpenAIRE

    Nurul Rezuana Buyung; Md Azree Othuman Mydin; Abdul Naser Abdul Ghani

    2013-01-01

    In the face of an increasingly challenging era of globalization, skills and new equipments which includes prefabricated building components, known as Industrialized Building System (IBS) has been introduced towards achievement of sustainable construction. IBS is a construction system in which the components are manufactured in a factory, on or off site, positioned and assembled into complete structures with minimal additional site work. IBS requires high construction precisi...

  19. Attempt of application of prefabrication techniques to nuclear engineering

    International Nuclear Information System (INIS)

    Frangi, Roger

    1981-01-01

    Prefabrication can apply to nuclear civil engineering for the execution of complicated or tall shuttering or casing work, requiring shoring that one would wish to simplify or suppress. This technique saves on work hours and improves quality and safety. A few examples carried out on the Saint-Laurent-des-Eaux and Chinon power stations are given as well as that which will be undertaken on the Belleville power station [fr

  20. Consolidation by Prefabricated Vertical Drains with a Threshold Gradient

    OpenAIRE

    Xiao Guo; Kang-He Xie; Yue-Bao Deng

    2014-01-01

    This paper shows the development of an approximate analytical solution of radial consolidation by prefabricated vertical drains with a threshold gradient. To understand the effect of the threshold gradient on consolidation, a parametric analysis was performed using the present solution. The applicability of the present solution was demonstrated in two cases, wherein the comparisons with Hansbo’s results and observed data were conducted. It was found that (1) the flow with the threshold gradie...

  1. Improved monolithic reinforced concrete construction for nuclear power stations

    International Nuclear Information System (INIS)

    Guenther, P.; Fischer, K.

    1983-01-01

    Experience has shown that in applying monolithic reinforced concrete in nuclear power plant construction the following auxiliary means are useful: measuring sheets in assembling, welding gauges for reaching high tolerance accuracies of prefabricated reinforced concrete members, suitable lining materials, formwork anchorage and formwork release agents, concrete workability agents, mechanized procedures for finishing and assembling. These means were successfully tested in constructing the Greifswald nuclear power station

  2. Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

    International Nuclear Information System (INIS)

    Kausar, A.

    2016-01-01

    Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

  3. A Method of Assembling Wall or Floor Elements

    DEFF Research Database (Denmark)

    2002-01-01

    The invention relates to a method of constructing, at the site of use, a building wall (1) or a building floor (1) using a plurality of prefabricated concrete or lightweight concrete plate-shaped wall of floor elements (10), in particular cast elements, which have a front side and a rear side...

  4. Functionalized Multi walled Carbon Nano tubes-Reinforced Viny lester/Epoxy Blend Based Nano composites: Enhanced Mechanical, Thermal, and Electrical Properties

    International Nuclear Information System (INIS)

    Praharaj, A. P.; Behera, D.; Bastia, T. K.; Rout, A. K.

    2015-01-01

    This paper presents a study on the mechanical, thermal, and electrical characterization of a new class of low cost multiphase nano composites consisting of Vinyl ester resin/epoxy (VER/EP) blend (40:60 w/w) reinforced with amine functionalized multi walled carbon nano tubes (f-MWCNTs). Five different sets of VER/EP nano composites are fabricated with addition of 0, 1, 3, 5, and 7 wt.% of f-MWCNTs. A detailed investigation of mechanical properties like tensile strength, impact strength, Young’s modulus, and hardness, thermal properties like thermogravimetric analysis (TGA) and thermal conductivity, electrical properties like dielectric strength, dielectric constant, and electrical conductivity, and corrosive and swelling properties of the nano composites has been carried out. Here, we report significant improvement in all the above properties of the fabricated nano composites with nano filler (f-MWCNTs) addition compared to the virgin blend (0 wt. nano filler loading). The properties are best observed in case of 5 wt.% nano filler loading with gradual deterioration thereafter which may be due to the nucleating tendency of the nano filler particles. Thus the above nano composites could be a preferable candidate for a wide range of structural, thermal, electrical, and solvent based applications.

  5. Experimental study on the influence of the opening in brick-masonry wall to seismic performance of reinforced concrete frame structures

    Science.gov (United States)

    Maidiawati, Tanjung, Jafril; Medriosa, Hamdeni

    2017-10-01

    Reinforced concrete (RC) frame structures with brick-masonry infills are commonly used in developing countries and high-risk seismic area, such as Indonesia. Significant researches have been carried out for studying the seismic performance of RC frame structures with brick-masonry infills. Only few of them focused on effects of the opening in the brick-masonry infill to the seismic performance of the RC frame structures. The presence of opening in brick-masonry infill is often used for placing doors and windows as well, however, it may reduce the seismic performance of the RC frame structure. In the current study, they influence of the opening in brick-masonry infills to the seismic performance RC frame structure will experimentally evaluated. Five of 1/4-scaled single story and single bay RC frame specimens were prepared, i.e. an RC bare frame, a clay brick-masonry infilled RC frame and three of clay brick-masonry infilled RC frame with openings in the brick-masonry infills. The last three specimens were clay brick infilled RC frame with a center opening, clay brick infilled RC frame with two openings used for placing the windows and clay brick infilled RC frame with opening for placing the door. The specimens pushed over by applying the static monotonic lateral load to the upper beam of the RC frame structures. The incremental of the lateral load and the lateral displacement of RC frame's column was recorded during test. The crack propagation and the major cracks were also observed to identify the mechanism failure of specimens. As the results, the opening in the brick-masonry wall controls the failure mechanism, the lateral strength and the stiffness of the overall of infilled RC frame structure. The diagonal shear crack pattern was found on brick-masonry wall without opening, on other hand the different crack patterns were observed on brick-masonry wall with openings. Although the opening in the brick masonry infill reduced the lateral strength and stiffness of

  6. Study on reinforced concrete high-rise building using prefabricated beam-column joints. Part 3. ; Basic anchorage behaviors of longitudinal bars of beams. Hahsirater dot hari setsugobu PC ka koho (PG connection koho) wo mochiita RC koso tatemono no kaihatsu. 3. ; Hari shukin no kisoteki teichaku seijo

    Energy Technology Data Exchange (ETDEWEB)

    SEkine, M.; Yoshioka, K.; Eto, H. (Obayashi Corp., Tokyo (Japan))

    1991-08-10

    Pull-out tests were carried out to examine basic anchorage behaviors of through holes for beam re-bars by using a PG connection method, in which columns and beam-column joints with through holes for beam re-bars in the reinforced concrete framed construction are precast simultaneously. Specimens made by the PG connection method showed better anchorage behaviors than specimens made by the conventional anchorage method. In case of anchorage width of 80cm and concrete strength of about 350kgf/cm{sup 2}, it was recognized that large slipping of re-bars did not occur under allowable bond stress when the interval between re-bars was not less than 15cm and covering depth to the core of re-bars was not less than 8cm. Concerning a specimen which did not show splitting bond failure because of lateral compressive stress, bond stress of re-bars when large slipping occurred was 1.5 times or more in comparison with the allowable bond stress. Since this specimen held high slipping rigidity even after increase of slipping, its anchoring stress increased by 32-57% compared with a specimen without lateral compressive stress. 4 refs., 7 figs., 3 tabs.

  7. Cost Effectiveness of Precast Reinforced Concrete Roof Slabs

    Science.gov (United States)

    Parskiy, N. D.; Molodtsov, M. V.; Molodtsova, V. E.

    2017-11-01

    Engineers always seek to free interior space from intermediate supporting elements. Nowadays plants, being at the forefront of technology, produce a new generation of exclusive patented prefabricated reinforced concrete elements with a high load-bearing capacity, excellent heat resistance characteristics combined with the aesthetics and beauty. It is a system of Seagull Gabbiano prestressed roof slabs for the spans of 12m - 40m. The article shows the advantages of the Seagull slabs over conventional precast reinforced concrete and metal roof trusses. It also gives the analysis of the technical and economic indices of design and construction of a building with the Seagull slabs depending on the size of spans to cover. The use of structural systems with increased spans allows for the modern buildings and structures of prefabricated reinforced concrete with enhanced functionality and aesthetics alongside with a wide range of planning solutions.

  8. Lateral resistance of plybamboo wall-panels

    OpenAIRE

    Gonzalez Beltran, G.E.; Herwijnen, van, F.; Janssen, J.J.A.; Moonen, S.P.G.; Gutierrez, J.A.

    2003-01-01

    This paper deals with the experimental and theoretical behavior of plybamboo (kind of plywood made out of bamboo) wall-panels subjected to lateral load. The wall-panels are part of a house design method proposed in the author's PhD thesis for prefabricated social housing in developing countries. Sixteen fullscaled wallpanels with or without window and door openings were tested and their theoretical capacities estimated. Design wind and seismic loads were determined according to the Internatio...

  9. Application of Prefabricated Vertical Drain in Soil Improvement

    Directory of Open Access Journals (Sweden)

    Tedjakusuma B.

    2012-01-01

    Full Text Available Although the use of Prefabricated Vertical Drain (PVD in soil improvement is not new, this paper is interesting since it gives the full spectrum from preliminary design stage; trial embankment and pilot test to final soil improvement. The final installation of the PVD was based on the soil investigation report and the results of instrumentation monitoring. Finally, using back analysis, vertical and horizontal coefficients of consolidation and compression index can be determined, which can be applied to predict a more accurate prediction of settlement.

  10. Funciones de vulnerabilidad calculadas para edificaciones en muros de hormigón reforzado Calculated seismic vulnerability functions for building in walls of reinforced concrete

    Directory of Open Access Journals (Sweden)

    Esperanza Maldonado Rondón

    2010-04-01

    Full Text Available En este documento se presenta una metodología que valora el nivel de daño que pueden alcanzar las edificaciones correspondientes al sistema estructural de muros de hormigón reforzado. El modelo estima un índice de vulnerabilidad calculado en función de las características de la estructura que más influyen en su comportamiento sísmico, y lo relaciona con un índice de daño, que a su vez depende de la acción del movimiento sísmico. El modelo estima diferentes grados de vulnerabilidad, y por consiguiente, define distintos niveles de daño ante una misma acción. La relación de la vulnerabilidad con el daño se materializa mediante una forma continua con las funciones de vulnerabilidad. El modelo se construyó sobre una muestra de edificaciones reales e hipotéticas las cuales representan las características más relevantes de las edificaciones de este tipo en el medio colombiano.This document contains a methodology to assess the level of damage that buildings with reinforced concrete wall structural system may reach. The model estimates a vulnerability rate calculated in function of structure characteristics that most influent a seismic behaviour, and relates this value to a damage rate, which, in turn, depends on the action of seismic movements. The model estimates different levels of vulnerability and, consequently, defines different damages produced the same action. The vulnerability / damage ratio is materialized to vulnerability function in a continuous manner. The model was constructed on a sample of real and hypothetical buildings representing the most relevant characteristics of this type of buildings in Colombia.

  11. Investigation of Mechanical and Thermal Properties of Polymer Composites Reinforced by Multi-Walled Carbon Nanotube for Reduction of Residual Stresses

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Ghasemi

    2014-08-01

    Full Text Available The micromechanical models are used to investigate mechanical and thermal properties of a polymer matrix nanocomposite containing multi-walled carbon nanotubes (MWCNT in their effects to reduce residual stresses in nanocomposites. To do this, first nanotubes with different weights and volume fractions were dispersed in ML-506 epoxy resin. By using different micromechanical models, the effect additional nanotubes on elastic modulus and coefficient of thermal expansion (CTE of nanotubes/epoxy were studied as critical parameters. Comparing the model and available experimental results, the modified Halpin-Tsai model and the modified Schapery model were chosen to calculate the mechanical and thermal properties of the nanocomposites. Then, using the matrix reinforced with MWCNT and classical micromechanics models the elastic modulus and coefficients of thermal expansion of the nanocomposites were determined for a single orthotropic ply. The results showed that the rule of mixture (ROM and Hashin-Rosen model to determine the longitudinal and transverse elastic moduli and Van Fo Fy model to calculate the coefficient of thermal expansion were in good agreements with the experimental results of a single-layer nanocomposite. Finally, the classical laminated plate theory (CLPT was used to calculate the residual stresses of the CNT/carbon fiber/epoxy composites with different weights and volume fractions of MWCNT for angle-ply, cross-ply and quasi-isotropic laminated composite materials. The results showed that residual stresses were reduced using a maximum of 1% wt or 0.675% volume fraction of the MWCNT in polymer composites. Also, the highest reduction in residual stresses was observed in [02/902] cross-ply laminated composite materials.

  12. Accuracy of secondary maxillofacial reconstruction with prefabricated fibula grafts using 3D planning and guided reconstruction

    NARCIS (Netherlands)

    Schepers, Rutger H.; Kraeima, Joep; Vissink, Arjan; Lahoda, Lars U.; Roodenburg, Jan L. N.; Reintsema, Harry; Raghoebar, Gerry M.; Witjes, Max J.

    Background: We compared the pre-operative 3D-surgical plan with the surgical outcome of complex two-stage secondary reconstruction of maxillofacial defects using inserted implants in the prefabricated fibula graft. Methods: Eleven reconstructions of maxillofacial defects with prefabricated fibulas

  13. A Market Equilibrium Supply Chain Model for Supporting Self-Manufacturing or Outsourcing Decisions in Prefabricated Construction

    OpenAIRE

    Yanhu Han; Miroslaw J. Skibniewski; Lufan Wang

    2017-01-01

    Prefabricated construction is a sustainable alternative to traditional on-site construction methods. However, many challenges still exist in the prefabricated construction process. For example, self-manufacturing or outsourcing decisions are vital to the industrial structure and organization of the prefabricated construction industry, and the company’s production and operation decision-making. This paper considers a prefabricated construction supply chain, which is composed of one upstream co...

  14. The effects of local nitroglycerin on the surgical delay procedure in prefabricated flaps by vascular implant in rats.

    Science.gov (United States)

    Sá, Jairo Zacchê de; Aguiar, José Lamartine de Andrade; Cruz, Adriana Ferreira; Schuler, Alexandre Ricardo Pereira; Lima, José Ricardo Alves de; Marques, Olga Martins

    2012-12-01

    To evaluate the effect of local nitroglycerin on the viable area of a prefabricated flap for vascular implant in rats, and to investigate the surgical delay procedure. A femoral pedicle was implanted under the skin of the abdominal wall in forty Wistar rats. The animals were divided into four groups of ten: group 1 - without surgical delay procedure and local nitroglycerin; group 2 - with surgical delay procedure, but without local nitroglycerin; group 3 - without surgical delay procedure, but with local nitroglycerin; and group 4 - with simultaneous surgical delay procedure and local nitroglycerin. The percentages of the viable areas, in relation to the total flap, were calculated using AutoCAD R 14. The mean percentage value of the viable area was 8.9% in the group 1. 49.4% in the group 2; 8.4% in the group 3 and 1.1% in the group 4. There was significant difference between groups 1 and 2 (p=0.005), 1 and 4 (p=0.024), 2 and 3 (p=0.003), 2 and 4 (p=0.001). These results support the hypothesis that the closure of the arterial venous channels is responsible for the phenomenon of surgical delay procedure. Local nitroglycerin did not cause an increase in the prefabricated viable flap area by vascular implantation and decreased the viable flap area that underwent delay procedures.

  15. Prefabricated light-polymerizing plastic pattern for partial denture framework

    Directory of Open Access Journals (Sweden)

    Atsushi Takaichi

    2011-01-01

    Full Text Available Our aim is to report an application of a prefabricated light-polymerizing plastic pattern to construction of removable partial denture framework without the use of a refractory cast. A plastic pattern for the lingual bar was adapted on the master cast of a mandibular Kennedy class I partially edentulous patient. The pattern was polymerized in a light chamber. Cobalt-chromium wires were employed to minimize the potential distortion of the plastic framework. The framework was carefully removed from the master cast and invested with phosphate-bonded investment for the subsequent casting procedures. A retentive clasp was constructed using 19-gauge wrought wire and was welded to the framework by means of laser welding machine. An excellent fit of the framework in the patient′s mouth was observed in the try-in and the insertion of the denture. The result suggests that this method minimizes laboratory cost and time for partial denture construction.

  16. Marine Spongin: Naturally Prefabricated 3D Scaffold-Based Biomaterial

    Science.gov (United States)

    Jesionowski, Teofil; Norman, Małgorzata; Żółtowska-Aksamitowska, Sonia; Petrenko, Iaroslav; Ehrlich, Hermann

    2018-01-01

    The biosynthesis, chemistry, structural features and functionality of spongin as a halogenated scleroprotein of keratosan demosponges are still paradigms. This review has the principal goal of providing thorough and comprehensive coverage of spongin as a naturally prefabricated 3D biomaterial with multifaceted applications. The history of spongin’s discovery and use in the form of commercial sponges, including their marine farming strategies, have been analyzed and are discussed here. Physicochemical and material properties of spongin-based scaffolds are also presented. The review also focuses on prospects and trends in applications of spongin for technology, materials science and biomedicine. Special attention is paid to applications in tissue engineering, adsorption of dyes and extreme biomimetics. PMID:29522478

  17. Design and development of Building energy simulation Software for prefabricated cabin type of industrial building (PCES)

    Science.gov (United States)

    Zhang, Jun; Li, Ri Yi

    2018-06-01

    Building energy simulation is an important supporting tool for green building design and building energy consumption assessment, At present, Building energy simulation software can't meet the needs of energy consumption analysis and cabinet level micro environment control design of prefabricated building. thermal physical model of prefabricated building is proposed in this paper, based on the physical model, the energy consumption calculation software of prefabricated cabin building(PCES) is developed. we can achieve building parameter setting, energy consumption simulation and building thermal process and energy consumption analysis by PCES.

  18. Development of Flexible Link Slabs using Ductile Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi

    Civil engineering structures with large dimensions, such as multi-span bridges, overpasses and viaducts, are typically equipped with mechanical expansion joints. These joints allow the individual spans of the structure to undergo unrestrained deformations due to thermal expansions and load......-deformation response and crack development of representative sections of the reinforced composites, and iv) detailing, designing and testing of large scale prefabricated link slab elements. In addition, an application of ductile Engineered Cementitious Composite (ECC) in prefabricated floor panels is presented...... crack widths and crack spacing measurements are obtained, which can characterize the tensile behavior of ECC. In chapter 3 on interfacial bond, the bond slip behavior and crack development, between the reinforcement and surrounding cementitious matrix is investigated in a unique test setup with special...

  19. Research on Investment Risk Management of Chinese Prefabricated Construction Projects Based on a System Dynamics Model

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-09-01

    Full Text Available Prefabricated construction, a new direction for the future development of the Chinese construction industry, can maximize the requirements of “green”. As a new form of green building, prefabricated construction is of particular interest. On account of the immature development of the green building market in China, the investment risk for prefabricated construction is higher than for traditional architecture. Hence, it is especially important to improve its investment risk identification and management. This study adopts system dynamics and builds a risk identification feedback chart and risk flow chart, to comprehensively identify investment risks that projects in China may face and to process quantitative estimation of investment risk factors. Key factors influencing project investment risks are found, and corresponding measures are pointedly proposed. This paper may provide guidance and a reference for promoting the sound development of prefabricated construction in China.

  20. The prefabricated building risk decision research of DM technology on the basis of Rough Set

    Science.gov (United States)

    Guo, Z. L.; Zhang, W. B.; Ma, L. H.

    2017-08-01

    With the resources crises and more serious pollution, the green building has been strongly advocated by most countries and become a new building style in the construction field. Compared with traditional building, the prefabricated building has its own irreplaceable advantages but is influenced by many uncertainties. So far, a majority of scholars have been studying based on qualitative researches from all of the word. This paper profoundly expounds its significance about the prefabricated building. On the premise of the existing research methods, combined with rough set theory, this paper redefines the factors which affect the prefabricated building risk. Moreover, it quantifies risk factors and establish an expert knowledge base through assessing. And then reduced risk factors about the redundant attributes and attribute values, finally form the simplest decision rule. This simplest decision rule, which is based on the DM technology of rough set theory, provides prefabricated building with a controllable new decision-making method.

  1. LOGISTICS RISK RESEARCH OF PREFABRICATED HOUSE CONSTRUCTION ENGINEERING BASED ON CREDIBILITY METHOD

    Directory of Open Access Journals (Sweden)

    Xiaoping Bai

    2017-07-01

    Full Text Available In recent years, the prefabricated house industry has rapid development,.Because of fewer suppliers, higher demand transport scheme and complex quality test, the risks of construction engineering logistics links are relatively high. Studying how to effectively evaluate the risks of construction engineering logistics links is significant. According to the characteristics of the prefabricated house construction engineering, we analyse the construction engineering logistics risks and use the combined weights method to determine the weight of indexes which contains both subjective and objective factors, to improve the scientific value and the validity of the assessment. Based on credibility measure method, a new logistics risk evaluation model in prefabricated housing is established to estimate the risk during making prefabricated house construction engineering. The presented model can avoid the subjectivity of selecting the membership function and solve the problem of how to comprehensively assess the construction engineering logistics risk in a certain extent.

  2. Injection molding of micro pillars on vertical side walls using polyether-ether-ketone (PEEK)

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; Sørensen, Søren

    2016-01-01

    This paper investigates the replication of microstructures on a vertical wall by PEEK injection molding. A 4-cavity insert was used in the injection molding. Pre-fabricated nickel plates with ø 4 μm micro holes on the surface were glued on vertical walls in the cavities. 3 cavities were coated by...

  3. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat....... Codes for designing prefabricated reinforced components of aircrete structures have adopted these recently developed approaches.......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  4. Consolidation by Prefabricated Vertical Drains with a Threshold Gradient

    Directory of Open Access Journals (Sweden)

    Xiao Guo

    2014-01-01

    Full Text Available This paper shows the development of an approximate analytical solution of radial consolidation by prefabricated vertical drains with a threshold gradient. To understand the effect of the threshold gradient on consolidation, a parametric analysis was performed using the present solution. The applicability of the present solution was demonstrated in two cases, wherein the comparisons with Hansbo’s results and observed data were conducted. It was found that (1 the flow with the threshold gradient would not occur instantaneously throughout the whole unit cell. Rather, it gradually occurs from the vertical drain to the outside; (2 the moving boundary would never reach the outer radius of influence if R+1

  5. Contribution to the understanding of the behaviour of reinforced concrete shear walls under seismic loading: contribution of experiment and modeling to the design; Contribution a la comprehension du fonctionnement des voiles en beton arme sous sollicitation sismique: apport de l'experimentation et de la modelisation a la conception

    Energy Technology Data Exchange (ETDEWEB)

    Ile, N

    2000-12-01

    This thesis deals with aspects of seismic behaviour of reinforced concrete shear walls (RCSW). Its objective is to introduce a useful modelling approach for addressing the non-linear response of a large variety of RCSW and to identify several aspects in which this numerical approach could be implemented into design applications. Firstly, the characteristics of the behaviour of RCSW under seismic loading, some design principles and different modelling approaches are discussed. As an important lack of knowledge in several fields was identified, it was considered that three types of shear walls deserve more attention: slightly reinforced slender walls; U-shaped walls and heavily reinforced squat shear walls. A local modelling approach is adopted and the material constitutive models are described in details. Secondly, the behaviour of the two mock-up, CAMUS I and II, tested on the shaking-table during the CAMUS programme, which are slightly reinforced and designed according to the French code PS92 is simulated using a 2-D finite element model (FEM). For comparison purposes, the case of the CAMUS III mock-up, designed according to EC8, is considered. We are then dealing with the case of U-shaped walls under dynamic and cyclic loading. The results obtained from numerical simulations, based on a 3-D shell FEM, are compared with those obtained from tests carried out in the frame of the ICONS programme. Finally, the numerical model is applied to the case of heavily reinforced squat shear walls (similar to those used in the nuclear power plant buildings) subjected to shear loading. A 2-D FEM is considered in order to simulate the behaviour of three different walls, which were tested pseudo-dynamically during the SAFE programme. The results from both experimental and numerical studies are compared and discussed. The most important factors affecting the behaviour of RCSW are highlighted. Different examples of possible contributions to design are presented. (author)

  6. Contribution to the understanding of the behaviour of reinforced concrete shear walls under seismic loading: contribution of experiment and modeling to the design; Contribution a la comprehension du fonctionnement des voiles en beton arme sous sollicitation sismique: apport de l'experimentation et de la modelisation a la conception

    Energy Technology Data Exchange (ETDEWEB)

    Ile, N

    2000-12-01

    This thesis deals with aspects of seismic behaviour of reinforced concrete shear walls (RCSW). Its objective is to introduce a useful modelling approach for addressing the non-linear response of a large variety of RCSW and to identify several aspects in which this numerical approach could be implemented into design applications. Firstly, the characteristics of the behaviour of RCSW under seismic loading, some design principles and different modelling approaches are discussed. As an important lack of knowledge in several fields was identified, it was considered that three types of shear walls deserve more attention: slightly reinforced slender walls; U-shaped walls and heavily reinforced squat shear walls. A local modelling approach is adopted and the material constitutive models are described in details. Secondly, the behaviour of the two mock-up, CAMUS I and II, tested on the shaking-table during the CAMUS programme, which are slightly reinforced and designed according to the French code PS92 is simulated using a 2-D finite element model (FEM). For comparison purposes, the case of the CAMUS III mock-up, designed according to EC8, is considered. We are then dealing with the case of U-shaped walls under dynamic and cyclic loading. The results obtained from numerical simulations, based on a 3-D shell FEM, are compared with those obtained from tests carried out in the frame of the ICONS programme. Finally, the numerical model is applied to the case of heavily reinforced squat shear walls (similar to those used in the nuclear power plant buildings) subjected to shear loading. A 2-D FEM is considered in order to simulate the behaviour of three different walls, which were tested pseudo-dynamically during the SAFE programme. The results from both experimental and numerical studies are compared and discussed. The most important factors affecting the behaviour of RCSW are highlighted. Different examples of possible contributions to design are presented. (author)

  7. Investigation on Prefabricated Building System Skilled Component Installers

    Directory of Open Access Journals (Sweden)

    Nurul Rezuana Buyung

    2013-09-01

    Full Text Available In the face of an increasingly challenging era of globalization, skills and new equipments which includes prefabricated building components, known as Industrialized Building System (IBS has been introduced towards achievement of sustainable construction. IBS is a construction system in which the components are manufactured in a factory, on or off site, positioned and assembled into complete structures with minimal additional site work. IBS requires high construction precision and needs a higher skill level of workers. Compared to the conventional construction method, the skill level of IBS workers is more demanding. Although there are a lot benefits in implementing IBS, the construction industry still not rapidly implementing IBS. The IBS method still considered new and even though there are a lot of benefits it still faces barriers. In an IBS construction, the role of the contractor is shifted from a builder to an assembler on the site. Therefore, this requires the contractor to be prepared technologically with IBS knowledge and skills. It is generally perceived that the number of skilled IBS installers in Malaysia is still low even though the system has been implemented for a long time. This research is carried out to find out whether the existing number of IBS installer is sufficient. Primary data was collected by carrying out interviews with the contractors at the IBS construction site in Penang Island in order to get the contractor’s feedback regarding this issue. Meanwhile, the secondary data was collected from government agencies to get the number of existing IBS installer and the number of IBS projects done in government projects. The results from this study indicated that not all categories of skill workers are in shortage. However, the number of precast concrete installer is in a critical shortage.

  8. Application of Prefabricated Panels for the Energy Retrofit of Portuguese Residential Buildings Facades: A Case Study

    Directory of Open Access Journals (Sweden)

    Sousa J.

    2013-09-01

    Full Text Available This article aims to evaluate the potential application of prefabricated panels in energy retrofit of facades in the Portuguese building stock. The fundamentals of this study were part of Annex 50, which was an international ECBCS IEA project, with the purpose of developing an innovative concept of building renovation for the most representative buildings based on prefabricated systems. To analyze the potential application of energy retrofit using prefabricated panels, was important to know the reality of the existing building stock and its morphology. To know the reality of the building stock, an analysis was done based on the existing statistical data and to find the most representative residential buildings, target of the study, three criteria were defined: buildings built before 1990, with 2 to 6 floors and with renovation needs in the exterior envelope.

  9. Prefabrication of a vascularized nerve graft by vessel implantation: preliminary report of an experimental model.

    Science.gov (United States)

    Cavadas, P C; Vera-Sempere, F J

    1994-01-01

    Regeneration through vascularized nerve grafts (VNG) seems to be better than nonvascularized nerve grafts (NVNG), especially in hostile beds. We report on an experimental technique of prefabrication of VNG by direct vessel implantation. An arteriovenous fistula was created in the groin region with autologous vein grafts in the Wistar rat model, and implanted into the sciatic nerve. Five weeks later the sciatic VNG was elevated on the prefabricated pedicle. The flap was free-transferred orthotopically over a silicone sheet to impede plasmatic imbibition. Flap viability at 3 days was complete. India ink injection of the AV fistula resulted in capillary ink filling within the nerve and surrounding tissues. Histologic sections of the flap were examined, revealing its neovascularity. In an ongoing study, the regeneration through this prefabricated VNG is being compared to native VNG.

  10. Research Advances on Fabricated Shear Wall System

    Science.gov (United States)

    Liu, Xudong; Wang, Donghui; Wang, Sheng; Zhai, Yu

    2018-03-01

    With the rapid development of the construction industry, building energy consumption has been increasing, has become a problem that can not be ignored. It is imperative to develop energy-saving buildings. A new type of prefabricated shear wall is assembled and partially assembled by prefabricated parts, and some concrete is spliced together. The new structure has good integrity, seismic resistance and excellent energy saving and environmental protection performance. It reduces building energy consumption to a great extent. Therefore, the design method, manufacturing process, site assembly process and key technical problems of the system are discussed. For the construction industry gradually entered the energy conservation, environmental protection, safety and durability of sustainable development laid the foundation.

  11. Practical and safe implementation of disposal with prefabricated EBS modules

    International Nuclear Information System (INIS)

    Kawamura, Hideki; McKinley, Ian G.; Neall, Fiona B.

    2008-01-01

    The use of prefabricated EBS modules ('PEMs') to minimise the problems involved with handling compacted bentonite and ensuring that it is emplaced to established quality levels has been investigated in various national programmes for disposal of both HLW and SF. To date, however, this has tended to be decoupled from studies of related operational aspects such as assessing / minimising the consequences of use of concrete for support structures, ensuring ease of tele-operated reversal of waste packages during emplacement (e.g. in the event of operational disturbances) / retrieval at a later time, logistical optimisation (especially for programmes with large waste inventories) and cost minimisation. It is clear that specific aspects of operational safety and practicality can be considerably enhanced if designs are modified with a focus on them. It is trickier to provide optimised solutions, which simultaneously address all these critical points. Nevertheless, with a bit of lateral thinking, it appears possible to devise options that may not only ease the operational phase, but may also actually improve post-closure safety case robustness - although improved, more realistic performance assessment codes and databases will be needed to demonstrate this rigorously. To illustrate this approach, an example will be presented based of disposal of vitrified HLW in a fractured hard rock; the general principles involved are, however, also applicable to other higher activity wastes and other host rocks. Key aspects of the design are: Optimisation of PEM design for both short-term and long-term performance; Development of a rail emplacement system which eases remote handled emplacement / recovery; Large diameter, lined emplacement tunnels to ensure operational robustness; Use of multi-package overpacks (e.g. 6 HLW containers in each PEM) and short tunnels to ease emplacement logistics; and Backfilling with a non-swelling sacrificial pH buffer (eases handling and improves

  12. Enhanced ductility of Mg–3Al–1Zn alloy reinforced with short length multi-walled carbon nanotubes using a powder metallurgy method

    Directory of Open Access Journals (Sweden)

    Muhammad Rashad

    2015-08-01

    Full Text Available Mg–3Al–1Zn–CNTs composites, with different weight fractions (0.25–1.0 wt% of carbon nanotubes (CNTs were successfully fabricated via a powder metallurgy method. The processing parameters were adopted in such a way to have uniform dispersion of short length CNTs without any damage, as well as refined and dissolved β phases structures throughout the composite matrix. The composite exhibited impressive increase in microhardness (about +23% and tensile failure strain value (about +98% without significant compromise in tensile strength, compared to the un-reinforced Mg–3Al–1Zn alloy. The synthesized composites can be used in automotive and aerospace industries due to their low density and high specific strength.

  13. A new method for fabrication of thin plates and thin-walled cylinder made of fiber reinforced metal (FRM) and its application for the rotating drum of the nuclear fuel centrifugal separator

    International Nuclear Information System (INIS)

    Okamura, Tatsuya

    1978-01-01

    The composite materials using resins as the base materials show the defect that the characteristics deteriorate rapidly at elevated temperature. Therefore the FRMs using relatively ductile metals as the base materials combined with reinforcing fibers have been considered. The result of study on the combination of base materials and fibers and the manufacturing method is rarely reported in Japan. In FRMs, direct contact of fibers mutually must be avoided, especially making nodes lowers the strength extremely. The fibers must be long monofilaments of 0.1 to 0.2 mm diameter. High precision wire winding machines are required for making uniform FRMs. For the diffusion joining of preformed materials, in which fibers are put in order on metallic foils, pressure and heat are applied. The author succeeded to develop the technique for making thin-walled cylinders of FRMs, including the method of winding brittle filaments and the method of pressurizing and heating based on the difference of thermal expansion of dies. The mechanical properties of thin plates and thin-walled cylinders made of monofilaments of B, SiC and SUS and aluminum alloy foils were obtained, and rotation test of the cylinders was carried out. It was clarified that the FRMs of B-Al and SiC-Al groups are very excellent materials, and most suitable for the rotary drums of super-high speed centrifuges. (Kako, I.)

  14. An alternative method for facial resurfacing: supraclavicular skin prefabrication by perforator fascia flap.

    Science.gov (United States)

    Hocaoğlu, Emre

    2014-01-01

    Prefabrication of supraclavicular skin provides a useful source for flaps congruent with the face skin. Among various vascular sources that have been used for this purpose, anterolateral thigh fascia seems to represent a greater value because of having a long and strong vascular pedicle and negligible donor-site morbidity. In this regard, we present a technical report on using the lateral circumflex femoral artery perforator flap harvest technique in preparing an anterolateral thigh fascia flap for the prefabrication of the supraclavicular skin. The technique proved successful in resurfacing the facial skin of a young female patient with a giant congenital melanocytic hairy nevus on the left side of her face.

  15. Assessment of pre-fabricated bathrooms from the 1990s

    DEFF Research Database (Denmark)

    Morelli, Martin; Brandt, Erik

    2015-01-01

    -weight assembly kit with fibre reinforced concrete bottoms - Light-weight assembly kit of fibre reinforced concrete elements The use of an inspection scheme implied that a consistent visual assessment of the bathrooms included constructions, installations and measurable conditions, e.g. moisture content and crack...... sizes, was obtained. Each parameter in the inspection scheme was judged on a 5 step ranking scale of conditions and interrelated degree of consequences. The investigation of the 9 bathrooms indicated a generally high quality of the bathrooms. Many of the registered failures may be eliminated...... with increased maintenance. Specifically, mould growth on resilient silicone sealant was a problem in wet zones. More critically was the registered mould growth in the ceiling, where the mechanical ventilation was low. Both issues could to some degree be prevented by more focus on user habits and maintenance...

  16. Wrinkles in reinforced membranes

    Science.gov (United States)

    Takei, Atsushi; Brau, Fabian; Roman, Benoît; Bico, José.

    2012-02-01

    We study, through model experiments, the buckling under tension of an elastic membrane reinforced with a more rigid strip or a fiber. In these systems, the compression of the rigid layer is induced through Poisson contraction as the membrane is stretched perpendicularly to the strip. Although strips always lead to out-of-plane wrinkles, we observe a transition from out-of-plane to in plane wrinkles beyond a critical strain in the case of fibers embedded into the elastic membranes. The same transition is also found when the membrane is reinforced with a wall of the same material depending on the aspect ratio of the wall. We describe through scaling laws the evolution of the morphology of the wrinkles and the different transitions as a function of material properties and stretching strain.

  17. Reinforced soil structures. Volume I, Design and construction guidelines

    Science.gov (United States)

    1990-11-01

    This report presents comprehensive guidelines for evaluating and using soil reinforcement techniques in the construction of retaining walls, embankment slopes, and natural or cut slopes. A variety of available systems for reinforced soil including in...

  18. Homogenized rigid body and spring-mass (HRBSM) model for the pushover analysis of out-of-plane loaded unreinforced and FRP reinforced walls

    Science.gov (United States)

    Bertolesi, Elisa; Milani, Gabriele

    2017-07-01

    The present paper is devoted to the discussion of a series of unreinforced and FRP retrofitted panels analyzed adopting the Rigid Body and Spring-Mass (HRBSM) model developed by the authors. To this scope, a total of four out of plane loaded masonry walls tested up to failure are considered. At a structural level, the non-linear analyses are conducted replacing the homogenized orthotropic continuum with a rigid element and non-linear spring assemblage by means of which out of plane mechanisms are allowed. FRP retrofitting is modeled adopting two noded truss elements whose mechanical properties are selected in order to describe possible debonding phenomenon or tensile rupture of the strengthening. The outcome provided numerically are compared to the experimental results showing a satisfactory agreement in terms of global pressure-deflection curves and failure mechanisms.

  19. Carbon Reduction Measures-Based LCA of Prefabricated Temporary Housing with Renewable Energy Systems

    Directory of Open Access Journals (Sweden)

    Ling Dong

    2018-03-01

    Full Text Available Temporary housing plays an important role in providing secure, hygienic, private, and comfortable shelter in the aftermath of disaster (such as flood, fire, earthquake, etc.. Additionally, temporary housing can also be used as a sustainable form of on-site residences for construction workers. While most of the building components used in temporary housing can be manufactured in a plant, prefabrication technology improves the production efficiency of temporary housing; furthermore, integrated renewable energy systems, for example, solar photovoltaic (PV system, offer benefits for temporary housing operations. In order to assess the environmental impacts of prefabricated temporary housing equipped with renewable energy systems, this study first divides the life cycle of temporary housing into six stages, and then establishes a life cycle assessment (LCA model for each stage. Furthermore, with the aim of reducing the environmental impacts, life cycle carbon reduction measures are proposed for each stage of temporary housing. The proposed methodology is demonstrated using a case study in China. Based on the proposed carbon reduction measures, the LCA of a prefabricated temporary housing case study building equipped with renewable energy systems indicates a carbon emissions intensity of 35.7 kg/m2·per year, as well as a reduction in material embodied emissions of 18%, assembly emissions of 17.5%, and operational emissions of 91.5%. This research proposes a carbon reduction-driven LCA of temporary housing and contributes to promoting sustainable development of prefabricated temporary housing equipped with renewable energy systems.

  20. Prefabricated neck expanded skin flap with the superficial temporal vessels for facial resurfacing.

    Science.gov (United States)

    Lazzeri, Davide; Su, Weijie; Qian, Yunliang; Messmer, Caroline; Agostini, Tommaso; Spinelli, Giuseppe; Marcus, Jeffrey R; Levin, L Scott; Zenn, Micheal R; Zhang, Yi Xin

    2013-05-01

    The achievement of a normal-appearing face after surgical resurfacing remains an elusive goal. This is due in part to insufficient color matching, restoration of contours, and the persistence of visible scars. Flap prefabrication is a staged procedure that provides an independent axial blood supply to local expanded tissues. We describe a new reconstructive alternative with superior reconstructive surgical options for facial resurfacing that better matches damaged or discarded facial tissues. A superficial temporal fascial flap was harvested as the vascular supply of the prefabricated neck flap and located in a subcutaneous neck pocket over a tissue expander. After a 5-month period for expansion and maturation, the prefabricated skin flap was raised, islanded, and rotated to resurface the facial defect. Four patients with hemifacial postburn contracture and two patients affected by hemifacial vascular malformations aged 17 to 42 years (mean 29 years) were successfully treated with no major complication after a mean period of 15 months. Prefabricated neck-expanded skin flap demonstrated an excellent color and texture match with facial skin that surrounded the repair sites, and optimal aesthetic results were obtained. Importantly, facial expression was completely maintained due to thinness and pliability of the rotated skin. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  1. Optimization of concrete for prefabrication and quantification of its environmental impact

    NARCIS (Netherlands)

    Onghena, S.; Grunewald, S.; Schutter, G

    2016-01-01

    The development of strength is an important criterion for the production of
    prefabricated concrete elements. With seasonal changes of temperature that affect the development of concrete strength, daily cycles of often 18 hours or shorter have to bemaintained. The use of Ordinary Portland Cement

  2. Quantifying the waste reduction potential of using prefabrication in building construction in Hong Kong.

    Science.gov (United States)

    Jaillon, L; Poon, C S; Chiang, Y H

    2009-01-01

    As Hong Kong is a compact city with limited available land and high land prices, the construction of high-rise buildings is prevalent. The construction industry produces a significant amount of building waste. In 2005, about 21.5 million tonnes of construction waste were generated, of which 11% was disposed of in landfills and 89% in public filling areas. At the present rate, Hong Kong will run out of both public filling areas and landfill space within the next decade. The government is taking action to tackle the problem, such as by introducing a construction waste landfill charge, and promoting prefabrication to reduce on-site waste generation. This paper reports an ongoing study on the use of prefabrication in buildings and its impact on waste reduction in Hong Kong. A questionnaire survey was administered to experienced professionals, and case studies of recently completed building projects were conducted. The results revealed that construction waste reduction is one of the major benefits when using prefabrication compared with conventional construction. The average wastage reduction level was about 52%. This implies that a wider use of prefabrication could considerably reduce construction waste generation in Hong Kong and alleviate the burdens associated with its management.

  3. Evaluation of torque loss value of MAD/MAM zirconia abutments with prefabricated titanium abutments

    Directory of Open Access Journals (Sweden)

    Marzieh Alikhasi

    2013-04-01

    Full Text Available Background and Aims: In response to esthetic demand of patients, ceramic abutments have been developed. Despite esthetic of zirconia abutments, machining accuracy of these abutments has always been a question. Any misfit in the abutment-implant interface connection can lead to detorque and screw loosening. The aim of this study was to compare torque loss value of manually aided design/manually aided manufacture (MAD/MAM zirconia abutments with prefabricated titanium abutments. Materials and Methods: Seven titanium abutments (Branemark RP, Easy abutment and seven copy milled abutments which were duplicated from the prefabricated Zirkonzhan (ZirkonZahn, Sand in Taufers, Italy were prepared. After sintering process of zirconia abutment, all abutments were fastened with a torque screw under 35 Ncm. Detorque measurements were performed per group pushing the reverse button of the Torque controller soon after screw tightening with values registered. The mean torque loss were calculated and compared using Student's t test. Results: The mean of torque loss was 12.71 Ncm with standard deviation of 1.70 for prefabricated titanium abutments and 15.50 Ncm with standard deviation of 4.67 for MAD-MAM abutments. The difference between the two groups was not statistically significant (P=0.23. Conclusion: Within the limitation of this study, MAD-MAM ceramic abutments could maintain the applied torque comparing to the prefabricated abutments.

  4. Single-step reinforced microextraction of polycyclic aromatic hydrocarbons from soil samples using an inside needle capillary adsorption trap with electropolymerized aniline/multi-walled carbon nanotube sorbent.

    Science.gov (United States)

    Ghiasvand, Ali Reza; Yazdankhah, Fatemeh

    2017-03-03

    A polyaniline/multi-wall carbon nanotubes (PANI/MWCNT) composite was electrodeposited on the interior surface of a platinized stainless steel capillary needle and used to prepare an inside needle capillary adsorption trap (INCAT) device. The platinization expanded the interior adsorbing surface of the needle and made it more porous and cohesive for nanocomposite film. The nanocomposite was characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The fabricated INCAT was fixed into a cooling capsule to fabricate a cooling-assisted INCAT (CA-INCAT) system. The CA-INCAT device was used to extract polycyclic aromatic hydrocarbons (PAHs) from solid samples followed by gas chromatography-flame ionization detection (GC-FID) determination. To obtain the best extraction efficiency, the important experimental variables were studied and optimized. Under the optimal conditions, the limits of detection (LODs) for the studied PAHs were in the range of 0.002-0.02ngg -1 . Linear dynamic ranges (LDRs) for the calibration curves were found to be 0.1-30,000ngg -1 . Relative standard deviations (RSDs%) for six replicated analysis of 1ngg -1 PAHs were obtained 7.7-11%. The CA-INCAT-GC-FID method was successfully applied for the extraction and determination of PAHs in contaminated soil samples. The results were in agreement with those obtained by a validated ultrasound-assisted solvent extraction (UA-SE) method. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. LABORATORY EVALUATION ON PERFORMANCE OF GLASS FIBER REINFORCED PLASTIC MORTAR PIPE CULVERTS

    OpenAIRE

    Huawang Shi; Lianyu Wei

    2018-01-01

    This paper investigated the performance and behaviour of glass fiber reinforced plastic mortar (FRPM) pipes under different loading conditions. FRPM pipes with inner diameter of 1500 mm were prefabricated in factory. Mechanics performance testing (ring and axial compressive strength and elastic modulus), stiffness and fatigue test were carried out in laboratory. Ring stiffness test provided pipe stiffness (PS) which is a function of geometry and material type of pipe through parallel plate lo...

  6. Prefabricated Vertical Drain (PVD) and Deep Cement Mixing (DCM)/Stiffened DCM (SDCM) techniques for soft ground improvement

    Science.gov (United States)

    Bergado, D. T.; Long, P. V.; Chaiyaput, S.; Balasubramaniam, A. S.

    2018-04-01

    Soft ground improvement techniques have become most practical and popular methods to increase soil strength, soil stiffness and reduce soil compressibility including the soft Bangkok clay. This paper focuses on comparative performances of prefabricated vertical drain (PVD) using surcharge, vacuum and heat preloading as well as the cement-admixed clay of Deep Cement Mixing (DCM) and Stiffened DCM (SDCM) methods. The Vacuum-PVD can increase the horizontal coefficient of consolidation, Ch, resulting in faster rate of settlement at the same magnitudes of settlement compared to Conventional PVD. Several field methods of applying vacuum preloading are also compared. Moreover, the Thermal PVD and Thermal Vacuum PVD can increase further the coefficient of horizontal consolidation, Ch, with the associated reduction of kh/ks values by reducing the drainage retardation effects in the smear zone around the PVD which resulted in faster rates of consolidation and higher magnitudes of settlements. Furthermore, the equivalent smear effect due to non-uniform consolidation is also discussed in addition to the smear due to the mechanical installation of PVDs. In addition, a new kind of reinforced deep mixing method, namely Stiffened Deep Cement Mixing (SDCM) pile is introduced to improve the flexural resistance, improve the field quality control, and prevent unexpected failures of the Deep Cement Mixing (DCM) pile. The SDCM pile consists of DCM pile reinforced with the insertion of precast reinforced concrete (RC) core. The full scale test embankment on soft clay improved by SDCM and DCM piles was also analysed. Numerical simulations using the 3D PLAXIS Foundation finite element software have been done to understand the behavior of SDCM and DCM piles. The simulation results indicated that the surface settlements decreased with increasing lengths of the RC cores, and, at lesser extent, increasing sectional areas of the RC cores in the SDCM piles. In addition, the lateral movements

  7. Face resurfacing using a cervicothoracic skin flap prefabricated by lateral thigh fascial flap and tissue expander.

    Science.gov (United States)

    Li, Qingfeng; Zan, Tao; Gu, Bin; Liu, Kai; Shen, Guoxiong; Xie, Yun; Weng, Rui

    2009-01-01

    Resurfacing of facial massive soft tissue defect is a formidable challenge because of the unique character of the region and the limitation of well-matched donor site. In this report, we introduce a technique for using the prefabricated cervicothoracic skin flap for facial resurfacing, in an attempt to meet the principle of flap selection in face reconstructive surgery for matching the color and texture, large dimension, and thinner thickness (MLT) of the recipient. Eleven patients with massive facial scars underwent resurfacing procedures with prefabricated cervicothoracic flaps. The vasculature of the lateral thigh fascial flap, including the descending branch of the lateral femoral circumflex vessels and the surrounding muscle fascia, was used as the vascular carrier, and the pedicles of the fascial flap were anastomosed to either the superior thyroid or facial vessels in flap prefabrication. A tissue expander was placed beneath the fascial flap to enlarge the size and reduce the thickness of the flap. The average size of the harvested fascia flap was 6.5 x 11.7 cm. After a mean interval of 21.5 weeks, the expanders were filled to a mean volume of 1,685 ml. The sizes of the prefabricated skin flaps ranged from 12 x 15 cm to 15 x 32 cm. The prefabricated skin flaps were then transferred to the recipient site as pedicled flaps for facial resurfacing. All facial soft tissue defects were successfully covered by the flaps. The donor sites were primarily closed and healed without complications. Although varied degrees of venous congestion were developed after flap transfers, the marginal necrosis only occurred in two cases. The results in follow-up showed most resurfaced faces restored natural contour and regained emotional expression. MLT is the principle for flap selection in resurfacing of the massive facial soft tissue defect. Our experience in this series of patients demonstrated that the prefabricated cervicothoracic skin flap could be a reliable alternative

  8. Super-light Structures with Pearl-chain Reinforcement

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl; Bagger, Anne

    2010-01-01

    Steel structures are considered to be light compared to concrete structures. This paper presents a newly invented type of structure which is often light compared to steel structures, and therefore it is called "Super-light Structures", or SLS. The basic idea of SLS is to build a skeleton...... of prefabricated segments of a strong material, assembled by one or more prestressing wires. By means of pearl-chain reinforcement, it becomes affordable to provide structures with a wide variety of shapes. This allows a more resource-economical design, because it removes practical hindrances for application...

  9. Evaluating a Prefabricated Submerged Breakwater and Double-T Sill for Beach Erosion Prevention, Cape May Point, NJ

    National Research Council Canada - National Science Library

    Stauble, Donald K; Giovannozzi, Michael A

    2003-01-01

    ...) and a linear prefabricated concrete sill called the Double-T across the seaward end of two adjacent groin compartments, in order to assess the effectiveness of these structures in retaining sand...

  10. Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

    OpenAIRE

    Kim, Chang-Soon; Duong, Hieu Pham; Park, Jung-Chul; Shin, Hyun-Seung

    2016-01-01

    Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-...

  11. Off-Site Prefabrication: What Does it Require from the Trade Contractor?

    DEFF Research Database (Denmark)

    Bekdik, Baris; Hall, Daniel; Aslesen, Sigmund

    2016-01-01

    The purpose of the paper is to show what is required to industrialize a building process from the standpoint of the trade contractor. Rationalization of building processes has, over the years, caught the attention of numerous IGLC papers. Although significant contributions have been made to further...... understand and improve existing construction processes, relatively few contributions have focused on the opportunities for industrialization from the trade contractor’s perspective. This paper uses an in-depth case study to address the deployment strategy for off-site fabrication techniques and processes...... at only one case study, the conclusions are limited in generalizability to other prefabrication operations. However, it represents an important in-depth case from the trade contractors’ perspective and will contribute to the growing body of research focused on industrialization and prefabrication in lean...

  12. Study on Cooperative Mechanism of Prefabricated Producers Based on Evolutionary Game Theory

    Directory of Open Access Journals (Sweden)

    Tongyao Feng

    2017-01-01

    Full Text Available Good cooperation mechanism is an important guarantee for the advancement of industrialization construction. To strengthen the partnership between producers, we analyze the behavior evolution trend of both parties using an evolutionary game theory. Based on the original model, the mechanism of coordination and cooperation between prefabricated producers is explained under the condition of punishment and incentive. The results indicate that stable evolutionary strategies exist under both cooperation and noncooperation, and the evolutionary results are influenced by the initial proportion of both decision-making processes. The government can support the production enterprises to establish a solid partnership through effective punishment and incentive mechanisms to reduce the initial cost in the supply chain of prefabricated construction, resulting in a win-win situation.

  13. Utilization of Construction Waste Composite Powder Materials as Cementitious Materials in Small-Scale Prefabricated Concrete

    OpenAIRE

    Cuizhen Xue; Aiqin Shen; Yinchuan Guo; Tianqin He

    2016-01-01

    The construction and demolition wastes have increased rapidly due to the prosperity of infrastructure construction. For the sake of effectively reusing construction wastes, this paper studied the potential use of construction waste composite powder material (CWCPM) as cementitious materials in small-scale prefabricated concretes. Three types of such concretes, namely, C20, C25, and C30, were selected to investigate the influences of CWCPM on their working performances, mechanical properties, ...

  14. Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment

    OpenAIRE

    de Jesus Tavarez, Rudys Rodolfo; Bonachela, Wellington Cardoso; Xible, Anuar Antônio

    2011-01-01

    OBJECTIVES: The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. MATERIAL AND METHODS: Standard metal crowns were fabricated for 5 groups (n=10) of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricate...

  15. Evaluation of torque loss value of MAD/MAM zirconia abutments with prefabricated titanium abutments

    OpenAIRE

    Marzieh Alikhasi; Roshanak Baghaie; Nasim khosronejad

    2013-01-01

    Background and Aims: In response to esthetic demand of patients, ceramic abutments have been developed. Despite esthetic of zirconia abutments, machining accuracy of these abutments has always been a question. Any misfit in the abutment-implant interface connection can lead to detorque and screw loosening. The aim of this study was to compare torque loss value of manually aided design/manually aided manufacture (MAD/MAM) zirconia abutments with prefabricated titanium abutments. Materials and ...

  16. FEA of the Variations in Sound Insulation in Nominally Identical Prefabricated Lightweight Timber Panel Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Andersen, Lars

    2013-01-01

    The measurements of sound propagation in buildings usually show a variation between nominally identical constructed structures. These variations can be due to variations in structural properties, measurement uncertainties or workmanship related factors. Better knowledge about the source...... for these variations can lead to lowered production costs. The present paper presents a numerical analysis of the variations in sound propagation of norminally identical prefabricated lightweight timber panel structues. By using the commercial FEA software ABAQUS, a parameter study is carried out regarding variation...

  17. Powerful Software to Simulate Soil Consolidation Problems with Prefabricated Vertical Drains

    OpenAIRE

    Gonzalo García-Ros; Iván Alhama; Manuel Cánovas

    2018-01-01

    The present work describes the program Simulation of Consolidation with Vertical Drains (SICOMED_2018), a tool for the solution of consolidation processes in heterogeneous soils, with totally or partially penetrating prefabricated vertical drains (PVD) and considering both the effects of the smear zone, generated when introducing the drain into the ground, and the limitation in the discharge capacity of the drain. In order to provide a completely free program, the code Next-Generation Simulat...

  18. Use of dry sludge from waste water treatment plants as an additive in prefabricated concrete brick

    OpenAIRE

    Yagüe, A.; Valls, S.; Vázquez, E.; Kuchinow, V.

    2002-01-01

    Dry sludge from the Sabadell Water Treatment Plant was used to prepare prefabricated concrete bricks. After characterising the sludge and the manufacturing process used to make the bricks, we define the conditions of addition of the sludges in the manufacture. Reference samples not containing sludge and samples containing 2 % of dry sludge by cement weight were prepared. The variation in density, porosity, absorption coefficient and compressive strength of the bricks with the presence of...

  19. Ordering Strategy Analysis of Prefabricated Component Manufacturer in Construction Supply Chain

    OpenAIRE

    Yang, Hongxiong; Chung, Jacky K. H.; Chen, Yuhong; Pan, Yifan; Mei, Zhiling; Sun, Xiongle

    2018-01-01

    Firstly, the characteristics and present situations of the prefabricated construction supply chain are analyzed; inventory cost models for construction material of every phase order, one-off order, and fractionated order are built based on traditional EOQ model and construction supply chain theory. Next, the order decision is represented in binary numbers 0 and 1, in which 0 stands for “no order” and 1 for “order.” The analysis uses the genetic algorithm, sets the objective function, and unde...

  20. Prefabricated Images in Young Children’s Text-Making at School

    Directory of Open Access Journals (Sweden)

    Charlotte Engblom

    2016-08-01

    Full Text Available In classrooms where computers are used as tools for text-making, images and photographs from e.g. Google, here called “prefabricated images”, can be selected and copied into texts and combined with writing. In this article children’s use of prefabricated images as resources for personal texts is investigated with specific focus on cohesion between the modes of image and writing. When prefabricated images occur in combination with writing about a personal experience the specific motifs shown in the image are unrelated to the text-maker, but the results of this study show that cohesion may still be obtained, for example via colour, naturalistic modality or decontextualization of the motif in the image via a close-up or a distant perspective. Copying and recontextualization of photographs are common not only in schools but also in professional settings as image banks supply images to, for example, news editors and journalists, and contemporary text creation is often characterized by “representation-as-selection” (Adami and Kress, 2010. The ability to obtain cohesion across modes can be regarded as a defining feature of success in multimodal text-making (Wyatt-Smith and Kimber, 2009, and also for the interpretation of contemporary texts.

  1. Perforation of reinforced concrete walls by missiles

    International Nuclear Information System (INIS)

    Berriaud, C.; Verpeaux, P.

    1979-01-01

    The tests performed in France are presented together with the results obtained at the present time. Comparisons are made between test results and calculations. A bi-dimensional finite element program Plexus is used

  2. Comparación entre redes de fibras sintéticas y redes de fibras de cáñamo para el refuerzo de muros de albañileria = Comparison between synthetic fiber networks and hemp fiber networks for the reinforcement of masonry walls

    Directory of Open Access Journals (Sweden)

    Alessandra Vilardi

    2016-12-01

    Full Text Available La existencia de una gran cantidad de edificios antiguos ha movilizado la investigación para estudiar nuevos sistemas de refuerzo a aquellas construcciones que sean dañadas por decadencia fisiológica o por terremoto. El presente documento demuestra la eficacia de un sistema de refuerzo innovador para los muros de mampostería, constituyentes los elementos estructurales de los edificios históricos. Se hace una comparación entre unas redes bidireccionales de fibras sintéticas tradicionales y las de fibras naturales, ambas pegadas a las dos fachadas del muro con matriz de mortero. El resultado muestra la aplicación de las fibras de cáñamo como refuerzo sísmico y una mayor compatibilidad de estas con el material que caracterizan los edificios antiguos. Abstract The existence of a large number of old buildings has mobilized research to study new systems of reinforcement to those buildings that are damaged by physiological decay or earthquake. This document demonstrates the effectiveness of an innovative reinforcement system for masonry walls, which are the structural elements of historic buildings. A comparison is made between bidirectional networks of traditional synthetic fibers and those of natural fibers, both glued to the two facades of the wall with mortar matrix. The result shows the application of hemp fibers as seismic reinforcement and a greater compatibility of these with the material that characterize the old buildings.

  3. Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

    OpenAIRE

    Cumerlato, Marina; Lima, Eduardo Martinelli de; Osorio, Leandro Berni; Mota, Eduardo Gonçalves; Menezes, Luciane Macedo de; Rizzatto, Susana Maria Deon

    2017-01-01

    ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3,...

  4. Effect of surface treatment of prefabricated posts on bonding of resin cement

    DEFF Research Database (Denmark)

    Sahafi, Alireza; Peutzfeld, Anne; Asmussen, Erik

    2004-01-01

    This in vitro study evaluated the effect of various surface treatments of prefabricated posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White) and zirconia (Cerapost) on the bonding of two resin cements: ParaPost Cement and Panavia F by a diametral tensile strength (DTS) test...... the start of mixing the resin cement, the specimen was freed from the mold and stored in water at 37 degrees C for seven days. Following water storage, the specimen was wet-ground to a final length of approximately 3 mm. The DTS of specimens was determined in a Universal Testing Machine. The bonding...

  5. Custom-made prefabricated titanium miniplates in Le Fort I osteotomies: principles, procedure and clinical insights.

    Science.gov (United States)

    Philippe, B

    2013-08-01

    This paper describes a new type of miniplate system that is designed and custom made during virtual surgery planning based on an individual patient's osteotomy. These miniplates are prefabricated with commercially pure porous titanium using direct metal laser sintering. The principles that guide the conception and production of this new miniplate are presented. The surgical procedure from the stage of virtual surgery planning until the final Le Fort I osteotomy and bone fixation are described using a case example. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. Effect of custom-made and prefabricated insoles on plantar loading parameters during running with and without fatigue.

    Science.gov (United States)

    Lucas-Cuevas, Angel Gabriel; Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Macián-Romero, Cecili; Sánchez-Zuriaga, Daniel

    2014-01-01

    Controversy exists whether custom-made insoles are more effective in reducing plantar loading compared to prefabricated insoles. Forty recreational athletes ran using custom-made, prefabricated, and the original insoles of their running shoes, at rest and after a fatigue run. Contact time, stride rate, and plantar loading parameters were measured. Neither the insole conditions nor the fatigue state modified contact time and stride rate. Addressing prevention of running injuries, post-fatigue loading values are of great interest. Custom-made insoles reduced the post-fatigue loading under the hallux (92 vs. 130 kPa, P heel compared to the prefabricated insoles. Finally, fatigue state did not influence plantar loading regardless the insole condition. In long-distance races, even a slight reduction in plantar loading at each foot strike may suppose a significant decrease in the overall stress experienced by the foot, and therefore the use of insoles may be an important protective mechanism for plantar overloading.

  7. Comparison of plantar pressure distribution in CAD-CAM and prefabricated foot orthoses in patients with flexible flatfeet.

    Science.gov (United States)

    Khodaei, Banafsheh; Saeedi, Hassan; Jalali, Maryam; Farzadi, Maede; Norouzi, Ehsan

    2017-12-01

    The effect of foot orthoses on plantar pressure distribution has been proven by researchers but there are some controversies about advantages of custom-made foot orthoses to less expensive prefabricated foot orthoses. Nineteen flatfeet adults between 18 and 45 participated in this study. CAD-CAM foot orthoses were made for these patients according to their foot scan. Prefabricated foot orthoses were prepared according to their foot size. Plantar pressure, force and contact area were measured using pedar ® -x in-shoe system wearing shoe alone, wearing CAD-CAM foot orthoses and wearing prefabricated foot orthoses. Repeated measures ANOVA model with post-hoc, Bonferroni comparison were used to test differences. CAD-CAM and prefabricated foot orthoses both decreased pressure and force under 2nd, 3-5 metatarsal and heel regions comparing to shoe alone condition. CAD-CAM foot orthosis increased pressure under lateral toe region in comparison to shoe alone and prefabricated foot orthosis. Both foot orthoses increased pressure and contact area in medial midfoot region comparing to shoe alone condition. Increased forces were seen at hallux and lateral toes by prefabricated foot orthoses in comparison with CAD-CAM foot orthoses and control condition, respectively. According to the results, both foot orthoses could decrease the pressure under heel and metatarsal area. It seems that the special design of CAD-CAM foot orthoses could not make great differences in plantar pressure distribution in this sample. Further research is required to determine whether these results are associated with different scan systems or design software. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A new method of prefabricated vascularized allogenic bone grafts for maxillo-mandibular reconstruction

    International Nuclear Information System (INIS)

    Pill-Hoon Choung

    1999-01-01

    Although there are various applications of allogenic bone grafts, a new technique of prevascularized lyophilized allogenic bone grafting for maxillo-mandibular reconstruction will be presented. Allogenic bone has been made by author's protocol for jaw defects as a powder, chip or block bone type. The author used lyophilized allogenic bone grafts for discontinuity defects as a block bone. In those cases, neovascularization and resorption of the allogenic bone were important factors for success of grafting. To overcome the problems, the author designed the technique of prefabricated vascularization of allogenic bone, which was lyophilized cranium, with an application of bovine BMP or not. Lyophilized cranial bone was designed for the defects and was put into the scalp. After confirming a hot spot via scintigram several months later, vascularized allogenic bone was harvested pedicled on the parietotemporal fascia based on the superficial temporal artery and vein. Vascularized allogenic cranial bone was rotated into the defect and fixed rigidly. Postoperatively, there was no severe resorption and functional disturbance of the mandible. In this technique, BMP seems to be an important role to help osteogenesis and neovascularization. Eight patients underwent prefabricated vascularization of allogenic bone grafts. Among them, four cases of reconstruction in mandibular discontinuity defects and one case of reconstruction in maxillectomy defect underwent this method, which will be presented with good results. This method may be an alternative technique of microvascular free bone graft

  9. Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: A better model

    International Nuclear Information System (INIS)

    Dong Qingshan; Shang Hongtao; Wu Wei; Chen Fulin; Zhang Junrui; Guo Jiaping; Mao Tianqiu

    2012-01-01

    The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone. - Highlights: ► A modified arteriovenous loop (AVL) model in rabbit was developed in this study. ► Axial prevascularization was induced in a larger coral block by using the AVL. ► The prefabrication of axial vascularized coral bone is superior as vascular carrier.

  10. REINFORCED COMPOSITE PANEL

    DEFF Research Database (Denmark)

    2003-01-01

    A composite panel having front and back faces, the panel comprising facing reinforcement, backing reinforcement and matrix material binding to the facing and backing reinforcements, the facing and backing reinforcements each independently comprising one or more reinforcing sheets, the facing rein...... by matrix material, the facing and backing reinforcements being interconnected to resist out-of-plane relative movement. The reinforced composite panel is useful as a barrier element for shielding structures, equipment and personnel from blast and/or ballistic impact damage....

  11. Slipforming of reinforced concrete shield building

    International Nuclear Information System (INIS)

    Hsieh, M.C.; King, J.R.

    1982-01-01

    The unique design and construction features of slipforming the heavily reinforced concrete cylindrical shield walls at the Satsop nuclear plant in Washington, D.C. site are presented. The shield walls were designed in compliance with seismic requirements which resulted in the need for reinforcing steel averaging 326 kg/m/sup 3/. A 7.6 m high, three-deck moving platform was designed to permit easy installation of the reinforcing steel, embedments, and blockouts, and to facilitate concrete placement and finishing. Two circular box trusses, one on each side of the shield wall, were used in combination with a spider truss to meet both the tolerance and strength requirements for the slipform assembly

  12. Heat Storage Performance of the Prefabricated Hollow Core Concrete Deck Element with Integrated Microencapsulated Phase Change Material

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    The paper presents the numerically calculated dynamic heat storage capacity of the prefabricated hollow core concrete deck element with and without microencapsulated phase change material (PCM). The reference deck is the ordinary deck made of standard concrete material and that is broadly used...

  13. A Market Equilibrium Supply Chain Model for Supporting Self-Manufacturing or Outsourcing Decisions in Prefabricated Construction

    Directory of Open Access Journals (Sweden)

    Yanhu Han

    2017-11-01

    Full Text Available Prefabricated construction is a sustainable alternative to traditional on-site construction methods. However, many challenges still exist in the prefabricated construction process. For example, self-manufacturing or outsourcing decisions are vital to the industrial structure and organization of the prefabricated construction industry, and the company’s production and operation decision-making. This paper considers a prefabricated construction supply chain, which is composed of one upstream component manufacturing company and two downstream contractors. The large contractor can get the precast component through self-manufacturing or outsourcing, while the small and medium-sized enterprise (SME contractor can only buy components from the component manufacturer. A comprehensive game model (Cournot-Stackelberg model under different decisions, that is, component self-manufacturing or outsourcing, was established. By solving the profit functions of different companies in the prefabricated construction supply chain, the equilibrium solutions of output, price and profit can be achieved. These solutions of equilibrium indicate the optimal decision on the production and operation, and the profit’s boundary conditions. After assuming relevant parameters, the profit levels of the companies in the supply chain are analyzed via a dynamic simulation in the changing process of prefabricated construction market size under different behavioral decisions. The conclusions are as follows: (1 the profit levels of all supply chain enterprises and the whole supply chain are increasing with an increase of market size; (2 the downstream contractors and the whole supply chain have a higher profit level under the component self-manufacturing decision, however, on the contrary, the upstream component suppliers get a higher profit level under the component outsourcing decision; (3 the equilibrium output of the SME contractor is reduced under the outsourcing decision of

  14. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS

    International Nuclear Information System (INIS)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-01-01

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits

  15. Seismic Stability of Reinforced Soil Slopes

    DEFF Research Database (Denmark)

    Tzavara, I.; Zania, Varvara; Tsompanakis, Y.

    2012-01-01

    Over recent decades increased research interest has been observed on the dynamic response and stability issues of earth walls and reinforced soil structures. The current study aims to provide an insight into the dynamic response of reinforced soil structures and the potential of the geosynthetics...... to prevent the development of slope instability taking advantage of their reinforcing effect. For this purpose, a onedimensional (SDOF) model, based on Newmark’s sliding block model as well as a two-dimensional (plane-strain) dynamic finite-element analyses are conducted in order to investigate the impact...

  16. Transparent thermal insulation for prefabricated school buildings; Einsatz transparenter Waermedaemmung an Schulgebaeuden in praefabrizierter Bauweise

    Energy Technology Data Exchange (ETDEWEB)

    Russ, C. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany). Gruppe Solares Bauen; Buchmann, R. [Leipzigprojekt GmbH, Leipzig (Germany); Duesterhoeft, A. [Holz- und Leichtmetallbau GmbH, Leipzig (Germany)

    1997-12-31

    The existing schools in the new federal states built from prefabricated elements need to be modernized in order to reduce their energy demand. Fitting some 300 square metres of transparent thermal insulation to the south side of a house front may lead to a cut in its thermal energy demand by 74 per cent. This energy consumption is by 12 kWh per square metre lower than the one obtained with opaque thermal insulation. The results of the first demonstration project are described. (MSK) [Deutsch] Die in den neuen Bundeslaendern vorhandenen Schulen in vorgefertigter Bauweise sind energetisch sanierungsbeduerftig. Werden im Rahmen einer Sanierung ca. 300qm transparente Waermedaemmung an der suedorientierten Fassade eingesetzt, so kann der Heizwaermebedarf um 74% herabgesetzt werden. Das sind 12 kWh/qm weniger als bei dem vergleichsweisen Einsatz einer opaken Waermedaemmung. Im Folgenden werden die Ergebnisse des ersten Demonstrationsprojekts beschrieben.

  17. Investigation on effectiveness of a prefabricated vertical drain during cyclic loading

    International Nuclear Information System (INIS)

    Indraratna, B; Ni, J; Rujikiatkamjorn, C

    2010-01-01

    The effectiveness of prefabricated vertical drains (PVDs) in enhancing the stability of soft soils during cyclic loading was investigated using triaxial cyclic loading tests. Both undrained and with PVD tests were employed to study the associated excess pore pressure and accumulated strain under the repeated loading condition. The loading frequency and cyclic stress ratio have been chosen to be the variables which influence the performance of soft clays. The experimental results illustrate that with PVDs, the excess pore water pressure generation during cyclic loading decreases significantly. It is found that the excess pore water pressure build up depends on both loading frequency and cyclic stress ratio. The excess pore water pressure will increase when each of them is increased. Furthermore, when the loading frequency is 0.1 Hz, the ratio of coefficient of consolidation under cyclic loading to that under static loading is almost one. With the increasing loading frequency, this ratio increases accordingly.

  18. Modern housing design: prefabricated and modular design in Frank Lloyd Wright's architecture

    Directory of Open Access Journals (Sweden)

    Ana Tagliari

    2011-12-01

    Full Text Available This paper investigates the residential architecture of Frank Lloyd Wright, especially the designs which were conceived from an idea of prefabricated, modular, low-cost, and high-scale construction. Wright's organic designs originated from a material-based grid, which at the same time organized and provided freedom to create spaces and forms. This study reviews Wright's work, from his first Midwest designs that relied on brick, through an intermediary phase in California when he made intense use of concrete blocks, until his last phase, the usonian houses, which featured wood paneling. During his early career, the concept and the methodology of Wright's ideas greatly contributed to a better understanding of his architecture, his apprentices and his followers. The economy and rationalization found in the projects reviewed are of great importance as the analysis of historical proposals helps us understand the topic in question.

  19. The Effect of Pre-teaching Extended Prefabricated Lexical Bundles on the Writing Development of

    Directory of Open Access Journals (Sweden)

    Seiyed Mahdi Araghi

    2014-03-01

    Full Text Available This study attempts to shed light on how a teacher’s instruction and guidance can cast aside writing inhibitions and bring about remarkable changes in the writing ability of advanced EFL students through the collaborative construction of extended chunks of language with the aim of enhancing lexical density and complexity and consequently injecting into learners a sense of satisfaction with their work. The sample included 40 TOEFL students selected out of 75 TOEFL students on the basis of their scores on a TOEFL test. The participants were randomly assigned into two groups-the control group and experimental group. After 20 instructional sessions both groups were assigned five writing tasks. The results reveal that the participants in experimental group outperformed their counterparts in control group. Overall, it is concluded that pre-teaching extended prefabricated lexical bundles can be a useful means of helping advanced students to improve their writing quality.

  20. Habituation of reinforcer effectiveness

    OpenAIRE

    David R Lloyd; David R Lloyd; Douglas J Medina; Larry W Hawk; Whitney D Fosco; Jerry B Richards

    2014-01-01

    In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral and neural based explanations of reinforcement. We argue that habituation of reinforcer effectiveness (HRE) is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We ar...

  1. The structural study of prefabrication stress stent and the hemodynamics in percutaneous transhepatic portacaval shunt

    International Nuclear Information System (INIS)

    Chu Jianguo; Sun Xiaoli; Zhou Yijun; Huang He; Zhou Hua; Lv Chunyan; Yang Shuhui

    2006-01-01

    Objective: To present a preliminary latest procedure for portal hypertension and evaluate the technical feasibility and efficacy of portacaval shunt creation through the percutaneous transhepatic approach in order to make a hemodynamic comparison with that of the classic TIPS. Methods: Thirty-eight patients with portal hypertension (36 men; mean age 57 years, range 32-73) were referred for PTPS procedure because of bleeding varices (n=36), intractable ascites (n=1), and hepatopulmonary syndrome (n=1). The severity of liver disease was classified as Child-Pugh B in 27 and C in 11. The PTPS was created by a percutaneous transhepatic puncture into right portal vein and then through left portal vein to the hepatic segment of IVC followed by a prefabrication stress stent-graft placement at the very site. Results: Technical and functional success of 100% was achieved in all patients, without related complications. The postprocedural portal vein-IVC gradients mean 13 cmH 2 O was achieved with the follow-up period mean 493 days. No recurrence of variceal bleeding and controlled refractory ascites were achieved, and still more with primary patency rate of the involved vascular structure up to 94.8% at 365 days, much better than classic TIPS. Conclusions: Portacaval shunt creation using the prefabrication stress stent via percutaneous transhepatic technique is safe and feasible. the compact coincidence was obtained between the stent and the involved vessel with restoration of intrahepatic portal venous hemodynamics together with partial lowering of portal venous pressure and guaranteeing intrahepatic perfusion through right portal vein. It is also obviously to have postoperative prevention of shunt restenoses and lowering postoperative incidence of hepato-encephalopathy. (authors)

  2. Performance of Modular Prefabricated Architecture: Case Study-Based Review and Future Pathways

    Directory of Open Access Journals (Sweden)

    Fred Edmond Boafo

    2016-06-01

    Full Text Available Even though tightened building energy efficiency standards are implemented periodically in many countries, existing buildings continually consume a momentous quota of the total primary energy. Energy efficiency solutions range from material components to bulk systems. A technique of building construction, referred to as prefabricated architecture (prefab, is increasing in reputation. Prefab encompasses the offsite fabrication of building components to a greater degree of finish as bulk building structures and systems, and their assembly on-site. In this context, prefab improves the speed of construction, quality of architecture, efficiency of materials, and worker safety, while limiting environmental impacts of construction, as compared to conventional site-built construction practices. Quite recently, a 57 story skyscraper was built in 19 days using prefabricated modules. From the building physics point of view, the bulk systems and tighter integration method of prefab minimizes thermal bridges. This study seeks to clearly characterize the levels of prefab and to investigate the performance of modular prefab; considering acoustic constrain, seismic resistance, thermal behavior, energy consumption, and life cycle analysis of existing prefab cases and, thus, provides a dynamic case study-based review. Generally, prefab can be categorized into components, panels (2D, modules (3D, hybrids, and unitized whole buildings. On average, greenhouse gas emissions from conventional construction were higher than for modular construction, not discounting some individual discrepancies. Few studies have focused on monitored data on prefab and occupants’ comfort but additional studies are required to understand the public’s perception of the technology. The scope of the work examined will be of interest to building engineers, manufacturers, and energy experts, as well as serve as a foundational reference for future study.

  3. Numerical investigation on the prefabricated crack propagation of FV520B stainless steel

    Directory of Open Access Journals (Sweden)

    Juyi Pan

    Full Text Available FV520B is a common stainless steel for manufacturing centrifugal compressor impeller and shaft. The internal metal flaw destroys the continuity of the material matrix, resulting in the crack propagation fracture of the component, which seriously reduces the service life of the equipment. In this paper, Abaqus software was used to simulate the prefabricated crack propagation of FV520B specimen with unilateral gap. The results of static crack propagation simulation results show that the maximum value of stress–strain located at the tip of the crack and symmetrical distributed like a butterfly along the prefabricated crack direction, the maximum stress is 1990 MPa and the maximum strain is 9.489 × 10−3. The Mises stress and stress intensity factor KI increases with the increase of the expansion step, the critical value of crack initiation is reached at the 6th extension step. The dynamic crack propagation simulation shows that the crack propagation path is perpendicular to the load loading direction. Similarly, the maximum Mises stress located at the crack tip and is symmetrically distributed along the crack propagation direction. The critical stress range of the crack propagation is 23.3–43.4 MPa. The maximum value of stress–strain curve located at the 8th extension step, that is, the crack initiation point, the maximum stress is 55.22 MPa, and the maximum strain is 2.26 × 10−4. On the crack tip, the stress changed as 32.24–40.16 MPa, the strain is at 1.292 × 10−4–1.897 × 10−4. Keywords: FV520B, Crack propagation, Mises stress, Stress–strain, Numerical investigation

  4. Flexural reinforced concrete member with FRP reinforcement

    OpenAIRE

    Putzolu, Mariana

    2017-01-01

    One of the most problematic point in construction is the durability of the concrete especially related to corrosion of the steel reinforcement. Due to this problem the construction sector, introduced the use of Fiber Reinforced Polymer, the main fibers used in construction are Glass, Carbon and Aramid. In this study, the author aim to analyse the flexural behaviour of concrete beams reinforced with FRP. This aim is achieved by the analysis of specimens reinforced with GFRP bars, with theoreti...

  5. Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

    2015-01-01

    The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented...

  6. Reinforced sulphur concrete

    NARCIS (Netherlands)

    2014-01-01

    Reinforced sulphur concrete wherein one or more metal reinforcing members are in contact with sulphur concrete is disclosed. The reinforced sulphur concrete comprises an adhesion promoter that enhances the interaction between the sulphur and the one or more metal reinforcing members.

  7. The visual image of prefabricated houses and new directions in the urban and architectural development of settlements

    Directory of Open Access Journals (Sweden)

    Živa Deu

    2000-01-01

    Full Text Available On the basis of the general directions of sustainable development in the physical space, new, also detailed valuable and normative definitions for organising settlements have been defined. Urban design and architectural aspects are directed to planning according to given natural possibilities and typical form and identity of built structures. Studies and detailed analyses have shown that formerly established standards of the building culture consist of numerous valuable characteristics, which are in accordance with the principles of sustainable development. Prefabricated building, just like classical building, is a constituent part of the new process in the formation of settlements. To attain our goal, radical changes will be needed in the architectural design of prefabricated houses, because their present architecture is global, cosmopolitan and not adapted to the different natural conditions and existing typical built structures in Slovenia.

  8. Design of online monitoring and forecasting system for electrical equipment temperature of prefabricated substation based on WSN

    Science.gov (United States)

    Qi, Weiran; Miao, Hongxia; Miao, Xuejiao; Xiao, Xuanxuan; Yan, Kuo

    2016-10-01

    In order to ensure the safe and stable operation of the prefabricated substations, temperature sensing subsystem, temperature remote monitoring and management subsystem, forecast subsystem are designed in the paper. Wireless temperature sensing subsystem which consists of temperature sensor and MCU sends the electrical equipment temperature to the remote monitoring center by wireless sensor network. Remote monitoring center can realize the remote monitoring and prediction by monitoring and management subsystem and forecast subsystem. Real-time monitoring of power equipment temperature, history inquiry database, user management, password settings, etc., were achieved by monitoring and management subsystem. In temperature forecast subsystem, firstly, the chaos of the temperature data was verified and phase space is reconstructed. Then Support Vector Machine - Particle Swarm Optimization (SVM-PSO) was used to predict the temperature of the power equipment in prefabricated substations. The simulation results found that compared with the traditional methods SVM-PSO has higher prediction accuracy.

  9. Predictors of response to prefabricated foot orthoses or rocker-sole footwear in individuals with first metatarsophalangeal joint osteoarthritis

    OpenAIRE

    Menz, HB; Auhl, M; Tan, JM; Levinger, P; Roddy, E; Munteanu, SE

    2017-01-01

    BACKGROUND: Osteoarthritis of the first metatarsophalangeal joint (1st MTPJ OA) is a common and disabling condition commonly managed with footwear and orthotic interventions. The objective of this study was to identify factors associated with a successful treatment response in people with 1st MTPJ OA provided with prefabricated orthoses or rocker-sole footwear as part of a randomised clinical trial. METHODS: People with 1st MTPJ OA (n = 88) who participated in a randomised trial were allocate...

  10. Three-dimensional modelling of an embankment built on a soft soil improved with prefabricated vertical drains

    OpenAIRE

    Venda Oliveira, P.J.; Cruz, R.F.P.M.L.; Lemos, L.J.L.; Almeida e Sousa, J.N.V.

    2015-01-01

    This work compares the field measurements of a non-symmetric embankment built on a Portuguese soft soil improved with prefabricated vertical drains (PVDs), with the numerical predictions of a 3D modelling where the PVDs are simulated according to the field flow conditions. The change in the permeability with the void ratio and the effect of the smear zone are also included in the numerical analysis. The numerical predictions are compared with the field data in terms of settlement, horizontal ...

  11. En bloc prefabrication of vascularized bioartificial bone grafts in sheep and complete workflow for custom-made transplants.

    Science.gov (United States)

    Kokemüller, H; Jehn, P; Spalthoff, S; Essig, H; Tavassol, F; Schumann, P; Andreae, A; Nolte, I; Jagodzinski, M; Gellrich, N-C

    2014-02-01

    The aim of this pilot study was to determine, in a new experimental model, whether complex bioartificial monoblocs of relevant size and stability can be prefabricated in a defined three-dimensional design, in which the latissimus dorsi muscle serves as a natural bioreactor and the thoracodorsal vessel tree is prepared for axial construct perfusion. Eighteen sheep were included in the study, with six animals in each of three experimental groups. Vitalization of the β-tricalcium phosphate-based constructs was performed by direct application of unmodified osteogenic material from the iliac crest (group A), in vivo application of nucleated cell concentrate (NCC) from bone marrow aspirate (group B), and in vitro cultivation of bone marrow stromal cells (BMSC) in a perfusion bioreactor system (group C). The contours of the constructs were designed digitally and transferred onto the bioartificial bone grafts using a titanium cage, which was bent over a stereolithographic model of the defined subvolume intraoperatively. At the end of the prefabrication process, only the axial vascularized constructs of group A demonstrated vital bone formation with considerable stability. In groups B and C, the applied techniques were not able to induce ectopic bone formation. The presented computer-assisted workflow allows the prefabrication of custom-made bioartificial transplants. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Pre-fabricated nanorods in RE–Ba–Cu–O superconductors

    International Nuclear Information System (INIS)

    Khatri, N D; Majkic, G; Shi, T; Selvamanickam, V; Chen, Y

    2013-01-01

    Pre-fabrication of metallic nanorods on biaxially textured templates has been explored in this study to introduce flux pinning centers in RE–Ba–Cu–O (REBCO, RE =rare earth) based superconductors. Pt nanorods were deposited by an electron beam assisted deposition method on LaMnO 3 -capped biaxially textured IBAD-(ion beam assisted deposition) substrates. Well-controlled nanorods with varying diameter (50–120 nm), length (up to 1 μm), orientation and unit cell size were grown over an area of 120–150 μm 2 . The nanorod-decorated samples were then deposited with Gd–Y–Ba–Cu–O ((Gd, Y)BCO) by metal organic chemical vapor deposition (MOCVD). The Pt nanorods remain in their positions during MOCVD and become embedded in the (Gd, Y)BCO matrix, although they suffer creep-induced shape deformation due to exposure to elevated temperature. Higher unit cell size, longer nanorods, and nanorods oriented at an angle to the substrate normal adversely affect the epitaxy of the (Gd, Y)BCO film due to formation of a-axis grains. The observed current-carrying capacity of the Pt nanorod sample is lower than its corresponding reference sample without any nanorods and processed under identical conditions, but it decreases at a slower rate with increasing magnetic field. Potential routes to improve the performance while retaining the desirable characteristics of controlled nanorod direction and density are discussed. (paper)

  13. Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Cumerlato, Marina; Lima, Eduardo Martinelli de; Osorio, Leandro Berni; Mota, Eduardo Gonçalves; Menezes, Luciane Macedo de; Rizzatto, Susana Maria Deon

    2017-01-01

    The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey's test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn's test. Surface treatments on PfT enhanced SBS of brackets (pgrinding) (pgrinding. There was a positive correlation between SBS and ARI.

  14. Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: a better model.

    Science.gov (United States)

    Dong, Qing-shan; Shang, Hong-tao; Wu, Wei; Chen, Fu-lin; Zhang, Jun-rui; Guo, Jia-ping; Mao, Tian-qiu

    2012-08-01

    The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Utilization of Construction Waste Composite Powder Materials as Cementitious Materials in Small-Scale Prefabricated Concrete

    Directory of Open Access Journals (Sweden)

    Cuizhen Xue

    2016-01-01

    Full Text Available The construction and demolition wastes have increased rapidly due to the prosperity of infrastructure construction. For the sake of effectively reusing construction wastes, this paper studied the potential use of construction waste composite powder material (CWCPM as cementitious materials in small-scale prefabricated concretes. Three types of such concretes, namely, C20, C25, and C30, were selected to investigate the influences of CWCPM on their working performances, mechanical properties, and antipermeability and antifrost performances. Also the effects of CWCPM on the morphology, hydration products, and pore structure characteristics of the cement-based materials were analyzed. The results are encouraging. Although CWCPM slightly decreases the mechanical properties of the C20 concrete and the 7 d compressive strengths of the C25 and C30 concretes, the 28 d compressive strength and the 90 d flexural strength of the C25 and C30 concretes are improved when CWCPM has a dosage less than 30%; CWCPM improves the antipermeability and antifrost performances of the concretes due to its filling and pozzolanic effects; the best improvement is obtained at CWCPM dosage of 30%; CWCPM optimizes cement hydration products, refines concrete pore structure, and gives rise to reasonable pore size distribution, therefore significantly improving the durability of the concretes.

  16. Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment

    Science.gov (United States)

    DE JESUS TAVAREZ, Rudys Rodolfo; BONACHELA, Wellington Cardoso; XIBLE, Anuar Antônio

    2011-01-01

    Objective The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. Material and Methods Standard metal crowns were fabricated for 5 groups (n=10) of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricated abutment; Group 4, external hexagon implant and UCLA cast-on premachined abutment; and Group 5, external hexagon implant and Ceraone abutment. For groups 1, 2, 3 and 5, the crowns were cemented on the abutments and in group 4 crowns were screwed directly on the implant. The specimens were subjected to 500,000 cycles at 19.1 Hz of frequency and non-axial load of 133 N in a MTS 810 machine. The vertical misfit (μm) at the implant/abutment interface was evaluated before (B) and after (A) application of the cyclic loading. Data were analyzed statistically by using two-away ANOVA and Tukey’s post-hoc test (pabutment connection may develop a role on the vertical misfit at the implant/abutment interface. PMID:21437464

  17. Carbon footprint hotspots of prefabricated sandwich panels for hostel construction in Perlis

    Science.gov (United States)

    Razali, Norashikin; Ayob, Afizah; Chandra, Muhammad Erwan Shah; Zaki, Mohd Faiz Mohammad; Ahmad, Abdul Ghapar

    2017-10-01

    Sustainable design and construction have gained increasing research interest, and reduction of carbon from building construction has become the main focus of environmental strategies in Malaysia. This study uses life cycle assessment and life cycle inventory analysis frameworks to estimate the amount of carbon footprint expressed in carbon dioxide equivalent tons (CO2e) produced by manufacturing prefabricated Industrialized Building System sandwich panels and its installation for a five-story hostel in Perlis, Malaysia. Results show that the carbon footprint hotspots were centered on boiler machine operation and cement with 4.52 and 369.04 tons CO2e, respectively. This finding is due to the extensive energy used for steam heating and high engine rating for the boiler. However, for cement, the carbon footprint hotspots are caused by the large quantity of cement applied in shotcrete mixture and its high extraction and production CO2 emission values. The overall onsite materials generated 96.36% of the total carbon footprint. These carbon footprint hotspot results constitute a necessary base for the Malaysian government in accomplishing an adequate dimensioning of carbon emissions in the building sector.

  18. Bond strength of stainless steel orthodontic brackets bonded to prefabricated acrylic teeth.

    Science.gov (United States)

    Wan Abdul Razak, Wan Salbiah; Sherriff, Martyn; Bister, Dirk; Seehra, Jadbinder

    2017-06-01

    The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Šidak's adjustment) were undertaken. The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.

  19. Powerful Software to Simulate Soil Consolidation Problems with Prefabricated Vertical Drains

    Directory of Open Access Journals (Sweden)

    Gonzalo García-Ros

    2018-02-01

    Full Text Available The present work describes the program Simulation of Consolidation with Vertical Drains (SICOMED_2018, a tool for the solution of consolidation processes in heterogeneous soils, with totally or partially penetrating prefabricated vertical drains (PVD and considering both the effects of the smear zone, generated when introducing the drain into the ground, and the limitation in the discharge capacity of the drain. In order to provide a completely free program, the code Next-Generation Simulation Program with Integrated Circuit Emphasis (Ngspice has been used as a numerical tool while the Matrix Laboratory (MATLAB code was used to program and create an interface with the user through interactive screens. In this way, SICOMED_2018 is presented as an easy-to-use and intuitive program, with a simple graphical interface that allows the user to enter all the soil properties and geometry of the problem without having to resort to a complex software package that requires programming. Illustrative applications describe both the versatility of the program and the reliability of its numerical solutions.

  20. Evolution of the Stability Work from Classic Retaining Walls to Mechanically Stabilized Earth Walls

    Directory of Open Access Journals (Sweden)

    Anghel Stanciu

    2008-01-01

    Full Text Available For the consolidation of soil mass and the construction of the stability works for roads infrastructure it was studied the evolution of these kinds of works from classical retaining walls - common concrete retaining walls, to the utilization in our days of the modern and competitive methods - mechanically stabilized earth walls. Like type of execution the variety of the reinforced soil is given by the utilization of different types of reinforcing inclusions (steel strips, geosynthetics, geogrids or facing (precast concrete panels, dry cast modular blocks, metal sheets and plates, gabions, and wrapped sheets of geosynthetics.

  1. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

  2. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how walls...... have encouraged architectural thinking of enclosure, materiality, construction and inhabitation in architectural history, the paper’s aim is to define new directions for the integration of LEDs in walls, challenging the thinking of inhabitation and program. This paper introduces the notion...... of “ambiguous walls” as a more “critical” approach to design [1]. The concept of ambiguous walls refers to the diffuse status a lumious and possibly responsive wall will have. Instead of confining it can open up. Instead of having a static appearance, it becomes a context over time. Instead of being hard...

  3. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  4. Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Marina Cumerlato

    Full Text Available ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT on the shear bond strength (SBS of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI. Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48: Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01, result not observed with ageing (p= 0.45. Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05. SBS was greater in the groups 3 and 4 (drilling, sandblasting than in the Group 2 (grinding (p< 0.05. SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05. Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI.

  5. Particulate Matter Mass Concentration in Residential Prefabricated Buildings Related to Temperature and Moisture

    Science.gov (United States)

    Kraus, Michal; Juhásová Šenitková, Ingrid

    2017-10-01

    Building environmental audit and the assessment of indoor air quality (IAQ) in typical residential buildings is necessary process to ensure users’ health and well-being. The paper deals with the concentrations on indoor dust particles (PM10) in the context of hygrothermal microclimate in indoor environment. The indoor temperature, relative humidity and air movement are basic significant factors determining the PM10 concentration [μg/m3]. The experimental measurements in this contribution represent the impact of indoor physical parameters on the concentration of particulate matter mass concentration. The occurrence of dust particles is typical for the almost two-thirds of interiors of the buildings. Other parameters indoor environment, such as air change rate, volume of the room, roughness and porosity of the building material surfaces, static electricity, light ions and others, were set constant and they are not taken into account in this study. The mass concentration of PM10 is measured during summer season in apartment of residential prefabricated building. The values of global temperature [°C] and relative humidity of indoor air [%] are also monitored. The quantity of particulate mass matter is determined gravimetrically by weighing according to CSN EN 12 341 (2014). The obtained results show that the temperature difference of the internal environment does not have a significant effect on the concentration PM10. Vice versa, the difference of relative humidity exhibits a difference of the concentration of dust particles. Higher levels of indoor particulates are observed for low values of relative humidity. The decreasing of relative air humidity about 10% caused 10µg/m3 of PM10 concentration increasing. The hygienic limit value of PM10 concentration is not exceeded at any point of experimental measurement.

  6. Marginal Productivity Gained Through Prefabrication: Case Studies of Building Projects in Auckland

    Directory of Open Access Journals (Sweden)

    Wajiha Shahzad

    2015-02-01

    Full Text Available Several studies have documented benefits of prefabrication system (prefab compared to the traditional building system (TBS. However, the documented benefits have been anecdotal or fragmented with reports of isolated case study projects. Few studies have looked at the objectively quantified benefits from statistical significance point of view and across building types in New Zealand. This study contributes to filling this knowledge gap by analyzing cost and time-savings, and productivity improvement achievable by the use of prefab in place of the TBS. Records of completion times and final contract values of 66 building projects implemented using prefab in Auckland were collected. The building types included commercial, houses, apartments, educational, and community buildings. The project details included final contract sums, completion dates, gross floor areas, and number of floors. Based on these details, the equivalent completion times and the final cost estimates for similar buildings implemented using the TBS were obtained from the Rawlinsons construction data handbook and feedback from some designers and contractors. Marginal productivity outcome for each building project was computed as the product of the cost and time-savings achieved using the prefab. Results showed that the use of prefab in place of TBS resulted in 34% and 19% average reductions in the completion times and costs, respectively. This also translated to overall 7% average improvement in the productivity outcomes in the building projects. Univariate ANOVA-based hypothesis test results showed that ‘building type’ had no significant effects on the cost and productivity improvement outcomes, but had significant effect on the time savings analyzed in the case study projects. The greatest productivity gain of 11% was achieved in house projects. These evidence-based results could guide optimized use of prefab for specific building application. The hypothesis-testing outcome

  7. CHANGES IN PATELLOFEMORAL JOINT STRESS DURING RUNNING WITH THE APPLICATION OF A PREFABRICATED FOOT ORTHOTIC.

    Science.gov (United States)

    Almonroeder, Thomas G; Benson, Lauren C; O'Connor, Kristian M

    2015-12-01

    Foot orthotics are commonly utilized in the treatment of patellofemoral pain (PFP) and have shown clinical benefit; however, their mechanism of action remains unclear. Patellofemoral joint stress (PFJS) is thought to be one of the main etiological factors associated with PFP. The primary purpose of this study was to investigate the effects of a prefabricated foot orthotic with 5 ° of medial rearfoot wedging on the magnitude and the timing of the peak PFJS in a group of healthy female recreational athletes. The hypothesis was that there would be significant reduction in the peak patellofemoral joint stress and a delay in the timing of this peak in the orthotic condition. Cross-sectional. Kinematic and kinetic data were collected during running trials in a group of healthy, female recreational athletes. The knee angle and moment data in the sagittal plane were incorporated into a previously developed model to estimate patellofemoral joint stress. The dependent variables of interest were the peak patellofemoral joint stress as well as the percentage of stance at which this peak occurred, as both the magnitude and the timing of the joint loading are thought to be important in overuse running injuries. The peak patellofemoral joint stress significantly increased in the orthotic condition by 5.8% (p=.02, ES=0.24), which does not support the initial hypothesis. However, the orthotic did significantly delay the timing of the peak during the stance phase by 3.8% (p=.002, ES=0.47). The finding that the peak patellofemoral joint stress increased in the orthotic condition did not support the initial hypothesis. However, the finding that the timing of this peak was delayed to later in the stance phase in the orthotic condition did support the initial hypothesis and may be related to the clinical improvements previously reported in subjects with PFP. Level 4.

  8. Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

    Science.gov (United States)

    Cumerlato, Marina; de Lima, Eduardo Martinelli; Osorio, Leandro Berni; Mota, Eduardo Gonçalves; de Menezes, Luciane Macedo; Rizzatto, Susana Maria Deon

    2017-01-01

    ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI. PMID:28902249

  9. Adapting without reinforcement.

    Science.gov (United States)

    Kheifets, Aaron; Gallistel, C Randy

    2012-11-01

    Our data rule out a broad class of behavioral models in which behavioral change is guided by differential reinforcement. To demonstrate this, we showed that the number of reinforcers missed before the subject shifted its behavior was not sufficient to drive behavioral change. What's more, many subjects shifted their behavior to a more optimal strategy even when they had not yet missed a single reinforcer. Naturally, differential reinforcement cannot be said to drive a process that shifts to accommodate to new conditions so adeptly that it doesn't miss a single reinforcer: it would have no input on which to base this shift.

  10. Caracterização mecânica de laminados cimentíceos esbeltos reforçados com fibras de sisal Mechanical characterization of cement-based thin-walled laminates reinforced with sisal fibre

    Directory of Open Access Journals (Sweden)

    Paulo R. L. Lima

    2007-12-01

    Full Text Available Com a proibição progressiva do uso de fibras de asbesto na fabricação de laminados à base de cimento, novos produtos têm sido desenvolvidos para suprir esta demanda do setor construtivo. A utilização de fibras de sisal como substituto ao asbesto, além de ser uma proposta ecológica tem grande importância socioeconômica, pois agregará valor a um produto cultivado com sucesso no semi-árido nordestino. Produziram-se, neste trabalho, placas laminadas com matriz de argamassa reforçadas com fibras longas de sisal. Ensaios de flexão em três pontos foram realizados com o objetivo de se estudar a influência da adição de fibras (3%, do número de camadas (2 e 3, da orientação das camadas (0 e 90° e da pressão de moldagem (0 e 2 MPa sobre o comportamento à flexão dos laminados. Os resultados indicam que a adição de fibras de sisal aumentou, para todos os casos estudados, a capacidade de absorver energia, a resistência à flexão pós-fissuração e a deflexão última do material. Os laminados reforçados com 3% de fibras de sisal, distribuídas em três camadas ortogonais à direção do carregamento e submetidos à pressão de moldagem de 2 MPa, apresentaram o melhor comportamento mecânico.Because of hazards to human and animal health, the use of asbestos and its products is being prohibited all around the world and academic institutions and fibre cement producers have been engaged in intensive research to find asbestos-free cement products. The application of natural fibres such as sisal to replace asbestos fibres can bring economical and ecological benefits due to their availability, low cost, low consumption of energy and suitability to the semi-arid area of the Northeast of Brazil (where not many plants can grow. In this paper, cement-based laminates reinforced with continuous sisal fibre were produced. Three point bending tests were carried out to evaluate the influence of addition of fibre (3%, number of layers of

  11. Design for whipping pipe impact on reinforced concrete panels

    International Nuclear Information System (INIS)

    Chen, C.C.; Gurbuz, O.

    1984-01-01

    This paper describes determination of local and overall effects on reinforced concrete panels due to whipping pipe impact in postulated pipe break events. Local damage includes the prediction of minimum concrete panel thickness required to prevent spalling from the back face of the target reinforced concrete panels. Evaluation of overall effect deals with the ductility ratio calculation for the target reinforced concrete panels. Design curves for determining the minimum panel thickness and the minimum reinforcement of reinforced concrete panels are presented in this paper for some cases commonly encountered in nuclear applications. The methodology and the results provided can be used to determine if an existing reinforced concrete wall is capable of resisting the whipping pipe impact, and consequently, if pipe whip restraints can be eliminated

  12. FRP strengthening of RC walls with openings

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Sas, Gabriel; Täljsten, Björn

    2009-01-01

    Strengthening reinforced concrete (RC) walls with openings using fibre reinforced polymers (FRP) has been experimentally proven to be a viable rehabilitation method. However, very few theoretical investigations are reported. In this paper two methods of analysis are presented. Since openings vary...... in size, the analysis of a strengthened wall can be divided into frame idealization method for large openings, and combined disk and frame analysis for smaller openings. The first method provides an easy to use tool in practical engineering, where the latter describes the principles of a ductile...

  13. Wall Turbulence.

    Science.gov (United States)

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  14. Genomic Signatures of Reinforcement

    Directory of Open Access Journals (Sweden)

    Austin G. Garner

    2018-04-01

    Full Text Available Reinforcement is the process by which selection against hybridization increases reproductive isolation between taxa. Much research has focused on demonstrating the existence of reinforcement, yet relatively little is known about the genetic basis of reinforcement or the evolutionary conditions under which reinforcement can occur. Inspired by reinforcement’s characteristic phenotypic pattern of reproductive trait divergence in sympatry but not in allopatry, we discuss whether reinforcement also leaves a distinct genomic pattern. First, we describe three patterns of genetic variation we expect as a consequence of reinforcement. Then, we discuss a set of alternative processes and complicating factors that may make the identification of reinforcement at the genomic level difficult. Finally, we consider how genomic analyses can be leveraged to inform if and to what extent reinforcement evolved in the face of gene flow between sympatric lineages and between allopatric and sympatric populations of the same lineage. Our major goals are to understand if genome scans for particular patterns of genetic variation could identify reinforcement, isolate the genetic basis of reinforcement, or infer the conditions under which reinforcement evolved.

  15. Genomic Signatures of Reinforcement

    Science.gov (United States)

    Goulet, Benjamin E.

    2018-01-01

    Reinforcement is the process by which selection against hybridization increases reproductive isolation between taxa. Much research has focused on demonstrating the existence of reinforcement, yet relatively little is known about the genetic basis of reinforcement or the evolutionary conditions under which reinforcement can occur. Inspired by reinforcement’s characteristic phenotypic pattern of reproductive trait divergence in sympatry but not in allopatry, we discuss whether reinforcement also leaves a distinct genomic pattern. First, we describe three patterns of genetic variation we expect as a consequence of reinforcement. Then, we discuss a set of alternative processes and complicating factors that may make the identification of reinforcement at the genomic level difficult. Finally, we consider how genomic analyses can be leveraged to inform if and to what extent reinforcement evolved in the face of gene flow between sympatric lineages and between allopatric and sympatric populations of the same lineage. Our major goals are to understand if genome scans for particular patterns of genetic variation could identify reinforcement, isolate the genetic basis of reinforcement, or infer the conditions under which reinforcement evolved. PMID:29614048

  16. Geosynthetic wall performance : facing pressure and deformation : final report.

    Science.gov (United States)

    2017-02-01

    The objective of the study was to validate the performance of blocked-faced Geosynthetic Reinforced Soil (GRS) wall and to validate the Colorado Department of Transportations (CDOT) decision to waive the positive block connection for closely-space...

  17. Habituation of reinforcer effectiveness

    Directory of Open Access Journals (Sweden)

    David R Lloyd

    2014-01-01

    Full Text Available In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE that links behavioral and neural based explanations of reinforcement. We argue that habituation of reinforcer effectiveness (HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009;Rankin et al., 2009. We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect ‘accelerated-HRE’. Consideration of HRE is important for the development of effective reinforcement based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior.

  18. Predictors of response to prefabricated foot orthoses or rocker-sole footwear in individuals with first metatarsophalangeal joint osteoarthritis.

    Science.gov (United States)

    Menz, Hylton B; Auhl, Maria; Tan, Jade M; Levinger, Pazit; Roddy, Edward; Munteanu, Shannon E

    2017-05-12

    Osteoarthritis of the first metatarsophalangeal joint (1st MTPJ OA) is a common and disabling condition commonly managed with footwear and orthotic interventions. The objective of this study was to identify factors associated with a successful treatment response in people with 1st MTPJ OA provided with prefabricated orthoses or rocker-sole footwear as part of a randomised clinical trial. People with 1st MTPJ OA (n = 88) who participated in a randomised trial were allocated to receive prefabricated foot orthoses (n = 47) or rocker-sole footwear (n = 41) and completed a baseline questionnaire including information on demographics, anthropometrics, general health, pain characteristics (including the Foot Health Status Questionnaire [FHSQ] and Foot Function Index [FFI]) and perceptions of the interventions, and a clinical assessment of foot posture, range of motion, radiographic severity and in-shoe plantar pressures. Adherence was documented using diaries. At 12 weeks, participants documented their perception of improvement on a 15-point scale. Those reporting at least moderate improvement on this scale were classified as 'responders'. There were 29 responders (62%) in the orthoses group and 16 responders (39%) in the rocker-sole group. In the orthoses group, responders had greater baseline pain severity while walking, a higher FFI difficulty score, and wore their orthoses more frequently. In the rocker-sole group, responders had a higher FFI stiffness score and greater radiographic severity. However, the accuracy of these variables in identifying responders in each group was modest (62 and 53%, respectively). The response to prefabricated orthoses or rocker-sole footwear in people with 1st MTPJ OA is related to measures of increased pain and disease severity. However, the overall classification accuracy associated with these factors is not sufficient for identifying individuals who are most likely to benefit from these interventions. Australian New

  19. Biomechanical Effects of Prefabricated Foot Orthoses and Rocker‐Sole Footwear in Individuals With First Metatarsophalangeal Joint Osteoarthritis

    Science.gov (United States)

    Auhl, Maria; Tan, Jade M.; Levinger, Pazit; Roddy, Edward; Munteanu, Shannon E.

    2016-01-01

    Objective To evaluate the effects of prefabricated foot orthoses and rocker‐sole footwear on spatiotemporal parameters, hip and knee kinematics, and plantar pressures in people with first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods. A total of 102 people with first MTP joint OA were randomly allocated to receive prefabricated foot orthoses or rocker‐sole footwear. The immediate biomechanical effects of the interventions (compared to usual footwear) were examined using a wearable sensor motion analysis system and an in‐shoe plantar pressure measurement system. Results Spatiotemporal/kinematic and plantar pressure data were available from 88 and 87 participants, respectively. The orthoses had minimal effect on spatiotemporal or kinematic parameters, while the rocker‐sole footwear resulted in reduced cadence, percentage of the gait cycle spent in stance phase, and sagittal plane hip range of motion. The orthoses increased peak pressure under the midfoot and lesser toes. Both interventions significantly reduced peak pressure under the first MTP joint, and the rocker‐sole shoes also reduced peak pressure under the second through fifth MTP joints and heel. When the effects of the orthoses and rocker‐sole shoes were directly compared, there was no difference in peak pressure under the hallux, first MTP joint, or heel; however, the rocker‐sole shoes exhibited lower peak pressure under the lesser toes, second through fifth MTP joints, and midfoot. Conclusion Prefabricated foot orthoses and rocker‐sole footwear are effective at reducing peak pressure under the first MTP joint in people with first MTP joint OA, but achieve this through different mechanisms. Further research is required to determine whether these biomechanical changes result in improvements in symptoms. PMID:26640157

  20. An Innovative Enhanced Wall to Reduce the Energy Demand in Buildings

    Science.gov (United States)

    Fantozzi, F.; Filipeschi, S.; Mameli, M.; Nesi, S.; Cillari, G.; Mantelli, M. B. H.; Milanez, F. H.

    2017-01-01

    Energy saving in buildings is one of most important issues for European countries. Although in the last years many studies have been carried out in order to reach the zero-consumption house the energy rate due to passive solar heating could be further enhanced. This paper proposes a method for increasing the energy rate absorbed by opaque walls by using a two phase loop thermosyphon connecting the internal and the external façade of a prefabricated house wall. The evaporator zone is embedded into the outside facade and the condenser is indoor placed to heat the domestic environment. The thermosyphon has been preliminary designed and implanted into a wall for a prefabricated house in Italy. An original dynamic thermal model of the building equipped with the thermosyphon wall allowed the evolution of the indoor temperature over time and the energy saving rates. The transient behaviour of the building has been simulated during the winter period by using the EnergyPlusTM software. The annual saving on the heating energy is higher than 50% in the case of a low consumption building.

  1. Habituation of reinforcer effectiveness.

    Science.gov (United States)

    Lloyd, David R; Medina, Douglas J; Hawk, Larry W; Fosco, Whitney D; Richards, Jerry B

    2014-01-09

    In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral- and neural-based explanations of reinforcement. We argue that HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009; Rankin etal., 2009). We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow) normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect "accelerated-HRE." Consideration of HRE is important for the development of effective reinforcement-based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior.

  2. Use of dry sludge from waste water treatment plants as an additive in prefabricated concrete brick

    Directory of Open Access Journals (Sweden)

    Yagüe, A.

    2002-09-01

    Full Text Available Dry sludge from the Sabadell Water Treatment Plant was used to prepare prefabricated concrete bricks. After characterising the sludge and the manufacturing process used to make the bricks, we define the conditions of addition of the sludges in the manufacture. Reference samples not containing sludge and samples containing 2 % of dry sludge by cement weight were prepared. The variation in density, porosity, absorption coefficient and compressive strength of the bricks with the presence of sludge was determined over time. Leaching of the bricks was determined according to the NEN 7345 standard. In most cases the addition of sludge produces a decrease in porosity and absorption coefficients and an increase in compressive strength, so one could expect these bricks to have greater durability. As regards leaching pollutants in the bricks, they are below the limit of the Dutch NEN standard for construction materials and thus can be classified as inert material.

    El estudio ha consistido en la utilización de lodo seco de origen biológico de la depuradora de aguas residuales de Sabadell (Riu Sec, como adición en la preparación de adoquines de hormigón prefabricado. Después de caracterizar los lodos y el proceso de fabricación de los adoquines que utilizaremos, definimos las condiciones de adición de los lodos en esta fabricación. Se prepararon muestras de referencia, sin adición, y muestras con el 2 % de lodo seco sobrepeso de cemento. Se determinaron cómo variaban en el tiempo, con la presencia de lodos: la densidad, la porosidad y el coeficiente de absorción, y la resistencia mecánica a compresión de los adoquines. También se determinó la lixiviación que estas piezas presentaban de acuerdo a la norma NEN 7345. La adición de lodos produce, en la mayoría de los casos, una disminución de las porosidades y de los coeficientes de absorción y un aumento en las resistencias mecánicas, por lo que cabe esperar una mayor

  3. Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment

    Directory of Open Access Journals (Sweden)

    Rudys Rodolfo de Jesus Tavarez

    2011-02-01

    Full Text Available OBJECTIVES: The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. MATERIAL AND METHODS: Standard metal crowns were fabricated for 5 groups (n=10 of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricated abutment; Group 4, external hexagon implant and UCLA cast-on premachined abutment; and Group 5, external hexagon implant and Ceraone abutment. For groups 1, 2, 3 and 5, the crowns were cemented on the abutments and in group 4 crowns were screwed directly on the implant. The specimens were subjected to 500,000 cycles at 19.1 Hz of frequency and non-axial load of 133 N in a MTS 810 machine. The vertical misfit (μm at the implant/abutment interface was evaluated before (B and after (A application of the cyclic loading. Data were analyzed statistically by using two-away ANOVA and Tukey's post-hoc test (p<0.05. RESULTS: Before loading values showed no difference among groups 2 (4.33±3.13, 3 (4.79±3.43 and 5 (3.86±4.60; between groups 1 (12.88±6.43 and 4 (9.67±3.08, and among groups 2, 3 and 4. However, groups 1 and 4 were significantly different from groups 2, 3 and 5. After loading values of groups 1 (17.28±8.77 and 4 (17.78±10.99 were significantly different from those of groups 2 (4.83±4.50, 3 (8.07±4.31 and 5 (3.81±4.84. There was a significant increase in misfit values of groups 1, 3 and 4 after cyclic loading, but not for groups 2 and 5. CONCLUSIONS: The cyclic loading and type of implant/abutment connection may develop a role on the vertical misfit at the implant/abutment interface.

  4. Large Prefabricated Concrete Panels Collective Dwellings from the 1970s: Context and Improvements

    Science.gov (United States)

    Muntean, Daniel M.; Ungureanu, Viorel; Petran, Ioan; Georgescu, Mircea

    2017-10-01

    The period between 1960s and 1970s had a significant impact in Romania on the urban development of major cities. Because the vast expansion of the industry, the urban population has massively increased, due the large number of workers coming from the rural areas. This intense process has led to a shortage of homes on the housing market. In order to rapidly build new homes, standard residential project types were erected using large prefabricated concrete panels. By using repetitive patterns, such buildings were built in a short amount of time through the entire country. Nowadays, these buildings represent 1.8% of the built environment and accommodate more than half of a city’s population. Even though these units have reached only half their intended life span, they fail to satisfy present living standards and consume huge amounts of energy for heating, cooling, ventilation and lighting. Due to the fact that these building are based on standardised projects and were built in such a large scale, the creation of a system that brings them to current standards will not only benefit the building but also it will significantly improve the quality of life within. With the transition of the existing power grids to a “smart grid” such units can become micro power plants in future electricity networks thus contributing to micro-generation and energy storage. If one is to consider the EU 20-20-20 commitments, to find ideas for alternative and innovative strategies for further improving these building through locally adapted measures can be seen as one of the most addressed issues of today. This research offers a possible retrofitting scenario of these buildings towards a sustainable future. The building envelope is upgraded using a modular insulation system with integrated solar cells. Renewable energy systems for cooling and ventilation are integrated in order to provide flexibility of the indoor climate. Due to their small floor area, the space within the apartments is

  5. Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

    Science.gov (United States)

    2016-01-01

    Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-apically. In the control group, horizontal external mattress sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 1 and 3 months. Results Healing was uneventful in both groups. The difference of width between baseline and 1 month was −0.26±0.85 mm in the test group, without any statistical significance (P=0.137). Meanwhile, the corresponding difference in the control group was −0.74±0.73 mm and it showed statistical significance (Pprefabricated implant-retained stent was shown to be effective in the preservation of the keratinized mucosa around implants and it was simple and straightforward in comparison to the horizontal external mattress suture technique. PMID:27800215

  6. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defence signals, such as salicylic acid and 12-oxo-phytodienoic acid, but not jasmonic acid, upon Botrytis cinerea infection.

    Science.gov (United States)

    Ponce De León, Inés; Schmelz, Eric A; Gaggero, Carina; Castro, Alexandra; Álvarez, Alfonso; Montesano, Marcos

    2012-10-01

    The moss Physcomitrella patens is an evolutionarily basal model system suitable for the analysis of plant defence responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea, several defence mechanisms are induced in P. patens, including the fortification of the plant cell wall by the incorporation of phenolic compounds and the induced expression of related genes. Botrytis cinerea infection also activates the accumulation of reactive oxygen species and cell death with hallmarks of programmed cell death in moss tissues. Salicylic acid (SA) levels also increase after fungal infection, and treatment with SA enhances transcript accumulation of the defence gene phenylalanine ammonia-lyase (PAL) in P. patens colonies. The expression levels of the genes involved in 12-oxo-phytodienoic acid (OPDA) synthesis, including lipoxygenase (LOX) and allene oxide synthase (AOS), increase in P. patens gametophytes after pathogen assault, together with a rise in free linolenic acid and OPDA concentrations. However, jasmonic acid (JA) could not be detected in healthy or infected tissues of this plant. Our results suggest that, although conserved defence signals, such as SA and OPDA, are synthesized and are probably involved in the defence response of P. patens against B. cinerea infection, JA production appears to be missing. Interestingly, P. patens responds to OPDA and methyl jasmonate by reducing moss colony growth and rhizoid length, suggesting that jasmonate perception is present in mosses. Thus, P. patens can provide clues with regard to the evolution of different defence pathways in plants, including signalling and perception of OPDA and jasmonates in nonflowering and flowering plants. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

  7. A study of the bending resistance of implant-supported reinforced alumina and machined zirconia abutments and copies.

    Science.gov (United States)

    Sundh, Anders; Sjögren, Göran

    2008-05-01

    The purpose of the present study was to evaluate the bending resistance of implant-supported CAD/CAM-processed restorations made out of zirconia or manually shaped made out of reinforced alumina. Units of abutments and copies made of (i) a prefabricated hot isostatic pressed (HIPed) yttrium oxide partially-stabilized zirconia (Y-TZP) (Denzir), (ii) a prefabricated densely-sintered magnesia partially stabilized zirconia (Mg-PSZ) (Denzir-M) or, copies made of (iii) a prefabricated partially-sintered, porous reinforced alumina ceramic (RN synOcta-In-Ceram) were subjected to static loading perpendicularly at the long axis. The abutments were attached to either stainless steel analogs or titanium implant fixtures. The Y-TZP and Mg-PSZ copies were bonded onto the ceramic abutments with a dual-cured resin composite (Rely-X Unicem). Units of titanium abutment attached to a titanium implant fixtures were used as reference. The units comprising Denzir abutments as delivered (pstainless steel analogs exhibited significantly higher bending resistance than the control. The heat-treated Denzir copies bonded to the heat-treated Denzir M abutments attached to titanium implant fixtures and the In-Ceram specimens attached to stainless steel analogs showed significantly (pstainless steel analogs. No statistically significant (p>0.05) differences were seen among the other groups studied. All the ceramic abutments and copies exhibited values that were equal or superior to that of the control and exceeded the reported value, up to 300 N, for maximum incisal bite forces. To assess the clinical behavior long-term clinical studies should be conducted.

  8. Tension tests of concrete containment wall elements

    International Nuclear Information System (INIS)

    Schultz, D.M.; Julien, J.T.; Russel, H.G.

    1984-01-01

    Tension tests of concrete containment wall elements were conducted as part of a three-phase research program sponsored by the Electric Power Research Institute (EPRI). The objective of the EPRI experimental/analytical program is twofold. The first objective is to provide the utility industry with a test-verified analytical method for making realistic estimates of actual capacities of reinforced and prestressed concrete containments under internal over-pressurization from postulated degraded core accidents. The second objective is to determine qualitative and quantitative leak rate characteristics of typical containment cross-sections with and without penetrations. This paper covers the experimental portion to the EPRI program. The testing program for Phase 1 included eight large-scale specimens representing elements from the wall of a containment. Each specimen was 60-in (1525-mm) square, 24-in (610-mm) thick, and had full-size reinforcing bars. Six specimens were representative of prototypical reinforced concrete containment designs. The remaining two specimens represented prototypical prestressed containment designs. Various reinforcement configurations and loading arrangements resulted in data that permit comparisons of the effects of controlled variables on cracking and subsequent concrete/reinforcement/liner interaction in containment elements. Subtle differences, due to variations in reinforcement patterns and load applications among the eight specimens, are being used to benchmark the codes being developed in the analytical portion of the EPRI program. Phases 2 and 3 of the test program will examine leak rate characteristics and failure mechanisms at penetrations and structural discontinuities. (orig.)

  9. Seismic fragility of reinforced concrete structures in nuclear facilities

    International Nuclear Information System (INIS)

    Gergely, P.

    1985-01-01

    The failure and fragility analyses of reinforced concrete structures and elements in nuclear reactor facilities within the Seismic Safety Margins Research Program (SSMRP) at the Lawrence Livermore National Laboratory are evaluated. Uncertainties in material modeling, behavior of low shear walls, and seismic risk assessment for nonlinear response receive special attention. Problems with ductility-based spectral deamplification and prediction of the stiffness of reinforced concrete walls at low stress levels are examined. It is recommended to use relatively low damping values in connection with ductility-based response reductions. The study of static nonlinear force-deflection curves is advocated for better nonlinear dynamic response predictions

  10. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...

  11. Structural behavior of reinforced concrete structures at high temperatures

    International Nuclear Information System (INIS)

    Yamazaki, N.; Yamazaki, M.; Mochida, T.; Mutoh, A.; Miyashita, T.; Ueda, M.; Hasegawa, T.; Sugiyama, K.; Hirakawa, K.; Kikuchi, R.; Hiramoto, M.; Saito, K.

    1995-01-01

    To establish a method to predict the behavior of reinforced concrete structures subjected simultaneously to high temperatures and external loads, this paper presents the results obtained in several series of tests carried out recently in Japan. This paper reports on the material properties of concrete and steel bars under high temperatures. It also considers the heat transfer properties of thick concrete walls under transient high temperatures, and the structural behavior of reinforced concrete beams subjected to high temperatures. In the tests, data up to 800 C were obtained for use in developing a computational method to estimate the non-linear behavior of reinforced concrete structures exposed to high temperatures. (orig.)

  12. Use of flexible facing for soil nail walls.

    Science.gov (United States)

    2011-11-01

    Soil nail walls are a widely used technology for retaining vertical and nearly vertical cuts in soil. A : significant portion of the cost of soil nail wall construction is related to the construction of a reinforced : concrete face. The potential for...

  13. Towards a more common use of Ultra-High Performance Concrete (UHPC) – development of UHPC for ready-mix and prefabrication concrete plants

    NARCIS (Netherlands)

    Spiesz, P.R.; Hunger, M.; Justnes, Harald; Braarud, Henny

    2017-01-01

    This study addresses the development of ultra-high performance concrete (UHPC) suitable for a mass production in conventional ready-mix and prefabrication concrete plants. In order to facilitate the production process, curing regime and to minimize the costs, no additional treatments (e.g. thermal

  14. Modelling the behaviour of steel fibre reinforced precast beam-to-column connection

    Science.gov (United States)

    Chai, C. E.; Sarbini, NN; Ibrahim, I. S.; Ma, C. K.; Tajol Anuar, M. Z.

    2017-11-01

    The numerical behaviour of steel fibre reinforced concrete (SFRC) corbels reinforced with different fibre volume ratio subjected to vertical incremental load is presented in this paper. Precast concrete structures had become popular in the construction field, which offer a faster, neater, safer, easier and cheaper construction work. The construction components are prefabricated in controlled environment under strict supervision before being erected on site. However, precast beam-column connections are prone to failure due to the brittle properties of concrete. Finite element analysis (FEA) is adopted due to the nonlinear behaviour of concrete and SFRC. The key objective of this research is to develop a reliable nonlinear FEA model to represent the behaviour of reinforced concrete corbel. The developed model is validated with experimental data from previous researches. Then, the validated FEA model is used to predict the behaviour of SFRC corbel reinforced with different fibre volume ratio by changing the material parameters. The results show that the addition of steel fibre (SF) increases the load carrying capacity, ductility, stiffness, and changed the failure mode of corbel from brittle bending-shear to flexural ductile. On the other hand, the increasing of SF volume ratio also leads to increased load carrying capacity, ductility, and stiffness of corbel.

  15. Modeling of shear wall buildings

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A K [North Carolina State Univ., Raleigh (USA). Dept. of Civil Engineering

    1984-05-01

    Many nuclear power plant buildings, for example, the auxiliary building, have reinforced concrete shear walls as the primary lateral load resisting system. Typically, these walls have low height to length ratio, often less than unity. Such walls exhibit marked shear lag phenomenon which would affect their bending stiffness and the overall stress distribution in the building. The deformation and the stress distribution in walls have been studied which is applicable to both the short and the tall buildings. The behavior of the wall is divided into two parts: the symmetric flange action and the antisymmetry web action. The latter has two parts: the web shear and the web bending. Appropriate stiffness equations have been derived for all the three actions. These actions can be synthesized to solve any nonlinear cross-section. Two specific problems, that of lateral and torsional loadings of a rectangular box, have been studied. It is found that in short buildings shear lag plays a very important role. Any beam type formulation which either ignores shear lag or includes it in an idealized form is likely to lead to erroneous results. On the other hand a rigidity type approach with some modifications to the standard procedures would yield nearly accurate answers.

  16. Diaphragm walling for Sizewell B sets records

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The first phase of construction of the Sizewell-B nuclear reactor has been completed. This was the building of a diaphragm wall around the site. It is one of the largest and deepest diaphragm walls to be installed in Europe. The site can be pumped dry of groundwater and the foundations constructed in the dry. The specifications of the wall and its construction, using two Hydrofraise excavation rigs, are described. The excavated material is brought up as a slurry and the (bentonite) slurry is cleaned and desanded. Most of the wall has been formed using a plastic concrete but reinforced concrete has been used for some stretches. The diaphragm wall, which is 1258m long and 55m deep on average, was built in 19 weeks. (U.K.)

  17. Algorithms for Reinforcement Learning

    CERN Document Server

    Szepesvari, Csaba

    2010-01-01

    Reinforcement learning is a learning paradigm concerned with learning to control a system so as to maximize a numerical performance measure that expresses a long-term objective. What distinguishes reinforcement learning from supervised learning is that only partial feedback is given to the learner about the learner's predictions. Further, the predictions may have long term effects through influencing the future state of the controlled system. Thus, time plays a special role. The goal in reinforcement learning is to develop efficient learning algorithms, as well as to understand the algorithms'

  18. Photoelastic stress analysis of different prefabricated post-and-core materials.

    Science.gov (United States)

    Asvanund, Pattapon; Morgano, Steven M

    2011-01-01

    The purpose of this study was to investigate stress developed by a combination of a stainless steel post or a fiber-reinforced resin post with a silver amalgam core or a composite resin core. Two-dimensional photoelastic models were used to simulate root dentin. Posts (ParaPost XT and ParaPost-FiberWhite) were cemented with a luting agent (RelyX Unicem). Silver amalgam cores and composite resin cores were fabricated on the posts. Complete crowns were fabricated and cemented on the cores. Each model was analyzed with 2 force magnitudes and in 2 directions. Fringe orders were recorded and compared using ANOVA (p=0.05) and the Scheffe's test. With vertical force, no stress differences occurred among the 4 groups (p=0.159). With a 30-degree force, there was stress differences among the 4 groups (p<0.001). The combination of a fiber-reinforced post and composite resin core could potentially reduce stresses within the radicular dentin when angled loads are applied.

  19. Static in-plane shear behaviour of prefabricated wood-wool panel wallettes

    Science.gov (United States)

    Noh, M. S. Md; Ahmad, Z.; Ibrahim, A.; Kamarudin, A. F.; Mokhatar, S. N.

    2018-04-01

    The green construction material and technique are the current issue toward improving sustainability in the construction industry in Malaysia. The use of construction material that produced from renewable resources is a part of the effort for greening this industry. WWCP (Wood-wool cement panel) is a wood based product available to the construction industry to be used as a structural building wall element. This renewable material has the potential to replace the less eco-friendly materials such as bricks and other masonry element. However, the behaviour of wall subjected to the different load conditions is not well established and therefore, this study aimed to investigate the structural behaviour of the small scale wall (wallettes) subjected to in-plane lateral load. As a comparison, two types of fabrication technique of wallettes with dimension of 1200 mm × 1200 mm (± 30 mm) were considered. The conventional vertical stacking technique was denoted as W1 and new propose techniques (cross laminated) was denoted as W2. Three replicates of each type were fabricated and tested under in-plane lateral load until failure. The test results revealed that, the wallettes fabricated using the new fabrication technique significantly increased two times in load carrying capacity compared to wallettes with conventional technique.

  20. Damping characteristics of reinforced concrete structures

    International Nuclear Information System (INIS)

    Hisano, M.; Nagashima, I.; Kawamura, S.

    1987-01-01

    Reinforced concrete structures in a nuclear power plant are not permitted to go far into the inelasticity generally, even when subjected to strong ground motion. Therefore it is important to evaluate the damping appropriately in linear and after cracking stage before yielding in the dynamic response analysis. Next three dampings are considered of reinforced concrete structures. 1) Internal damping in linear range material damping of concrete without cracks;2) Hysteretic damping in inelastic range material hysteretic damping of concrete due to cracking and yielding;3) Damping due to the energy dissipation into the ground. Among these damping material damping affects dynamic response of a nuclear power plant on hard rock site where damping due to energy dissipation into the ground is scarcely expected. However material damping in linear and slightly nonlinear range have only been assumed without enough experimental data. In this paper such damping is investigated experimentally by the shaking table tests of reinforced concrete box-walls which modeled roughly the outer wall structure of a P.W.R. type nuclear power plant

  1. Modeling reinforced concrete durability.

    Science.gov (United States)

    2014-06-01

    This project developed a next-generation modeling approach for projecting the extent of : reinforced concrete corrosion-related damage, customized for new and existing Florida Department of : Transportation bridges and suitable for adapting to broade...

  2. LABORATORY EVALUATION ON PERFORMANCE OF GLASS FIBER REINFORCED PLASTIC MORTAR PIPE CULVERTS

    Directory of Open Access Journals (Sweden)

    Huawang Shi

    2018-04-01

    Full Text Available This paper investigated the performance and behaviour of glass fiber reinforced plastic mortar (FRPM pipes under different loading conditions. FRPM pipes with inner diameter of 1500 mm were prefabricated in factory. Mechanics performance testing (ring and axial compressive strength and elastic modulus, stiffness and fatigue test were carried out in laboratory. Ring stiffness test provided pipe stiffness (PS which is a function of geometry and material type of pipe through parallel plate loading test (PPLT. The fatigue test and micro-structure measure method were used to evaluate the durability effects of FRPM under repeated compression load. Results indicated that FRPM pipes had better mechanic performances as the road culverts under soils. It may be helpful for the design and construction of FRPM culverts.

  3. Corrosion resistance of steel fibre reinforced concrete – a literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2016-01-01

    Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding...... the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing...... the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated...

  4. Experimental study of a shear wall with numerous small openings

    International Nuclear Information System (INIS)

    Sotomura, K.; Murazumi, Y.; Yoshizaki, S.; Ezaki, T.

    1981-01-01

    Many small openings for piping and ducts are usually required in the shear walls for PWR nuclear power plant. It is generally believed that such openings oadversely affect the strength and stiffness of shear walls. However, little information is available concerning the behavior of walls with numerous small openings. Therefore, tests using wall specimens and an analysis using an FEM program were carried out to investigate this behavior. Main findings are as follows: 1) The ultimate strength of a shear wall with numerous small openings may be obtained by using the effective area at the critical cross section of the shear wall. 2) Shear walls with openings can be restored to the same shear strength and stiffness as shear walls without openings by diagonal reinforcement. (orig./HP)

  5. Interaction between drilled shaft and mechanically stabilized earth (MSE) wall : project summary.

    Science.gov (United States)

    2015-08-31

    Drilled shafts are being constructed within the reinforced zone of mechanically stabilized earth (MSE) walls (Figure 1). The drilled shafts may be subjected to horizontal loads and push against the front of the wall. Distress of MSE wall panels has b...

  6. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-05

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Shear wall ultimate drift limits

    International Nuclear Information System (INIS)

    Duffey, T.A.; Goldman, A.; Farrar, C.R.

    1994-04-01

    Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated

  8. Possibilities of free cooling in prefabricated residential buildings; Moeglichkeiten der freien Kuehlung fuer Wohngebaeude in Fertigbauweise

    Energy Technology Data Exchange (ETDEWEB)

    Truemper, H.; Hain, K.; Wirth, S. [Dortmund Univ. (Germany). Lehrstuhl Technische Gebaeudeausruestung

    1999-07-01

    Due to their efficient heat insulation, modern low-energy houses can develop disagreeably high room temperatures in the summer. Use of room cooling devices for cooling residential buildings in central Europe is not feasible for ecological as well as economic reasons. This paper presents the buried heat exchanger and the cellar wall exchanger as alternatives to the cooling of incoming air in ventilated low-energy residential buildings. Both are in principle cold storages with coiled pipes taking in air from outside. The buried heat exchanger is charged with cold during the heating period (seasonal storage), whereas the cellar wall exchanger accumulates and gives off cold daily. (orig.) [German] In modernen Niedrigenergiehaeusern koennen sich aufgrund einer verbesserten Waermedaemmung waehrend des Sommers Raumtemperaturen einstellen, die nicht als behaglich empfunden werden. Raumkuehlgeraete scheiden aus oekologischen und oekonomischen Gruenden fuer eine Kuehlung von Wohngebaeuden in Mitteleuropa aus. Als Alternativen zur Kuehlung der Zuluft bei Niedrigenergiehaeusern mit Wohnungslueftung werden der Erdwaermeaustauscher und der Kellerwandaustauscher vorgestellt. Hierbei handelt es sich um Kaeltespeicher, in welchen Rohrschlangen verlegt sind, ueber welche die Aussenluft angesaugt wird. Der Erdwaermeaustauscher wird als Kaeltespeicher waehrend der Heizperiode aufgeladen (saisonaler Speicher), wohingegen der Kellerwandaustauscher taeglich be- und entladen wird. (orig.)

  9. Behavior of reinforced concrete beams reinforced with GFRP bars

    Directory of Open Access Journals (Sweden)

    D. H. Tavares

    Full Text Available The use of fiber reinforced polymer (FRP bars is one of the alternatives presented in recent studies to prevent the drawbacks related to the steel reinforcement in specific reinforced concrete members. In this work, six reinforced concrete beams were submitted to four point bending tests. One beam was reinforced with CA-50 steel bars and five with glass fiber reinforced polymer (GFRP bars. The tests were carried out in the Department of Structural Engineering in São Carlos Engineering School, São Paulo University. The objective of the test program was to compare strength, reinforcement deformation, displacement, and some anchorage aspects between the GFRP-reinforced concrete beams and the steel-reinforced concrete beam. The results show that, even though four GFRP-reinforced concrete beams were designed with the same internal tension force as that with steel reinforcement, their capacity was lower than that of the steel-reinforced beam. The results also show that similar flexural capacity can be achieved for the steel- and for the GFRP-reinforced concrete beams by controlling the stiffness (reinforcement modulus of elasticity multiplied by the bar cross-sectional area - EA and the tension force of the GFRP bars.

  10. DEGREDATION PROPERTIES OF REINFORCED CONCRETE WALLS WITH OPENINGS

    Directory of Open Access Journals (Sweden)

    JULIAN CARRILLO

    2011-01-01

    Full Text Available En este artículo se compara el comportamiento de cuatro muros aislados de concreto reforzado (CR con aberturas: dos muros prototipo ensayados bajo carga cuasi-estática cíclica (CEC y dos muros ensayados bajo excitación de mesa vibratoria. Las variables estudiadas fueron la cuantía de acero en el alma, el tipo de acero de refuerzo en el alma y el método de ensaye. A partir de la respuesta medida se verificó que la historia de carga de los ensayos CEC ignora los efectos dinámicos fundamentales observados en estructuras sometidas a cargas sísmicas. Cuando las respuestas dinámicas y CEC cíclicas se compararon, se observó que las propiedades de degradación de rigidez y resistencia dependen de la velocidad de aplicación de carga, los mecanismos de resistencia asociados a los modos de falla, el número de ciclos y los parámetros acumulados de la demanda de ductilidad y energía disipada. Por lo tanto, los datos obtenidos a partir de ensayos CEC no siempre se pueden suponer de forma segura como un límite inferior de la capacidad esperada. En el artículo también se proponen modelos de degradación de rigidez y resistencia para muros de CR con aberturas sometidos a carga del tipo sísmica.

  11. Steel fiber reinforced concrete

    International Nuclear Information System (INIS)

    Baloch, S.U.

    2005-01-01

    Steel-Fiber Reinforced Concrete is constructed by adding short fibers of small cross-sectional size .to the fresh concrete. These fibers reinforce the concrete in all directions, as they are randomly oriented. The improved mechanical properties of concrete include ductility, impact-resistance, compressive, tensile and flexural strength and abrasion-resistance. These uniqlte properties of the fiber- reinforcement can be exploited to great advantage in concrete structural members containing both conventional bar-reinforcement and steel fibers. The improvements in mechanical properties of cementitious materials resulting from steel-fiber reinforcement depend on the type, geometry, volume fraction and material-properties of fibers, the matrix mix proportions and the fiber-matrix interfacial bond characteristics. Effects of steel fibers on the mechanical properties of concrete have been investigated in this paper through a comprehensive testing-programme, by varying the fiber volume fraction and the aspect-ratio (Lid) of fibers. Significant improvements are observed in compressive, tensile, flexural strength and impact-resistance of concrete, accompanied by marked improvement in ductility. optimum fiber-volume fraction and aspect-ratio of steel fibers is identified. Test results are analyzed in details and relevant conclusions drawn. The research is finally concluded with future research needs. (author)

  12. Reinforced flexural elements for TEMP-STRESS Program

    International Nuclear Information System (INIS)

    Marchertas, A.H.; Kennedy, J.M.; Pfeiffer, P.A.

    1987-06-01

    The implementation of reinforced flexural elements into the thermal-mechanical finite element program TEMP-STRESS is described. With explicit temporal integration and dynamic relaxation capabilities in the program, the flexural elements provide an efficient method for the treatment of reinforced structures subjected to transient and static loads. The capability of the computer program is illustrated by the solution of several examples: the simulation of a reinforced concrete beam; simulations of a reinforced concrete containment shell which is subjected to internal pressurization, thermal gradients through the walls, and transient pressure loads. The results of this analysis are relevant in the structural design/safety evaluations of typical reactor containment structures. 22 refs., 13 figs

  13. Seismic Performance of Precast Polystyrene RC Walls

    Directory of Open Access Journals (Sweden)

    Wibowo Ari

    2017-01-01

    Full Text Available Precast concrete structure such as precast wall is a concept that is growing rapidly these days. However, the earthquake resistance is believed to be one of its drawbacks. Additionally, the large weight of solid elements also increase the building weight significantly which consequently increase the earthquake base shear force as well. Therefore, investigation on the seismic performance of precast concrete wall has been carried out. Three RC wall specimens using wire mesh reinforcement and EPS (Extended Polystyrene System panel have been tested. This wall was designed as a structural wall that was capable in sustaining lateral loads (in-plane yet were lightweight to reduce the total weight of the building. Parameter observed was the ratio of height to width (aspect ratio of wall of 1.0, 1.5 and 2.0 respectively with the aim to study the behaviour of brittle to ductile transition of the wall. Incremental static load tests were conducted until reaching peak load and then followed by displacement control until failure. Several data were measured at every stage of loading comprising lateral load-displacement behaviour, ultimate strength and collapse mechanism. The outcomes showed that precast concrete walls with a steel wire and EPS panel filler provided considerably good resistance against lateral load.

  14. 221-U Facility concrete and reinforcing steel evaluations specification for the canyon disposition initiative (CDI)

    International Nuclear Information System (INIS)

    Baxter, J.T.

    1998-01-01

    This describes a test program to establish the in-situ material properties of the reinforced concrete in Building 221-U for comparison to the original design specifications. Field sampling and laboratory testing of concrete and reinforcing steel structural materials in Building 221-U for design verification will be undertaken. Forty seven samples are to be taken from radiologically clean exterior walls of the canyon. Laboratory testing program includes unconfined compressive strength of concrete cores, tensile strength of reinforcing steel, and petrographic examinations of concrete cores taken from walls below existing grade

  15. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    Directory of Open Access Journals (Sweden)

    Wenbin SUN

    2014-12-01

    Full Text Available Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete-filled FRP tube (CFFT short columns and three plain concrete control specimens were tested. All specimens were axially loaded until failure. The rest results showed that the stress-strain curves of CFFTs consisted of two distinct branches, an ascending branch before the concrete peak stress was reaches and a second branch that terminated when the tube ruptured, and that the CFFTs with integrated crossties experienced most uniform confinement pressure distribution. Test research also found that the stress-strain curves of CFFTs indicated an increase in ductility. These demonstrate that this confinement system can produce higher lateral confinement stiffness. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6035

  16. Reinforced concrete tomography

    International Nuclear Information System (INIS)

    Mariscotti, M.A.J.; Morixe, M.; Tarela, P.A.; Thieberger, P.

    1997-01-01

    In this paper we describe the technique of reinforced concrete tomography, its historical background, recent technological developments and main applications. Gamma radiation sensitive plates are imprinted with radiation going through the concrete sample under study, and then processed to reveal the presence of reinforcement and defects in the material density. The three dimensional reconstruction, or tomography, of the reinforcement out of a single gammagraphy is an original development alternative to conventional methods. Re-bar diameters and positions may be determined with an accuracy of ± 1 mm 0.5-1 cm, respectively. The non-destructive character of this technique makes it particularly attractive in cases of inhabited buildings and diagnoses of balconies. (author) [es

  17. First wall

    International Nuclear Information System (INIS)

    Omori, Junji.

    1991-01-01

    Graphite and C/C composite are used recently for the first wall of a thermonuclear device since materials with small atom number have great impurity allowable capacity for plasmas. Among them, those materials having high thermal conduction are generally anisotropic and have an upper limit for the thickness upon production. Then, anisotropic materials are used for a heat receiving plate, such that the surfaces of the heat receiving plate on the side of lower heat conductivity are brought into contact with each other, and the side of higher thermal conductivity is arranged in parallel with small radius direction and the toroidal direction of the thermonuclear device. As a result, the incident heat on an edge portion can be transferred rapidly to the heat receiving plate, which can suppress the temperature elevation at the surface to thereby reduce the amount of abrasion. Since the heat expansion coefficient of the anisotropic materials is great in the direction of the lower heat conductivity and small in the direction of the higher heat conductivity, the gradient of a thermal load distribution in the direction of the higher heat expansion coefficient is small, and occurrence of thermal stresses due to temperature difference is reduced, to improve the reliability. (N.H.)

  18. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  19. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-11-01

    Full Text Available In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS, electron probe microanalysis (EPMA, scanning electron microscope (SEM and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ~38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as (Cr, W, Fe23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA (69.5 HRC is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

  20. Braided reinforced composite rods for the internal reinforcement of concrete

    Science.gov (United States)

    Gonilho Pereira, C.; Fangueiro, R.; Jalali, S.; Araujo, M.; Marques, P.

    2008-05-01

    This paper reports on the development of braided reinforced composite rods as a substitute for the steel reinforcement in concrete. The research work aims at understanding the mechanical behaviour of core-reinforced braided fabrics and braided reinforced composite rods, namely concerning the influence of the braiding angle, the type of core reinforcement fibre, and preloading and postloading conditions. The core-reinforced braided fabrics were made from polyester fibres for producing braided structures, and E-glass, carbon, HT polyethylene, and sisal fibres were used for the core reinforcement. The braided reinforced composite rods were obtained by impregnating the core-reinforced braided fabric with a vinyl ester resin. The preloading of the core-reinforced braided fabrics and the postloading of the braided reinforced composite rods were performed in three and two stages, respectively. The results of tensile tests carried out on different samples of core-reinforced braided fabrics are presented and discussed. The tensile and bending properties of the braided reinforced composite rods have been evaluated, and the results obtained are presented, discussed, and compared with those of conventional materials, such as steel.

  1. Soil reinforcement with geosynthetics

    Directory of Open Access Journals (Sweden)

    Bessaim Mohammed Mustapha

    2018-01-01

    Full Text Available The proportionality of existence of land with good bearing to erect any building or building is very small, to remedy this deficiency it is necessary to resort to techniques of reinforcement of the soils which can constitute a very important development. Among these methods of remediation, there is reinforcement by the geosynthetics which constitute an effective solution to these constraints. This process tends to stabilize the soil in question with increased load bearing capacity in civil engineering and geotechnical works such as embankments, slopes, embankments and hydraulic structures, with an inestimable gain in time, economy and durability while preserving the natural and environmental aspect.

  2. Preliminary Study on Impact Resistances of Fiber Reinforced Concrete Applied Nuclear Power Plants

    International Nuclear Information System (INIS)

    Jin, Byeong Moo; Kim, Young Jin; Jeon, Se Jin

    2013-01-01

    Studies to improve the impact resistance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application ratio, are in progress. Authors assessed first the impact resistance of concrete walls depending upon fiber types and missile impact velocities. The safety assessment of nuclear power plants against large civil aircraft crashes have been accomplished for normal concrete and fiber reinforced concretes in this study. Studies on the safety assessments on the nuclear power plants against large civil aircraft crashes are ongoing actively. As a step of evaluating the applicability of fiber reinforced concrete in means of ensuring more structural safety of the nuclear power plants against impact, the impact resistance for the 1% steel and 2% polyamide fiber reinforced concretes have been evaluated. For reactor containment building structures, it seem there is no impact resistance enhancement of fiber reinforced concrete applied to reactor containment building in the cases of impact velocity 150 m/sec considered in this study. However this results from the pre-stressing forces which introduce compressive stresses in concrete wall and dome section of reactor containment building. Nonetheless there may be benefits to apply fiber reinforced concrete to nuclear power plants. For double containment type reactor containment building, the outer structure is a reinforced concrete structure. The impact resistances for non pre-stressed cylindrical reactor containment buildings are enhanced by 23 to 47 % for 2 % polyamide fiber reinforced concretes and 1 % steel fiber reinforced concretes respectively. For other buildings such as auxiliary building, compound building and fuel storage building surrounding the reactor containment building, there are so many reinforced concrete walls which are anticipated some enhancements of impact resistance by using fiber reinforced concretes. And heavier or faster large civil aircraft impacts produce higher

  3. Preliminary Study on Impact Resistances of Fiber Reinforced Concrete Applied Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Byeong Moo; Kim, Young Jin; Jeon, Se Jin [Daewoo E and C Co. Ltd., Suwon (Korea, Republic of)

    2013-10-15

    Studies to improve the impact resistance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application ratio, are in progress. Authors assessed first the impact resistance of concrete walls depending upon fiber types and missile impact velocities. The safety assessment of nuclear power plants against large civil aircraft crashes have been accomplished for normal concrete and fiber reinforced concretes in this study. Studies on the safety assessments on the nuclear power plants against large civil aircraft crashes are ongoing actively. As a step of evaluating the applicability of fiber reinforced concrete in means of ensuring more structural safety of the nuclear power plants against impact, the impact resistance for the 1% steel and 2% polyamide fiber reinforced concretes have been evaluated. For reactor containment building structures, it seem there is no impact resistance enhancement of fiber reinforced concrete applied to reactor containment building in the cases of impact velocity 150 m/sec considered in this study. However this results from the pre-stressing forces which introduce compressive stresses in concrete wall and dome section of reactor containment building. Nonetheless there may be benefits to apply fiber reinforced concrete to nuclear power plants. For double containment type reactor containment building, the outer structure is a reinforced concrete structure. The impact resistances for non pre-stressed cylindrical reactor containment buildings are enhanced by 23 to 47 % for 2 % polyamide fiber reinforced concretes and 1 % steel fiber reinforced concretes respectively. For other buildings such as auxiliary building, compound building and fuel storage building surrounding the reactor containment building, there are so many reinforced concrete walls which are anticipated some enhancements of impact resistance by using fiber reinforced concretes. And heavier or faster large civil aircraft impacts produce higher

  4. Reinforcement Magnitude: An Evaluation of Preference and Reinforcer Efficacy

    OpenAIRE

    Trosclair-Lasserre, Nicole M; Lerman, Dorothea C; Call, Nathan A; Addison, Laura R; Kodak, Tiffany

    2008-01-01

    Consideration of reinforcer magnitude may be important for maximizing the efficacy of treatment for problem behavior. Nonetheless, relatively little is known about children's preferences for different magnitudes of social reinforcement or the extent to which preference is related to differences in reinforcer efficacy. The purpose of the current study was to evaluate the relations among reinforcer magnitude, preference, and efficacy by drawing on the procedures and results of basic experimenta...

  5. Turbomachine blade reinforcement

    Science.gov (United States)

    Garcia Crespo, Andres Jose

    2016-09-06

    Embodiments of the present disclosure include a system having a turbomachine blade segment including a blade and a mounting segment coupled to the blade, wherein the mounting segment has a plurality of reinforcement pins laterally extending at least partially through a neck of the mounting segment.

  6. Reinforcing Saccadic Amplitude Variability

    Science.gov (United States)

    Paeye, Celine; Madelain, Laurent

    2011-01-01

    Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we…

  7. Reinforcement Magnitude: An Evaluation of Preference and Reinforcer Efficacy

    Science.gov (United States)

    Trosclair-Lasserre, Nicole M.; Lerman, Dorothea C.; Call, Nathan A.; Addison, Laura R.; Kodak, Tiffany

    2008-01-01

    Consideration of reinforcer magnitude may be important for maximizing the efficacy of treatment for problem behavior. Nonetheless, relatively little is known about children's preferences for different magnitudes of social reinforcement or the extent to which preference is related to differences in reinforcer efficacy. The purpose of the current…

  8. Elastomer Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Hudson, Jared L.; Krishnamoorti, Ramanan

    2009-01-01

    Elastomers are reinforced with functionalized, single-walled carbon nanotubes (SWNTs) giving them high-breaking strain levels and low densities. Cross-linked elastomers are prepared using amine-terminated, poly(dimethylsiloxane) (PDMS), with an average molecular weight of 5,000 daltons, and a functionalized SWNT. Cross-link densities, estimated on the basis of swelling data in toluene (a dispersing solvent) indicated that the polymer underwent cross-linking at the ends of the chains. This thermally initiated cross-linking was found to occur only in the presence of the aryl alcohol functionalized SWNTs. The cross-link could have been via a hydrogen-bonding mechanism between the amine and the free hydroxyl group, or via attack of the amine on the ester linage to form an amide. Tensile properties examined at room temperature indicate a three-fold increase in the tensile modulus of the elastomer, with rupture and failure of the elastomer occurring at a strain of 6.5.

  9. Large deformation and post-failure simulations of segmental retaining walls using mesh-free method (SPH)

    OpenAIRE

    Bui, H. H.; Kodikara, J. A.; Pathegama, R.; Bouazza, A.; Haque, A.

    2015-01-01

    Numerical methods are extremely useful in gaining insights into the behaviour of reinforced soil retaining walls. However, traditional numerical approaches such as limit equilibrium or finite element methods are unable to simulate large deformation and post-failure behaviour of soils and retaining wall blocks in the reinforced soil retaining walls system. To overcome this limitation, a novel numerical approach is developed aiming to predict accurately the large deformation and post-failure be...

  10. Analysis of the Seismic Performance of Site-Bolted Beam to Column Connections in Modularized Prefabricated Steel Structures

    Directory of Open Access Journals (Sweden)

    Xuechun Liu

    2017-01-01

    Full Text Available This paper proposes a site-bolted connection that is suitable for modularized prefabricated steel structures. Excellent ductility is achieved by various structural measures. Six connection specimens with different parameters were subjected to quasi-static loading tests and finite element analysis (FEA to determine the seismic performance of the proposed connection (e.g., hysteretic behavior, skeleton curve, ductility, and failure mode. The results of the tests and FEA showed that the connection underwent sufficient plastic deformation under cyclic loading and that its ultimate rotation angle could reach 0.09 rad. A clear plastic hinge formed on the beam before the connection failed, which suggests a ductile failure mode. The connection exhibited a wide hysteresis loop, which indicated good seismic performance. The results also showed that the connection does not slip under small earthquakes and could dissipate energy through slippage in the connection region under a moderate earthquake and through slippage in the connection region as well as plastic deformation at the beam end under a severe earthquake. The number of bolts was the main parameter that affected the seismic performance of the connection. The test and FEA results demonstrated that all six specimens had excellent seismic and ductile performance and an exceptional plastic rotation capacity.

  11. Soil settlement analysis in soft soil by using preloading system and prefabricated vertical draining runway of Kualanamu Airport

    Science.gov (United States)

    Roesyanto; Iskandar, R.; Silalahi, S. A.; Fadliansyah

    2018-02-01

    The method of soil improvement, using the combination of prefabricated vertical drain (PVD) and preloading, was used to accelerate the process of consolidation and the consolidation settlement in the runway of Kualanamu International Airport, which was constructed on the soft soil sediment like silty clay. In this research, the investigated area was the runway of Kualanamu International Airport zone I which had 11 meter-thickness of soft soil. Geotechnic instruments surveyed was settlement plate. Monitoring was done toward the behavior of landfill such as basic soil settlement. The result were compared with the analysis of finite element method of full scale in Mohr-Coulomb model by verifying the vertical drain of asymmetric unit cell and equivalent plane strain unit cell condition. The results of the research showed that there were an interesting behavior between the data in field observation and finite element of Mohr-Coulomb model. It was also found that the result of soil settlement of finite element method of Mohr-Coulomb model was closed to the result of settlement plate monitoring.

  12. Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

    International Nuclear Information System (INIS)

    Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

    2009-01-01

    The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

  13. Creep behavior of soil nail walls in high plasticity index (PI) soils : project summary.

    Science.gov (United States)

    2015-08-31

    Soil nailing is a convenient and economic : stabilization method for the reinforcement of existing : excavations by installing threaded steel bars into cuts : or slopes as wall construction progresses from top : down (Figure 1). An aspect of particul...

  14. Nano-Aramid Fiber Reinforced Polyurethane Foam

    Science.gov (United States)

    Semmes, Edmund B.; Frances, Arnold

    2008-01-01

    Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

  15. Flooding Effect on Earth Walls

    Directory of Open Access Journals (Sweden)

    Meysam Banimahd

    2010-12-01

    Full Text Available Earth building is a sustainable, environmentally friendly and economical method of construction that has been used worldwide for many centuries. For the past three decades, earth has seen a revival as a building material for a modern construction method due to its benefits in terms of low carbon content, low cost and energy involved during construction, as well as the fact that it is a sustainable technology of building. Climate change is influencing precipitation levels and patterns around the world, and as a consequence, flood risk is increasing rapidly. When flooding occurs, earth buildings are exposed to water by submersion, causing an increase in the degree of saturation of the earth structures and therefore a decrease of the suction between particles. This study investigated the effect of cycles of flooding (consecutive events of flooding followed by dry periods on earth walls. A series of characterization tests were carried out to obtain the physical and mechanical properties of the studied earth material. In a second stage, Flooding Simulation Tests (FST were performed to explore the earth walls’ response to repeated flooding events. The results obtained for the tested earth wall/samples with reinforced material (straw reveal hydraulic hysteresis when wall/samples are subject to cycles of wetting and drying.

  16. The Reinforcing Event (RE) Menu

    Science.gov (United States)

    Addison, Roger M.; Homme, Lloyd E.

    1973-01-01

    A motivational system, the Contingency Management System, uses contracts in which some amount of defined task behavior is demanded for some interval of reinforcing event. The Reinforcing Event Menu, a list of high probability reinforcing behaviors, is used in the system as a prompting device for the learner and as an aid for the administrator in…

  17. Carbon nanotube reinforced metal binder for diamond cutting tools

    DEFF Research Database (Denmark)

    Sidorenko, Daria; Mishnaevsky, Leon; Levashov, Evgeny

    2015-01-01

    The potential of carbon nanotube reinforcement of metallic binders for the improvement of quality and efficiency of diamond cutting wheels is studied. The effect of multi-walled carbon nanotube (MWCNT) reinforcement on the mechanical properties i.e. hardness, Young modulus, strength and deformation...... of grain size of the structural constituents of the binder, what in turn leads to the improved simultaneously hardness, Young modulus, plastic extension, bending strength and performances of the metallic binders. Comparing service properties of diamond end-cutting drill bits with and without MWCNT one...

  18. Autoshaping Chicks with Heat Reinforcement: The Role of Stimulus-Reinforcer and Response-Reinforcer Relations

    Science.gov (United States)

    Wasserman, Edward A.; And Others

    1975-01-01

    The present series of experiments attempted to analyze more fully the contributions of stimulus-reinforcer and response-reinforcer relations to autoshaping within a single conditioning situation. (Author)

  19. Study on reinforced concrete beams with helical transverse reinforcement

    Science.gov (United States)

    Kaarthik Krishna, N.; Sandeep, S.; Mini, K. M.

    2018-02-01

    In a Reinforced Concrete (R.C) structure, major reinforcement is used for taking up tensile stresses acting on the structure due to applied loading. The present paper reports the behavior of reinforced concrete beams with helical reinforcement (transverse reinforcement) subjected to monotonous loading by 3-point flexure test. The results were compared with identically similar reinforced concrete beams with rectangular stirrups. During the test crack evolution, load carrying capacity and deflection of the beams were monitored, analyzed and compared. Test results indicate that the use of helical reinforcement provides enhanced load carrying capacity and a lower deflection proving to be more ductile, clearly indicating the advantage in carrying horizontal loads. An analysis was also carried out using ANSYS software in order to compare the test results of both the beams.

  20. Degradation of Waterfront Reinforced Concrete Structures

    African Journals Online (AJOL)

    Key words: Degradation, reinforced concrete, Dar es Salaam port. Abstract—One of the ... especially corrosion of the reinforcement. ... Corrosion of steel reinforcement contributes .... cracks along the line of reinforcement bars and most of the ...

  1. Extended Plate and Beam Wall System: Concept Investigation and Initial Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [Partnership for Home Innovation, Upper Marlboro, MD (United States); Kochkin, V. [Partnership for Home Innovation, Upper Marlboro, MD (United States)

    2015-08-01

    A new and innovative High-R wall design, referred to as the Extended Plate & Beam (EP&B), is under development. The EP&B system uniquely integrates foam sheathing insulation with wall framing such that wood structural panels are installed exterior of the foam sheathing, enabling the use of standard practices for installation of drainage plane, windows and doors, claddings, cavity insulation, and the standard exterior foam sheathing installation approach prone to damage of the foam during transportation of prefabricated wall panels. As part of the ongoing work, the EP&B wall system concept has undergone structural verification testing and has been positively vetted by a group of industry stakeholders. Having passed these initial milestone markers, the advanced wall system design has been analyzed to assess cost implications relative to other advanced wall systems, undergone design assessment to develop construction details, and has been evaluated to develop representative prescriptive requirements for the building code. This report summarizes the assessment steps conducted to-date and provides details of the concept development.

  2. A New Model for Optimal Mechanical and Thermal Performance of Cement-Based Partition Wall.

    Science.gov (United States)

    Huang, Shiping; Hu, Mengyu; Huang, Yonghui; Cui, Nannan; Wang, Weifeng

    2018-04-17

    The prefabricated cement-based partition wall has been widely used in assembled buildings because of its high manufacturing efficiency, high-quality surface, and simple and convenient construction process. In this paper, a general porous partition wall that is made from cement-based materials was proposed to meet the optimal mechanical and thermal performance during transportation, construction and its service life. The porosity of the proposed partition wall is formed by elliptic-cylinder-type cavities. The finite element method was used to investigate the mechanical and thermal behaviour, which shows that the proposed model has distinct advantages over the current partition wall that is used in the building industry. It is found that, by controlling the eccentricity of the elliptic-cylinder cavities, the proposed wall stiffness can be adjusted to respond to the imposed loads and to improve the thermal performance, which can be used for the optimum design. Finally, design guidance is provided to obtain the optimal mechanical and thermal performance. The proposed model could be used as a promising candidate for partition wall in the building industry.

  3. A New Model for Optimal Mechanical and Thermal Performance of Cement-Based Partition Wall

    Directory of Open Access Journals (Sweden)

    Shiping Huang

    2018-04-01

    Full Text Available The prefabricated cement-based partition wall has been widely used in assembled buildings because of its high manufacturing efficiency, high-quality surface, and simple and convenient construction process. In this paper, a general porous partition wall that is made from cement-based materials was proposed to meet the optimal mechanical and thermal performance during transportation, construction and its service life. The porosity of the proposed partition wall is formed by elliptic-cylinder-type cavities. The finite element method was used to investigate the mechanical and thermal behaviour, which shows that the proposed model has distinct advantages over the current partition wall that is used in the building industry. It is found that, by controlling the eccentricity of the elliptic-cylinder cavities, the proposed wall stiffness can be adjusted to respond to the imposed loads and to improve the thermal performance, which can be used for the optimum design. Finally, design guidance is provided to obtain the optimal mechanical and thermal performance. The proposed model could be used as a promising candidate for partition wall in the building industry.

  4. South Oregon Coast Reinforcement.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1998-05-01

    The Bonneville Power Administration is proposing to build a transmission line to reinforce electrical service to the southern coast of Oregon. This FYI outlines the proposal, tells how one can learn more, and how one can share ideas and opinions. The project will reinforce Oregon`s south coast area and provide the necessary transmission for Nucor Corporation to build a new steel mill in the Coos Bay/North Bend area. The proposed plant, which would use mostly recycled scrap metal, would produce rolled steel products. The plant would require a large amount of electrical power to run the furnace used in its steel-making process. In addition to the potential steel mill, electrical loads in the south Oregon coast area are expected to continue to grow.

  5. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  6. Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation

    Science.gov (United States)

    Yan Wu; Siqun Wang; Dingguo Zhou; Cheng Xing; Yang Zhang; Zhiyong Cai

    2010-01-01

    Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (...

  7. Deep Reinforcement Fuzzing

    OpenAIRE

    Böttinger, Konstantin; Godefroid, Patrice; Singh, Rishabh

    2018-01-01

    Fuzzing is the process of finding security vulnerabilities in input-processing code by repeatedly testing the code with modified inputs. In this paper, we formalize fuzzing as a reinforcement learning problem using the concept of Markov decision processes. This in turn allows us to apply state-of-the-art deep Q-learning algorithms that optimize rewards, which we define from runtime properties of the program under test. By observing the rewards caused by mutating with a specific set of actions...

  8. Ultimate load capacity assessment of reinforced concrete shell structures

    International Nuclear Information System (INIS)

    Gupta, Amita; Singh, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1993-01-01

    The objective of this study is to develop capability for prediction of ultimate load capacity of reinforced concrete shell structures. The present finite element code ULCA (Ultimate Load Capacity Assessment) adopts a degenerate concept of formulating general isoparametric shell element with a layered approach in the thickness direction. Different failure modes such as crushing, tensile cracking and reinforcement yielding are recognised for various problems. The structure fails by crushing of concrete when the concrete strain/stress reaches the ultimate stress or strain of concrete. Material nonlinearities as a result of tension cracking, tension stiffening between reinforcement and concrete in cracked region and yielding of reinforcement are considered along with geometric nonlinearity. Thus with this code it is possible to predict the pressure at which the first cracking, first through thickness cracking, first yielding of reinforcement occurs. After validating the code with few bench mark problems for different failure modes a reinforced concrete nuclear containment is analysed for its ultimate capacity and the results are matched with the published results. Further the ultimate load capacity of outer containment wall of Narora Atomic Power Station is predicted. It is observed that containment fails in membrane region and has a sufficient margin against design pressure. (author). 9 refs., 56 figs., 3 tabs., 1 appendix with 4 tabs

  9. Prefabrication of 3D cartilage contructs: towards a tissue engineered auricle--a model tested in rabbits.

    Directory of Open Access Journals (Sweden)

    Achim von Bomhard

    Full Text Available The reconstruction of an auricle for congenital deformity or following trauma remains one of the greatest challenges in reconstructive surgery. Tissue-engineered (TE three-dimensional (3D cartilage constructs have proven to be a promising option, but problems remain with regard to cell vitality in large cell constructs. The supply of nutrients and oxygen is limited because cultured cartilage is not vascular integrated due to missing perichondrium. The consequence is necrosis and thus a loss of form stability. The micro-surgical implantation of an arteriovenous loop represents a reliable technology for neovascularization, and thus vascular integration, of three-dimensional (3D cultivated cell constructs. Auricular cartilage biopsies were obtained from 15 rabbits and seeded in 3D scaffolds made from polycaprolactone-based polyurethane in the shape and size of a human auricle. These cartilage cell constructs were implanted subcutaneously into a skin flap (15 × 8 cm and neovascularized by means of vascular loops implanted micro-surgically. They were then totally enhanced as 3D tissue and freely re-implanted in-situ through microsurgery. Neovascularization in the prefabricated flap and cultured cartilage construct was analyzed by microangiography. After explantation, the specimens were examined by histological and immunohistochemical methods. Cultivated 3D cartilage cell constructs with implanted vascular pedicle promoted the formation of engineered cartilaginous tissue within the scaffold in vivo. The auricles contained cartilage-specific extracellular matrix (ECM components, such as GAGs and collagen even in the center oft the constructs. In contrast, in cultivated 3D cartilage cell constructs without vascular pedicle, ECM distribution was only detectable on the surface compared to constructs with vascular pedicle. We demonstrated, that the 3D flaps could be freely transplanted. On a microangiographic level it was evident that all the skin flaps

  10. Application of global elements to a reinforced concrete structure

    International Nuclear Information System (INIS)

    Morand, O.

    1994-01-01

    The dimensioning of nuclear facilities requires to take into account the possible risk of earthquakes. However such installations are generally complex structures with reinforced concrete poles, walls, beams and porches. In this study, a seismic analysis of such a structure is proposed. The use of the Castem 2000 global element code was attempted to dynamically simulate the behaviour of the reinforced concrete elements. However, no suitable modeling has been found for the storeys, the functioning of which being dominated by carrying walls. Concerning the porch-type storeys, monotonous static loads were simulated and provided information on the local and global behaviour of these structures. Thus, representative global elements could be realized for these structures. Results obtained are satisfactory for these storeys which essentially undergo a bending deformation. (J.S.)

  11. Development of connecting method for mechanically cut reinforced concrete blocks

    International Nuclear Information System (INIS)

    Nishiuchi, Tatsuo

    2005-01-01

    The purpose of the study is to develop a practical method of disposing and recycling in dismantled reinforced concrete structures. We have devised a new method in which mechanically cut reinforced concrete blocks are connected and they are reused as a structural beam. In this method, concrete blocks are connected with several steel bars and the connected surface is wrapped with a fiber sheet. We verified that the load capacity of renewal beams was considerably large as same as that of continuous structural beams on the basis of experimental as well as numerical analysis results. As far as construction cost of reinforced concrete walls are concerned, we demonstrated that the cost of this method is slightly lower than that of the plan to use new and recycle materials. (author)

  12. Electrical resisitivity of mechancially stablized earth wall backfill

    Science.gov (United States)

    Snapp, Michael; Tucker-Kulesza, Stacey; Koehn, Weston

    2017-06-01

    Mechanically stabilized earth (MSE) retaining walls utilized in transportation projects are typically backfilled with coarse aggregate. One of the current testing procedures to select backfill material for construction of MSE walls is the American Association of State Highway and Transportation Officials standard T 288: ;Standard Method of Test for Determining Minimum Laboratory Soil Resistivity.; T 288 is designed to test a soil sample's electrical resistivity which correlates to its corrosive potential. The test is run on soil material passing the No. 10 sieve and believed to be inappropriate for coarse aggregate. Therefore, researchers have proposed new methods to measure the electrical resistivity of coarse aggregate samples in the laboratory. There is a need to verify that the proposed methods yield results representative of the in situ conditions; however, no in situ measurement of the electrical resistivity of MSE wall backfill is established. Electrical resistivity tomography (ERT) provides a two-dimensional (2D) profile of the bulk resistivity of backfill material in situ. The objective of this study was to characterize bulk resistivity of in-place MSE wall backfill aggregate using ERT. Five MSE walls were tested via ERT to determine the bulk resistivity of the backfill. Three of the walls were reinforced with polymeric geogrid, one wall was reinforced with metallic strips, and one wall was a gravity retaining wall with no reinforcement. Variability of the measured resistivity distribution within the backfill may be a result of non-uniform particle sizes, thoroughness of compaction, and the presence of water. A quantitative post processing algorithm was developed to calculate mean bulk resistivity of in-situ backfill. Recommendations of the study were that the ERT data be used to verify proposed testing methods for coarse aggregate that are designed to yield data representative of in situ conditions. A preliminary analysis suggests that ERT may be utilized

  13. Structural optimization of reinforced concrete container for radioactive wastes

    International Nuclear Information System (INIS)

    Tamura, M.

    1984-01-01

    A structural optimization study of reinforced concrete container for transportation and disposal of the low level radioactive waste generated in Brazilian nuclear power plants. The code requires the structural integrity of these containers when subjected to fall from specified height, avoiding environmental contamination. The structural optimization allows material and transportation cost reduction by container wall thickness reduction. The structural analysis is performed by tridimensional mathematical model using finite element method. (Author) [pt

  14. Dynamic Response of Reinforced Soil Systems. Volume 1. Report

    Science.gov (United States)

    1993-03-01

    Elements Failure Modes Ai,’Ilast Exposed walls, roof, arch Bruachiig Airbuast/fragment impulse Floor Flexure Fragment penetration Sur;ed walIs, flour , roof...completed panels used in all centrifuge tests are presented in Figures 64 and 65. Connection: For all steel reinforced panels, glue was applied to both the...High Stress Experiments on Soil," Geotechnical Testing Journal , Vol. 10, No. 4, pp. 192-202, Dec 1987. 11. Seaman, L., One-Dimensional Stress Wave

  15. How the deposition of cellulose microfibrils builds cell wall architecture

    NARCIS (Netherlands)

    Emons, A.M.C.; Mulder, B.M.

    2000-01-01

    Cell walls, the extracytoplasmic matrices of plant cells, consist of an ordered array of cellulose microfibrils embedded in a matrix of polysaccharides and glycoproteins. This construction is reminiscent of steel rods in reinforced concrete. How a cell organizes these ordered textures around itself,

  16. Reinforced seal component

    International Nuclear Information System (INIS)

    Jeanson, G.M.; Odent, R.P.

    1980-01-01

    The invention concerns a seal component of the kind comprising a soft sheath and a flexible reinforcement housed throughout the entire length of the sheath. The invention enables O ring seals to be made capable of providing a radial seal, that is to say between two sides or flat collars of two cylindrical mechanical parts, or an axial seal, that is to say between two co-axial axisymmetrical areas. The seal so ensured is relative, but it remains adequately sufficient for many uses, for instance, to ensure the separation of two successive fixed blading compartments of axial compressors used in gas diffusion isotope concentration facilities [fr

  17. Manifold Regularized Reinforcement Learning.

    Science.gov (United States)

    Li, Hongliang; Liu, Derong; Wang, Ding

    2018-04-01

    This paper introduces a novel manifold regularized reinforcement learning scheme for continuous Markov decision processes. Smooth feature representations for value function approximation can be automatically learned using the unsupervised manifold regularization method. The learned features are data-driven, and can be adapted to the geometry of the state space. Furthermore, the scheme provides a direct basis representation extension for novel samples during policy learning and control. The performance of the proposed scheme is evaluated on two benchmark control tasks, i.e., the inverted pendulum and the energy storage problem. Simulation results illustrate the concepts of the proposed scheme and show that it can obtain excellent performance.

  18. Automatized welding equipment for manufacturing steel cells for special buildings

    International Nuclear Information System (INIS)

    Weikert, F.; Winter, K.P.

    1986-01-01

    In GDR's nuclear power plant construction, reinforced concrete wall cells are used to construct pressure and full pressure containments for WWER-440 and WWER-1000 reactors, respectively. Welding processes for the prefabrication of steel cells as reinforcement have been automatized in order to increase both labor productivity and quality assurance. 11 figs

  19. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  20. The Reinforcement Learning Competition 2014

    OpenAIRE

    Dimitrakakis, Christos; Li, Guangliang; Tziortziotis, Nikoalos

    2014-01-01

    Reinforcement learning is one of the most general problems in artificial intelligence. It has been used to model problems in automated experiment design, control, economics, game playing, scheduling and telecommunications. The aim of the reinforcement learning competition is to encourage the development of very general learning agents for arbitrary reinforcement learning problems and to provide a test-bed for the unbiased evaluation of algorithms.

  1. Recycling of Reinforced Plastics

    Science.gov (United States)

    Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri

    2014-02-01

    This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.

  2. Ultimate shearing strength of aseismatic walls with many small holes for reactor buildings

    International Nuclear Information System (INIS)

    Yoshizaki, Seiji; Ezaki, Tetsuro; Korenaga, Takeyoshi; Sotomura, Kentaro.

    1984-01-01

    The aseismatic walls for reactor buildings have complicated forms, and are characterized by large wall thickness and high reinforcement ratio as compared with ordinary aseismatic walls. The forms are mainly box, cylinder or irregular polygonal prism and their combination. The design of the walls with many small holes has been performed on the basis of the reinforced concrete structure calculation standard of the Architectural Institute of Japan, following the case with large opening. When there are many small holes, the arrangement of reinforcement for the openings becomes complex, and the construction is difficult. It is necessary to rationalize the design and to simplify the reinforcement work. Under the background like this, the experiment to examine the shearing property in bending of the aseismatic walls with many small holes for reactor buildings was carried out, and horizontal loading test was performed on 43 specimens. The method of calculating the ultimate shearing strength of a wall without opening was proposed, and the method of applying it to a wall with many small holes is shown. The experimental method and the results, the examination of the experimental results, and the ultimate shearing strength of the aseismatic walls are reported. (Kako, I.)

  3. HABITAR Y TECNOLOGÍA EN LA VIVIENDA PREFABRICADA CONTEMPORÁNEA / Living and technology in the contemporary prefabricated home

    Directory of Open Access Journals (Sweden)

    Carmen Guerra Hoyos

    2012-05-01

    Full Text Available RESUMEN El texto revisa las relaciones entre tecnología, habitar y contexto sociocultural a lo largo del ciclo de lo moderno, indagando en la situación actual de los mismos. Si lo que caracteriza el pensamiento contemporáneo es la comprensión y la revisión del periodo de la modernidad, debemos extender ese procedimiento a la arquitectura si pretendemos integrar las herramientas y las soluciones habitacionales y constructivas de nuestra tradición disciplinar en el presente. Trata de realizar un repaso genealógico que quiere recordar la utilidad y el sentido que términos como cabaña, máquina o caravana, pueden tener para la comprensión de la vivienda prefabricada contemporánea. También se procura el acercamiento a dos casos concretos, la casa de los Eames y el pabellón solar de los Smithson, para explorar la superación de algunas de los problemas básicos detectados en la temática de estudio. Por último, y a modo de conclusiones, se abordan algunas líneas de dilatación en los modos de hacer y pensamiento contemporáneos. SUMMARY The paper reviews the relationship between technology, living and socio–cultural context, during the modern cycle, delving into their current states. If understanding and review of the period of modernity characterize contemporary thought, we must extend this procedure to architecture if we expect to integrate the tools and housing and construction solutions of our disciplinary tradition into the present. A genealogical review is made to recall the utility and meaning that terms such as cabin, machine or caravan may have for understanding the contemporary prefabricated home. Also, two specific cases are approached, the Eames House and the Smithson’s Solar Pavilion, in an effort to explore how some of the basic problems identified in the subject matter are overcome. Finally, some aspects of contemporary methods of production and thought are expanded upon as a conclusion.

  4. Investigating the Influence of Prefabricated Insole with Medial Flange on Forefoot and Rearfoot Alignment Changes at Females with Flexible Flat Foot

    Directory of Open Access Journals (Sweden)

    Fatemeh Dehghani

    2015-01-01

    Full Text Available Objective: Flexible flat foot is one the most common extremities diseases happen among adults, this causes change in foot, tibia, and higher joints alignment, pain and certain complications in upper joints and soft tissues. This study aimed to investigate differences in foot direction among patients with flexible flat feet as so called foot static response to a certain prefabricated insole. Materials & Methods: It was a quasi-experimental study and patients were consisted of 32 female with flat feet in range of 18 to 28 years old and to measure differences a laser device was used. The rear foot angle amount which is calculated by investigating the heel valgus angle and the forefoot angle amount which is calculated by investigating leg angle and forefoot, both assessed at barefoot condition and with medial flange insole mode. Results: Results showed that by using the insole there is a significant decrease in direction of anterior line angle (P<0.001. At mean, by using medial flange insole 3.5 degrees decrease at forefoot angle and 2.5 degrees decrease at heel angle was observed (P<0.001. Conclusion: This study showed that the prefabricated insole with high internal septum could normalize the direction of foot. Namely, it corrected the heel angle and leg deviations. Moreover, the NAS line despite of specifying the leg changes, it represents the influence of orthoses on this section.

  5. Constitutive model for reinforced concrete

    NARCIS (Netherlands)

    Feenstra, P.H.; Borst, de R.

    1995-01-01

    A numerical model is proposed for reinforced-concrete behavior that combines the commonly accepted ideas from modeling plain concrete, reinforcement, and interaction behavior in a consistent manner. The behavior of plain concrete is govern by fracture-energy-level-based formulation both in tension

  6. Quenched Reinforcement Exposed to Fire

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2006-01-01

    .0% is seldom found in “slack” (not prestressed) reinforcement, but 2.0% stresses might be relevant for reinforcement in T shaped cross sections and for prestressed structures, where large strains can be applied. All data are provided in a “HOT” condition during a fire and in a “COLD” condition after a fire...

  7. Tangible Reinforcers: Bonuses or Bribes?

    Science.gov (United States)

    O'Leary, K. Daniel; And Others

    1972-01-01

    Objections to the use of tangible reinforcers, such as prizes, candy, cigarettes, and money, are discussed. Treatment programs using tangible reinforcers are recommended as powerful modifers of behavior to be implemented only after less powerful means of modification have been tried. (Author)

  8. Comparison of theoretical and test results on shear wall seismic response

    International Nuclear Information System (INIS)

    Gantenbein, F.; Wang, F.; Dalbera, J.

    1991-01-01

    As reinforced concrete shear walls are important resisting components of buildings in nuclear power facilities, it is important to study their ultimate behavior under dynamic loading. An experimental and analytical work has been undertaken on shear walls with and without openings, in order to develop and validate their model. This paper is related to the walls without openings. While pretest calculations have already been reported (Wang and al. 1989) and the test results are given in Gantenbein and al. 1991, this paper is mainly related to the comparison of test and calculation results on the wall initial stiffness and the time history of the wall motion

  9. Multi-level nonlinear modeling verification scheme of RC high-rise wall buildings

    OpenAIRE

    Alwaeli, W.; Mwafy, A.; Pilakoutas, K.; Guadagnini, M.

    2017-01-01

    Earthquake-resistant reinforced concrete (RC) high-rise wall buildings are designed and detailed to respond well beyond the elastic range under the expected earthquake ground motions. However, despite their considerable section depth, in terms of analysis, RC walls are still often treated as linear elements, ignoring the effect of deformation compatibility. Due to the limited number of available comprehensive experimental studies on RC structural wall systems subjected to cycling loading, few...

  10. Water Power in The Wilderness: The History of Bonneville Lock and Dam

    Science.gov (United States)

    1997-01-01

    yards of material. Reinforced concrete cutoff walls at each abutment and reinforced concrete coun- terfort type upstream wing walls, along with...at the ends of the dam, the abutment Blasting of boulder no. 8 for navigation channel at Cascade Rapids . walls had to be built over 150 feet high...completion of the entire north section during 1936-37, the contractors placed a prefabricated struc- tural steel cofferdam over the crest section

  11. Partition wall structure in spent fuel storage pool and construction method for the partition wall

    International Nuclear Information System (INIS)

    Izawa, Masaaki

    1998-01-01

    A partitioning wall for forming cask pits as radiation shielding regions by partitioning inside of a spent fuel storage pool is prepared by covering both surface of a concrete body by shielding metal plates. The metal plate comprises opposed plate units integrated by welding while sandwiching a metal frame as a reinforcing material for the concrete body, the lower end of the units is connected to a floor of a pool by fastening members, and concrete is set while using the metal plate of the units as a frame to form the concrete body. The shielding metal plate has a double walled structure formed by welding a lining plate disposed on the outer surface of the partition wall and a shield plate disposed to the inner side. Then the term for construction can be shortened, and the capacity for storing spent fuels can be increased. (N.H.)

  12. Bond characteristics of steel fiber and deformed reinforcing steel bar embedded in steel fiber reinforced self-compacting concrete (SFRSCC)

    Science.gov (United States)

    Aslani, Farhad; Nejadi, Shami

    2012-09-01

    Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fiber and SCC firstly. Based on the available experimental results, the current analytical steel fiber pullout model (Dubey 1999) is modified by considering the different SCC properties and different fiber types (smooth, hooked) and inclination. In order to take into account the effect of fiber inclination in the pullout model, apparent shear strengths ( τ ( app)) and slip coefficient ( β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle ( ϕ). Furthurmore, steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of steel fibers. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components containing reinforcement and steel fibers

  13. Seismic retrofitting of timber framed walls

    Directory of Open Access Journals (Sweden)

    Gonçalves, A. M.

    2014-12-01

    Full Text Available After the 1755 earthquake that destroyed Lisbon, an innovative anti-seismic structural system was developed consisting of a timber skeleton, that included timber framed masonry walls. After more than 250 years these structures need rehabilitation to face the present demands. The research presented in this paper aimed at experimentally characterizing the cyclic behaviour of timber framed walls reinforced with three different methods, namely: (i elastic-plastic dampers on diagonal braces, (ii reinforcement of timber connections with steel plates, (iii application of a reinforced rendering. The elastic-plastic damper showed an unsymmetrical behaviour and some difficulties to implement in practice. The strengthening with reinforced render led to an initial stiffness increase but showed a limited deformation capacity. The walls with reinforcing steel plates at the timber connections showed the best behaviour in terms of strength, stiffness and energy dissipation.Después del terremoto de 1755 que destruyó Lisboa, un sistema estructural antisísmico muy innovador fue desarrollado. El sistema consistió en un esqueleto de madera, que incluyó la construcción de muros de mampostería con un entramado de madera. Transcurridos más de 250 años, estas estructuras necesitan rehabilitación para poder hacer frente a los requisitos estructurales actuales. La investigación presentada en este trabajo tiene como objetivo caracterizar experimentalmente el comportamiento cíclico de los muros con entramado de madera reforzados con tres métodos diferentes: (i amortiguadores elasto-plásticos, (ii refuerzo de las conexiones de madera con placas de acero, (iii aplicación de un mortero reforzado. El amortiguador elasto-plástico mostró un comportamiento asimétrico y algunas dificultades para aplicarlo en la práctica. El refuerzo con mortero reforzado condujo a un aumento de la rigidez inicial, pero reveló una capacidad de deformación limitada. Los muros con

  14. Experimental report of precast prestressed concrete shear wall. Precast prestressed concrete taishinheki no jikken hokoku

    Energy Technology Data Exchange (ETDEWEB)

    Takada, K.; Komura, M.; Sakata, H.; Senoo, M. (Fudo Building Research Co. Ltd., Tokyo (Japan))

    1993-07-30

    The present report outlines the multi-story precast prestressed concrete earthquake-proof wall (PC shear wall system). The PC shear wall is a precast wall which internally contains the columns and beams as a unit. Therefore, the present system integrates the walls, columns and beams without beam-framing installation for the intermediate stories. It can simplify the concreting in site and ease the construction of building. For the system development, experiment was made on the deformation, sliding, yield strength and destruction state of the shear wall. Used were four types of test unit which are different in both reinforcement and connection methods. The test force was given by a hydraulically drawing jack. In the experiment, the four types were compared in destruction state, relation between load and deformation, yield strength, and strain of main column reinforcing bars and wall connection reinforcing bars. PC shear wall system-based design was studied from the experimental result. The shear wall in which there occurred both bending and shearing deformations was modeled by changing to a brace unit. Divided into bending deformation and shearing deformation, the deformation was calculated, which concluded that the shearing deformation dominates in the present system. 15 figs., 4 tabs.

  15. Stripping demolition of reinforced concrete by electric heating method

    International Nuclear Information System (INIS)

    Nakagawa, Wahei; Nishita, Kiwamu; Kasai, Yoshio

    1993-01-01

    The present paper describes the procedures and results of a series of experiments the authors conducted to verify the efficiency of the electric heating method, previously proposed for so-called stripping demolition by applying electric current through reinforcing bars. In this method, a low voltage high current is run from one end to the other of a reinforcing bar or bars existing in a concrete structure, inducing intense heat in the bar(s) which in its turn brings about cracks in the surrounding concrete mass, facilitating secondary demolition by hammer picks or other means. The experiments were performed on full-scale biological shield wall mock-ups of a BWR and a small reactor. The results of the experiments are summarized as follows. (1) When electric current is applied through reinforcing bars, the bond between concrete and bars is loosened, and cracks start from one bar and progress toward other bars. Under appropriate conditions, the cracks in concrete run from the contact surface at one bar all the way to its the contact surface on another bar. (2) Cracks appear and grow only between two electrodes between which current is applied, not extending out of the area thus defined. (3) The concrete in the region closer to a current-bearing bar is intensely heated, whereas the concrete far from the bars remains nearly unheated. (4) Concrete walls after electric heating of bars disintegrates, if demolished with hammers, with the covering concrete are removed from the remaining portion of the structure together with heated bars, in shapes of flakes. (5) The reinforced concrete collapses in massive pieces of concrete, without generating much dust as is the case with the demolition of a concrete structure not heated by electricity. Results of the experiments show that the electric heating method is worth applying also to the demolition of nuclear power plants where concrete in the radioactivated surface region of shield walls needs to be stripped off in flakes

  16. Interaction analysis of back-to-back mechanically stabilized earth walls

    Directory of Open Access Journals (Sweden)

    Sadok Benmebarek

    2016-10-01

    Full Text Available Back-to-back mechanically stabilized earth walls (BBMSEWs are encountered in bridge approaches, ramp ways, rockfall protection systems, earth dams, levees and noise barriers. However, available design guidelines for BBMSEWs are limited and not applicable to numerical modeling when back-to-back walls interact with each other. The objective of this paper is to investigate, using PLAXIS code, the effects of the reduction in the distance between BBMSEW, the reinforcement length, the quality of backfill material and the connection of reinforcements in the middle, when the back-to-back walls are close. The results indicate that each of the BBMSEWs behaves independently if the width of the embankment between mechanically stabilized earth walls is greater than that of the active zone. This is in good agreement with the result of FHWA design guideline. However, the results show that the FHWA design guideline underestimates the lateral earth pressure when back-to-back walls interact with each other. Moreover, for closer BBMSEWs, FHWA design guideline strongly overestimates the maximum tensile force in the reinforcement. The investigation of the quality of backfill material shows that the minor increase in embankment cohesion can lead to significant reductions in both the lateral earth pressure and the maximum tensile force in geosynthetic. When the distance between the two earth walls is close to zero, the connection of reinforcement between back-to-back walls significantly improves the factor of safety.

  17. Seismic and Power Generation Performance of U-Shaped Steel Connected PV-Shear Wall under Lateral Cyclic Loading

    OpenAIRE

    Zhang, Hongmei; Dong, Jinzhi; Duan, Yuanfeng; Lu, Xilin; Peng, Jinqing

    2014-01-01

    BIPV is now widely used in office and residential buildings, but its seismic performance still remained vague especially when the photovoltaic (PV) modules are installed on high-rise building facades. A new form of reinforced concrete shear wall integrated with photovoltaic module is proposed in this paper, aiming to apply PV module to the facades of high-rise buildings. In this new form, the PV module is integrated with the reinforced concrete wall by U-shaped steel connectors through embedd...

  18. Abdominal wall fat pad biopsy

    Science.gov (United States)

    Amyloidosis - abdominal wall fat pad biopsy; Abdominal wall biopsy; Biopsy - abdominal wall fat pad ... is the most common method of taking an abdominal wall fat pad biopsy . The health care provider cleans the ...

  19. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  20. Nonlinear analysis techniques of block masonry walls in nuclear power plants

    International Nuclear Information System (INIS)

    Hamid, A.A.; Harris, H.G.

    1986-01-01

    Concrete masonry walls have been used extensively in nuclear power plants as non-load bearing partitions serving as pipe supports, fire walls, radiation shielding barriers, and similar heavy construction separations. When subjected to earthquake loads, these walls should maintain their structural integrity. However, some of the walls do not meet design requirements based on working stress allowables. Consequently, utilities have used non-linear analysis techniques, such as the arching theory and the energy balance technique, to qualify such walls. This paper presents a critical review of the applicability of non-linear analysis techniques for both unreinforced and reinforced block masonry walls under seismic loading. These techniques are critically assessed in light of the performance of walls from limited available test data. It is concluded that additional test data are needed to justify the use of nonlinear analysis techniques to qualify block walls in nuclear power plants. (orig.)

  1. Ceramic fiber reinforced filter

    Science.gov (United States)

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  2. Effect of dewatering on seismic performance of multi-anchor wall due to high ground water level

    Science.gov (United States)

    Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo; Sato, Hiroki

    2017-10-01

    Previous research reported that the ground water in the backfill of reinforced soil wall made it deteriorate. According to the damage investigation of Great East Earthquake 2011, the reinforced soil structure due to high ground water level by seismic wave were deformed remarkably. Some of them classified ultimate limit state or restorability limit state. However, more than 90% of reinforced soil structure, which suffered from this earthquake, were classified into no damage condition. Therefore, it is necessary that the seismic behaviors of multi-anchor wall due to seepage flow should be clarified in order to adopt the performance-based design in such reinforced soil structure. In this study, a series of centrifugal shaking table tests were conducted to investigate the seismic behavior of multi-anchor wall due to high ground water level. The reinforced drainage pipes were installed into the backfill in order to verify the dewatering effect and additional reinforcement. Furthermore, to check only the dewatering effect, the model tests was carried out with several ground water table that was modeled the case reinforced drainage pipes installed. The test results show unique behavior of reinforced region that moved integrally. This implies that the reinforced region has been behaved as if it became one mass, and this behavior make this structure increase seismic performance. Thus, the effectiveness of dewatering was observed remarkably because of decreasing the inertial force during earthquake.

  3. [Factors influencing the quality of life of elderly living in a pre-fabricated housing complex in the Sichuan earthquake area].

    Science.gov (United States)

    Guo, Hong-Xia; Chen, Hong; Wong, Teresa Bik-Kwan Tsien; Chen, Qian; Au, May-Lan; Li, Yun

    2012-02-01

    The 2008 Sichuan Earthquake caused great damage to the environment and property. In the aftermath, many citizens were relocated to live in newly constructed prefabricated (prefab) communities. This paper explored the current quality of life (QOL) of elderly residents living in prefabricated communities in areas damaged by the Sichuan earthquake and identified factors of influence on QOL values. The ultimate objective was to provide evidence-based guidance for heath improvement measures. The authors used the short form WHOQOL-BREF to assess the quality of life of 191 elderly residents of prefabricated communities in the Sichuan Province 2008 earthquake zone. A Student's t-test, variance analysis, and stepwise multivariate regression methods were used to test the impact of various factors on QOL. Results indicate the self-assessed QOL of participants as good, although scores in the physical (average 56.2) and psychological (average 45.7) domains were significantly lower than the norm in China. Marital status, capital loss in the earthquake, number of children, level of perceived stress, income, interest, and family harmony each correlated with at least one of the short form WHOQOL-BREF domains in t-test and one-way analyses. After excluding for factor interaction effects using multivariate regression, we found interest, family harmony, monthly income and stress to be significant predictors of physical domain QOL, explaining 13.8% of total variance. Family harmony and interest explained 15.3% of total variance for psychological domain QOL; stress, marital status, family harmony, capital loss in the earthquake, number of children and interest explained 19.5% of total variance for social domain QOL; and stress, family harmony and interest explained 16.5% of total variance for environmental domain QOL. Family harmony and interest were significant factors across all domains, while others influenced a smaller proportion. Quality of life for elderly living in prefab

  4. Rocker-sole footwear versus prefabricated foot orthoses for the treatment of pain associated with first metatarsophalangeal joint osteoarthritis: study protocol for a randomised trial

    Science.gov (United States)

    2014-01-01

    Background Osteoarthritis affecting the first metatarsophalangeal joint of the foot is a common condition which results in pain, stiffness and impaired ambulation. Footwear modifications and foot orthoses are widely used in clinical practice to treat this condition, but their effectiveness has not been rigorously evaluated. This article describes the design of a randomised trial comparing the effectiveness of rocker-sole footwear and individualised prefabricated foot orthoses in reducing pain associated with first metatarsophalangeal joint osteoarthritis. Methods Eighty people with first metatarsophalangeal joint osteoarthritis will be randomly allocated to receive either a pair of rocker-sole shoes (MBT® Matwa, Masai Barefoot Technology, Switzerland) or a pair of individualised, prefabricated foot orthoses (Vasyli Customs, Vasyli Medical™, Queensland, Australia). At baseline, the biomechanical effects of the interventions will be examined using a wireless wearable sensor motion analysis system (LEGSys™, BioSensics, Boston, MA, USA) and an in-shoe plantar pressure system (Pedar®, Novel GmbH, Munich, Germany). The primary outcome measure will be the pain subscale of the Foot Health Status Questionnaire (FHSQ), measured at baseline and 4, 8 and 12 weeks. Secondary outcome measures will include the function, footwear and general foot health subscales of the FHSQ, severity of pain and stiffness at the first metatarsophalangeal joint (measured using 100 mm visual analog scales), global change in symptoms (using a 15-point Likert scale), health status (using the Short-Form-12® Version 2.0 questionnaire), use of rescue medication and co-interventions to relieve pain, the frequency and type of self-reported adverse events and physical activity levels (using the Incidental and Planned Activity Questionnaire). Data will be analysed using the intention to treat principle. Discussion This study is the first randomised trial to compare the effectiveness of rocker

  5. Welding distortion control in double walled KSTAR vacuum vessel fabrication

    International Nuclear Information System (INIS)

    Oh, D. W.; Lee, G. T.; Kim, H. K.; Yang, H. L.; Bak, J. S.

    2004-01-01

    The KSTAR(Korea Superconducting Tokamak Advanced Research) vacuum vessel is designed to be a double walled structure made of 12mm thick 316LN stainless steel with a D shaped cross-section about 4 m height. Vacuum vessel was pre-fabricated in two parts, 180 degree and 157.5 degree sectors in toroidal direction to meet the transportation purpose. These two parts have to be welded on site with ±2mm allowable fabrication tolerances. 1/3 scaled mock-up model was used to estimate the welding distortion and to ensure the weld quality of vacuum vessel. Gas Tungsten Arc Welding(GTAW), which has been approved by procedure qualification test, was used during mock-up test and vacuum vessel site fabrication. Welding distortion could be managed by allowing for distortion in opposite direction, by applying high restraint using lots of strong backs, by controlling the welding heat input with symmetrical welding sequence. The integrity of the site welding joint was assured by radiographic test, ultrasonic test and leak test with helium detecting method

  6. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Aklik, P.

    2012-01-01

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author) [de

  7. Energy Absorption Capacity in Natural Fiber Reinforcement Composites Structures

    Directory of Open Access Journals (Sweden)

    Elías López-Alba

    2018-03-01

    Full Text Available The study of natural fiber reinforcement composite structures has focused the attention of the automobile industry due to the new regulation in relation to the recyclability and the reusability of the materials preserving and/or improving the mechanical characteristics. The influence of different parameters on the material behavior of natural fiber reinforced plastic structures has been investigated, showing the potential for transport application in energy absorbing structures. Two different woven fabrics (twill and hopsack made of flax fibers as well as a non-woven mat made of a mixture of hemp and kenaf fibers were employed as reinforcing materials. These reinforcing textiles were impregnated with both HD-PE (high-density polyethylen and PLA (polylactic acid matrix, using a continuous compression molding press. The impregnated semi-finished laminates (so-called organic sheets were thermoformed in a second step to half-tubes that were assembled through vibration-welding process to cylindric crash absorbers. The specimens were loaded by compression to determine the specific energy absorption capacity. Quasi-static test results were compared to dynamic test data obtained on a catapult arrangement. The differences on the specific energies absorption (SEA as a function of different parameters, such as the wall thickness, the weave material type, the reinforced textiles, and the matrix used, depending on the velocity rate application were quantified. In the case of quasi-static analysis it is observed a 20% increment in the SEA value when wove Hopsack fabric reinforcement is employed. No velocity rate influence from the material was observed on the SEA evaluation at higher speeds used to perform the experiments. The influence of the weave configuration (Hopsack seems to be more stable against buckling effects at low loading rates with 10% higher SEA values. An increase of SEA level of up to 72% for PLA matrix was observed when compared with HD

  8. Methodical Specifics of Thermal Experiments with Thin Carbon Reinforced Plates

    Directory of Open Access Journals (Sweden)

    O. V. Denisov

    2015-01-01

    Full Text Available Polymer composite materials (CM are widely used in creation of large space constructions, especially reflectors of space antennas. Composite materials should provide high level of specific stiffness and strength for space structures. Thermal conductivity in reinforcement plane is a significant factor in case of irregular heating space antennas. Nowadays, data on CM reinforcement plane thermal conductivity are limited and existing methods of its defining are imperfect. Basically, traditional methods allow us to define thermal conductivity in perpendicular direction towards the reinforcement plane on the samples of round or rectangular plate. In addition, the thickness of standard samples is larger than space antenna thickness. Consequently, new methods are required. Method of contact heating, which was developed by BMSTU specialists with long hollow carbon beam, could be a perspective way. This article is devoted to the experimental method of contact heating on the thin carbon plates.Thermal tests were supposed to provide a non-stationary temperature field with a gradient being co-directional with the plane reinforcement in the material sample. Experiments were conducted in vacuum chamber to prevent unstructured convection. Experimental thermo-grams processing were calculated by 1-d thermal model for a thin plate. Influence of uncertainty of experimental parameters, such as (radiation emission coefficients of sample surface, glue, temperature sensors and uncertainty of sensors placement on the result of defined thermal conductivity has been estimated. New data on the thermal conductivity in reinforcement plane were obtained within 295 - 375 K temperature range, which can be used to design and develop reflectors of precision space antennas. In the future it is expedient to conduct tests of thin-wall plates from carbon fiber-reinforced plastic in wide temperature range, especially in the low-range temperatures.

  9. Modeling reinforced concrete durability : [summary].

    Science.gov (United States)

    2014-06-01

    Many Florida bridges are built of steel-reinforced concrete. Floridas humid and marine : environments subject steel in these structures : to corrosion once water and salt penetrate the : concrete and contact the steel. Corroded steel : takes up mo...

  10. Evolutionary computation for reinforcement learning

    NARCIS (Netherlands)

    Whiteson, S.; Wiering, M.; van Otterlo, M.

    2012-01-01

    Algorithms for evolutionary computation, which simulate the process of natural selection to solve optimization problems, are an effective tool for discovering high-performing reinforcement-learning policies. Because they can automatically find good representations, handle continuous action spaces,

  11. Cranioplasty with individual carbon fibre reinforced polymere (CFRP) medical grade implants based on CAD/CAM technique.

    Science.gov (United States)

    Saringer, W; Nöbauer-Huhmann, I; Knosp, E

    2002-11-01

    The authors present a new method for the reconstruction of large or complex-formed cranial bone defects using prefabricated, computer-generated, individual CFRP (carbon fibre reinforced plastics) medical grade implants. CFRP is a composite material containing carbon fibres embedded in an epoxy resin matrix. It is radiolucent, heat-resistant, extremely strong and light (its weight is 20% that of steel), has a modulus of elasticity close to that of bone, and an established biocompatibility. The utilisation of a CAD/CAM (computer aided design/computer aided manufacture) technique based on digitised computed tomography (CT) data, with stereolithographic modelling as intermediate step, enabled the production of individual, prefabricated CFRP medical grade implants with an arithmetical maximum aberration in extension of less than +/-0.25 mm. Between 1995 and February 2002, 29 patients (15 men and 14 women; mean age, 39.9 years; range, 16 to 67 years) underwent cranioplasty with CFRP medical grade implants at the neurosurgical department of the University of Vienna. Twenty-four patients were repaired secondarily (delayed cranioplasty) while 5 were repaired immediately following craniectomy (single stage cranioplasty). All cases were assessed for the accuracy of the intra-operative fit of the implant, restoration of the natural skull contour and aesthetics and adverse symptoms. The intra-operative fit was excellent in 93.1% and good in 6.9% of the implants. In two cases minor adjustments of the bony margin of the defect were required. The operating time for insertion ranged from 16 to 38 minutes, median 21 minutes. Postoperatively, 86.2% of the patients graded the restoration of their natural skull shape and symmetry as excellent while 13.8% termed it good. In one patient a non-space occupying subdural hygroma was found at the follow-up, but required no intervention. Two patients experienced atrophy of the frontal portion of the temporal muscle while one patient had a

  12. Deep Reinforcement Learning: An Overview

    OpenAIRE

    Li, Yuxi

    2017-01-01

    We give an overview of recent exciting achievements of deep reinforcement learning (RL). We discuss six core elements, six important mechanisms, and twelve applications. We start with background of machine learning, deep learning and reinforcement learning. Next we discuss core RL elements, including value function, in particular, Deep Q-Network (DQN), policy, reward, model, planning, and exploration. After that, we discuss important mechanisms for RL, including attention and memory, unsuperv...

  13. The dorsal shell wall structure of Mesozoic ammonoids

    Directory of Open Access Journals (Sweden)

    Gregor Radtke

    2017-03-01

    Full Text Available The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic reduced dorsal shell wall which consists of an outer organic component (e.g., wrinkle layer, which is the first layer to be formed, and the subsequently formed dorsal inner prismatic layer. The dorsal mantle tissue suppresses the formation of the outer prismatic layer and nacreous layer. With the exception of the outer organic component, secretion of a shell wall is omitted at the aperture. A prismatic reduced dorsal shell wall is always secreted immediately after the hatching during early teleoconch formation. Due to its broad distribution in (planispiral Ammonoidea, the prismatic reduced dorsal shell wall is probably the general state. (ii Some planispirally coiled Ammonoidea have a nacreous reduced dorsal shell wall which consists of three mineralized layers: two prismatic layers (primary and secondary dorsal inner prismatic layer and an enclosed nacreous layer (secondary dorsal nacreous layer. The dorsal shell wall is omitted at the aperture and was secreted in the rear living chamber. Its layers are a continuation of an umbilical shell doubling (reinforcement by additional shell layers that extends towards the ventral crest of the preceding whorl. The nacreous reduced dorsal shell wall is formed in the process of ontogeny following a prismatic reduced dorsal shell wall. (iii Heteromorph and some planispirally coiled taxa secrete a complete dorsal shell wall which forms a continuation of the ventral and lateral shell layers. It is formed during ontogeny following a prismatic reduced dorsal shell wall or a priori. The construction is identical with the ventral and lateral shell wall, including a dorsal nacreous layer. The wide distribution of the ability to form dorsal nacre indicates that it is

  14. One-Piece Implant-Retained Mandibular Overdentures By Pre-Fabricated Titanium Telescopic Attachments and Frictional Varnish: A Two-Year Prospective Study.

    Science.gov (United States)

    Nik, Shahram Namjoy; Nejatian, Touraj

    2016-12-01

    Clinical efficiency of one-piece screw-type implants with telescopic were attachments evaluated in this study. Twenty-four patients received a mandibular implant-supported overdenture and maxillary complete denture. Ninety-six one-piece implants were inserted in the inter-foraminal area. Implants were immediately loaded with an implant-retained overdenture and telescopic attachments which had frictional retention elements. There was 0.25±0.24 mm, 0.32±0.25 mm, 0.43±0.30 mm, 0.61±0.30 mm and of bone resorption after 3, 6, 12 and 24 months, respectively. The need to activate the frictional retention was the most common complication. Treatment outcomes for prefabricated telescopic retained overdentures on one-piece implants are similar to that obtained in cases of delayed loading. Copyright© 2016 Dennis Barber Ltd.

  15. The influence of prefabricated pipe cement coatings and those made during pipe renovation on drinking water quality

    OpenAIRE

    Młyńska Anna; Zielina Michał

    2017-01-01

    Nowadays, cement coatings are often used as an anticorrosion protection of the internal surfaces of manufactured ductile iron water pipes. The protective cement linings are also commonly used for old water pipe renovation. In both cases, the cement lining is an excellent anticorrosion protection of the pipelines, effectively separating the pipe wall from the flowing water. Moreover, cement linings protect the pipelines not only by a mechanical barrier, but also by a chemical barrier creating ...

  16. Investigation of the mechanical properties of GNP/MWCNT reinforced PA66 hybrid nanocomposites

    DEFF Research Database (Denmark)

    Doagou Rad, Saeed; Islam, Aminul; Søndergaard Jensen, Jacob

    nanocomposites reinforced with two prominent nanofillers namely Multi Walled Carbon Nanotubes (MWCNT) and Graphene NanoPlatelets (GNP) manufactured through industrially viable methods. Three main groups of Polyamide (PA 66) based nano- and hybrid composite specimens namely PA 66/MWCNT, PA 66/GNP, and PA 66/MWCNT...

  17. Perbaikan Tanah Dasar Menggunakan Pre-Fabricated Vertical Drain Dengan Variasi Kedalaman Dan Perkuatan Lereng Dengan Turap Studi Kasus : Lapangan Penumpukan Peti Kemas, Pelabuhan Trisakti, Banjarmasin, Kalimantan Selatan

    Directory of Open Access Journals (Sweden)

    Dofran Winner

    2017-03-01

    Full Text Available Metode perbaikan tanah dasar menggunakan preloading yang dikombinasikan dengan Pre-fabricated Vertical Drain (PVD dipilih untuk proyek pengembangan lapangan penumpukan peti kemas di Pelabuhan Trisakti, Banjarmasin, Kalimantan Selatan. Selama masa preloading, ternyata kelongsoran selebar 37 meter terjadi di area penumpukan. Diketahui bahwa kelongsoran terjadi saat preloading setinggi 4,0 meter. Agar lapangan penumpukan dapat beroperasi kembali, diperlukan perencanaan untuk perkuatan lereng dan untuk menghilangkan pemampatan tanah dasar di area lapangan penumpukan. Perbaikan tanah dasar menggunakan preloading yang dikombinasikan dengan Pre-fabricated Vertical Drain (PVD digunakan untuk Zona 3, 4, dan 5, dan perkuatan lereng dengan turap digunakan untuk Zona-1 dan Zona-2 yang merupakan bagian lereng dari lapangan penumpukan. Direncanakan PVD dipasang pada kedalaman yang berbeda: 1/3H, 2/3H, dan H (H adalah ketebalan lapisan tanah lunak untuk melihat kondisi yang menghasilkan biaya paling murah. Dari hasil perencanaan yang dilakukan, diketahui bahwa turap yang digunakan adalah Corrugated Concrete sheet pile type W-600 A1000. Turap dipasang sedalam 18 meter di Zona-1 dan sedalam 22 meter di Zona-2; selain itu, angker dipasang pada turap untuk meningkatkan kekakuan turap. Hasil perencanaan juga menunjukkan bahwa biaya yang paling ekonomis adalah PVD dipasang sampai 2/3H di Zona-3, dan tanpa PVD di Zona-4 dan Zona-5. Total biaya konstruksi adalah sebesar Rp 843.106.053,00 untuk Zona-1 dan Zona-2; Rp 9.446.530.597,00 untuk Zona-3; Rp 1.869.613.200,00 untuk Zona 4; dan Rp 3.577.392.000,00 untuk Zona 5.

  18. The Analysis Stability of Anchor Retaining Wall

    International Nuclear Information System (INIS)

    Benamara, F. Z.; Belabed, L

    2011-01-01

    The construction of anchored retaining walls reach every day in the field of Civil Engineering especially in public works. Their dimensioning and stability are the axes of research for geotechnical. The rule is to reduce the active forces of the slide and increase the effective normal stress on the rupture surface. So that, we anchored tied-back (constituted by steel cables) in the stable ground located under the failure surface and we apply at the top a traction force. This effort can be distributed over the ground surface by means of small plates or massive reinforced concrete. The study of the stability of anchored retaining wall was also performed by using software GEO4. Many cases can be solved using analytical solutions available in the group GEO4 program, but for our standard model solution studied analytically proved unsatisfactory so we used a numerical analysis based on the method of finite element in this program. The results obtained by numerical study were interpreted to identify the precision numerical predictions. Moreover these methods were useful and economics in the realization of reinforced slopes by tied-buck. (author)

  19. BEHAVIOUR OF UNREINFORCED EXPANDED POLYSTYRENE LIGHTWEIGHT CONCRETE (EPS-LWC WALL PANEL ENHANCED WITH STEEL FIBRE

    Directory of Open Access Journals (Sweden)

    ROHANA MAMAT

    2015-12-01

    Full Text Available This study used steel fibre as reinforcement while enhancing the EPS-LWC strength. In line with architectural demand and ventilation requirement, opening within wall panel was also taken into account. Experimental tests were conducted for reinforced and unreinforced EPS-LWC wall panel. Two samples with size of 1500 mm (height x 1000 mm (length x 75 mm (thickness for each group of wall panel were prepared. Samples in each group had opening size of 600 mm (height x 400 mm (length located at 350 mm and 550 mm from upper end respectively. EPS-LWC wall panel had fcu of 20.87 N/mm2 and a density of 1900 kg/m3. The loading capacity, displacement profiles and crack pattern of each sample was analyzed and discussed. Unreinforced EPS-LWC enhanced with steel fibre resist almost similar loading as reinforced EPS-LWC wall panel. The presence of steel fibre as the only reinforcement creates higher lateral displacement. Wall panel experience shear failure at the side of opening. The number of micro cracks reduces significantly due to presence of steel fibre.

  20. Methods for producing reinforced carbon nanotubes

    Science.gov (United States)

    Ren, Zhifen [Newton, MA; Wen, Jian Guo [Newton, MA; Lao, Jing Y [Chestnut Hill, MA; Li, Wenzhi [Brookline, MA

    2008-10-28

    Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  1. Finite element analyses for Seismic Shear Wall International Standard Problem

    International Nuclear Information System (INIS)

    Park, Y.; Hofmayer, C.; Chokshi, N.

    1997-01-01

    In the seismic design of shear wall structures, e.g., nuclear reactor buildings, a linear FEM analysis is frequently used to quantify the stresses under the design loading condition. The final design decisions, however, are still based on empirical design rules established over decades from accumulated laboratory test data. This paper presents an overview of the state-of-the-art on the application of nonlinear FEM analysis to reinforced concrete (RC) shear wall structures under severe earthquake loadings based on the findings obtained during the Seismic Shear Wall International Standard Problem (SSWISP) Workshop in 1996. Also, BNL's analysis results of the International Standard Problem (ISP) shear walls under monotonic static, cyclic static and dynamic loading conditions are described

  2. Wall Finishes; Carpentry: 901895.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course outline is designed to provide instruction in selecting, preparing, and installing wall finishing materials. Prerequisites for the course include mastery of building construction plans, foundations and walls, and basic mathematics. Intended for use in grades 11 and 12, the course contains five blocks of study totaling 135 hours of…

  3. Wall Construction; Carpentry: 901892.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The curriculum guide outlines a course designed to provide instruction in floor and wall layout, and in the diverse methods and construction of walls. Upon completion of this course the students should have acquired a knowledge of construction plans and structural foundations in addition to a basic knowledge of mathematics. The course consists of…

  4. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, Lineke

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful,

  5. Supersymmetric domain walls

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kleinschmidt, Axel; Riccioni, Fabio

    2012-01-01

    We classify the half-supersymmetric "domain walls," i.e., branes of codimension one, in toroidally compactified IIA/IIB string theory and show to which gauged supergravity theory each of these domain walls belong. We use as input the requirement of supersymmetric Wess-Zumino terms, the properties of

  6. Steel fiber reinforced concrete behavior, modelling and design

    CERN Document Server

    Singh, Harvinder

    2017-01-01

    This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to d...

  7. Shear strength of reinforced concrete circular cross-section beams

    Directory of Open Access Journals (Sweden)

    P. W. G. N. Teixeira

    Full Text Available A proposed adequation of NBR 6118, Item 7.4, related to shear strength of reinforced concrete beams is presented with aims to application on circular cross-section. The actual expressions are most suitable to rectangular cross-section and some misleading occurs when applied to circular sections at determination of VRd2, Vc and Vsw, as consequence of bw (beam width and d (effective depth definitions as well as the real effectiveness of circular stirrups. The proposed adequation is based on extensive bibliographic review and practical experience with a great number of infrastructure elements, such as anchored retaining pile walls, where the use of circular reinforced concrete members is frequent.

  8. Solar Walls in tsbi3

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne

    tsbi3 is a user-friendly and flexible computer program, which provides support to the design team in the analysis of the indoor climate and the energy performance of buildings. The solar wall module gives tsbi3 the capability of simulating solar walls and their interaction with the building....... This version, C, of tsbi3 is capable of simulating five types of solar walls say: mass-walls, Trombe-walls, double Trombe-walls, internally ventilated walls and solar walls for preheating ventilation air. The user's guide gives a description of the capabilities and how to simulate solar walls in tsbi3....

  9. Corrosion of reinforcement bars in steel ibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe

    and the influence of steel fibres on initiation and propagation of cracks in concrete. Moreover, the impact of fibres on corrosion-induced cover cracking was covered. The impact of steel fibres on propagation of reinforcement corrosion was investigated through studies of their impact on the electrical resistivity...... of concrete, which is known to affect the corrosion process of embedded reinforcement. The work concerning the impact of steel fibres on initiation and propagation of cracks was linked to corrosion initiation and propagation of embedded reinforcement bars via additional studies. Cracks in the concrete cover...... are known to alter the ingress rate of depassivating substances and thereby influence the corrosion process. The Ph.D. study covered numerical as well as experimental studies. Electrochemically passive steel fibres are electrically isolating thus not changing the electrical resistivity of concrete, whereas...

  10. Evaluation of seismic shear capacity of prestressed concrete containment vessels with fiber reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Young Sun; Park, Jun Hee [Integrated Safety Assessment Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Fibers have been used in cement mixture to improve its toughness, ductility, and tensile strength, and to enhance the cracking and deformation characteristics of concrete structural members. The addition of fibers into conventional reinforced concrete can enhance the structural and functional performances of safety-related concrete structures in nuclear power plants. The effects of steel and polyamide fibers on the shear resisting capacity of a prestressed concrete containment vessel (PCCV) were investigated in this study. For a comparative evaluation between the shear performances of structural walls constructed with conventional concrete, steel fiber reinforced concrete, and polyamide fiber reinforced concrete, cyclic tests for wall specimens were conducted and hysteretic models were derived. The shear resisting capacity of a PCCV constructed with fiber reinforced concrete can be improved considerably. When steel fiber reinforced concrete contains hooked steel fibers in a volume fraction of 1.0%, the maximum lateral displacement of a PCCV can be improved by > 50%, in comparison with that of a conventional PCCV. When polyamide fiber reinforced concrete contains polyamide fibers in a volume fraction of 1.5%, the maximum lateral displacement of a PCCV can be enhanced by ∼40%. In particular, the energy dissipation capacity in a fiber reinforced PCCV can be enhanced by > 200%. The addition of fibers into conventional concrete increases the ductility and energy dissipation of wall structures significantly. Fibers can be effectively used to improve the structural performance of a PCCV subjected to strong ground motions. Steel fibers are more effective in enhancing the shear performance of a PCCV than polyamide fibers.

  11. Evaluation of seismic shear capacity of prestressed concrete containment vessels with fiber reinforcement

    International Nuclear Information System (INIS)

    Choun, Young Sun; Park, Jun Hee

    2015-01-01

    Fibers have been used in cement mixture to improve its toughness, ductility, and tensile strength, and to enhance the cracking and deformation characteristics of concrete structural members. The addition of fibers into conventional reinforced concrete can enhance the structural and functional performances of safety-related concrete structures in nuclear power plants. The effects of steel and polyamide fibers on the shear resisting capacity of a prestressed concrete containment vessel (PCCV) were investigated in this study. For a comparative evaluation between the shear performances of structural walls constructed with conventional concrete, steel fiber reinforced concrete, and polyamide fiber reinforced concrete, cyclic tests for wall specimens were conducted and hysteretic models were derived. The shear resisting capacity of a PCCV constructed with fiber reinforced concrete can be improved considerably. When steel fiber reinforced concrete contains hooked steel fibers in a volume fraction of 1.0%, the maximum lateral displacement of a PCCV can be improved by > 50%, in comparison with that of a conventional PCCV. When polyamide fiber reinforced concrete contains polyamide fibers in a volume fraction of 1.5%, the maximum lateral displacement of a PCCV can be enhanced by ∼40%. In particular, the energy dissipation capacity in a fiber reinforced PCCV can be enhanced by > 200%. The addition of fibers into conventional concrete increases the ductility and energy dissipation of wall structures significantly. Fibers can be effectively used to improve the structural performance of a PCCV subjected to strong ground motions. Steel fibers are more effective in enhancing the shear performance of a PCCV than polyamide fibers

  12. Effect of reinforcement with resin composite on fracture strength of structurally compromised roots.

    Science.gov (United States)

    Fukui, Yuji; Komada, Wataru; Yoshida, Keiichi; Otake, Shiho; Okada, Daizo; Miura, Hiroyuki

    2009-09-01

    This study was aimed at evaluating the fracture resistance of structurally compromised roots restored with four different post and core systems. Thirty-two bovine roots were uniformly shaped to simulate human mandibular premolar roots. The roots were divided into four groups based on the type of restoration: cemented cast post and core (Group MC), resin composite build-up (Group CR), resin composite and prefabricated glass fiber post build-up (Group FRC), and thick-layer dual-cured resin composite-reinforced small-diameter tapered cast post and core (Group CRM). After a static loading test, the failure mode and fracture resistance were recorded. Group CRM (719.38+/-196.73 N) exhibited a significantly high fracture resistance compared with the other groups (Group MC: 429.56+/-82.43 N; Group CR: 349.56+/-66.21 N; Group FRC: 398.94+/-112.71 N; pCRM exhibited better mechanical properties for structurally compromised roots with no ferrules, although all types of restorations showed non-restorable fracture modes.

  13. An overview of development and status of fiber-reinforced composites as dental and medical biomaterials.

    Science.gov (United States)

    Vallittu, Pekka K

    2018-01-01

    Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions.

  14. Observations on out-of-plane behaviour of URM walls in buildings with RC slabs

    OpenAIRE

    Tondelli, Marco; Beyer, Katrin

    2014-01-01

    In Switzerland many new residential buildings are constructed as unreinforced masonry (URM) structures or as mixed structures where URM walls are coupled with reinforced concrete (RC) walls by RC slabs. At present the boundary conditions of URM walls subjected to out-of-plane accelerations are still not well quantified. In the framework of a large research activity on RC-URM wall structures a shake-table test on a four-storey mixed structure was performed. The test specimen, which was built a...

  15. On the role of CFRP reinforcement for wood beams stiffness

    Science.gov (United States)

    Ianasi, A. C.

    2015-11-01

    In recent years, carbon fiber composites have been increasingly used in different ways in reinforcing structural elements. Specifically, the use of composite materials as a reinforcement for wood beams under bending loads requires paying attention to several aspects of the problem such as the number of the composite layers applied on the wood beams. Study consolidation of composites revealed that they are made by bonding fibrous material impregnated with resin on the surface of various elements, to restore or increase the load carrying capacity (bending, cutting, compression or torque) without significant damage of their rigidity. Fibers used in building applications can be fiberglass, aramid or carbon. Items that can be strengthened are concrete, brick, wood, steel and stone, and in terms of structural beams, walls, columns and floors. This paper describes an experimental study which was designed to evaluate the effect of composite material on the stiffness of the wood beams. It proposes a summary of the fundamental principles of analysis of composite materials and the design and use. The type of reinforcement used on the beams is the carbon fiber reinforced polymer (CFRP) sheet and plates and also an epoxy resin for bonding all the elements. Structural epoxy resins remain the primary choice of adhesive to form the bond to fiber-reinforced plastics and are the generally accepted adhesives in bonded CFRP-wood connections. The advantages of using epoxy resin in comparison to common wood-laminating adhesives are their gap-filling qualities and the low clamping pressures that are required to form the bond between carbon fiber plates or sheets and the wood beams. Mechanical tests performed on the reinforced wood beams showed that CFRP materials may produce flexural displacement and lifting increases of the beams. Observations of the experimental load-displacement relationships showed that bending strength increased for wood beams reinforced with CFRP composite plates

  16. Design of SC walls and slabs for impulsive loading

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Amit H. [Purdue Univ., West Lafayette, IN (United States)

    2015-11-11

    Reinforced concrete (RC) structures have historically been the preferred choice for blast resistant structures because of their mass and the ductility provided by steel reinforcement. Steel-plate composite (SC) walls are a viable alternative to RC for protecting the infrastructure against explosive threats. SC structures consist of two steel faceplates with a plain concrete core between them. The steel faceplates are anchored to the concrete using stud anchors and connected to each other using tie bars. SC structures provide mass from the concrete infill and ductility from the continuous external steel faceplates. This dissertation presents findings and recommendations from experimental and analytical investigations of the performance of SC walls subjected to far-field blast loads.

  17. Numerical simulation of a high velocity impact on fiber reinforced materials

    International Nuclear Information System (INIS)

    Thoma, Klaus; Vinckier, David

    1994-01-01

    Whereas the calculation of a high velocity impact on isotropical materials can be done on a routine basis, the simulation of the impact and penetration process into nonisotropical materials such as reinforced concrete or fiber reinforced materials still is a research task.We present the calculation of an impact of a metallic fragment on a modern protective wall structure. Such lightweight protective walls typically consist of two layers, a first outer layer made out of a material with high hardness and a backing layer. The materials for the backing layer are preferably fiber reinforced materials. Such types of walls offer a protection against fragments in a wide velocity range.For our calculations we used a non-linear finite element Lagrange code with explicit time integration. To be able to simulate the high velocity penetration process with a continuous erosion of the impacting metallic fragment, we used our newly developed contact algorithm with eroding surfaces. This contact algorithm is vectorized to a high degree and especially robust as it was developed to work for a wide range of contact-impact problems. To model the behavior of the fiber reinforced material under the highly dynamic loads, we present a material model which initially was developed to calculate the crash behavior (automotive applications) of modern high strength fiber-matrix systems. The model can describe the failure and the postfailure behavior up to complete material crushing.A detailed simulation shows the impact of a metallic fragment with a velocity of 750ms -1 on a protective wall with two layers, the deformation and erosion of fragment and wall material and the failure of the fiber reinforced material. ((orig.))

  18. Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

    Science.gov (United States)

    2018-01-01

    Corrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural ...

  19. Health monitoring of precast bridge deck panels reinforced with glass fiber reinforced polymer (GFRP) bars.

    Science.gov (United States)

    2012-03-01

    The present research project investigates monitoring concrete precast panels for bridge decks that are reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Due to the lack of long term research on concrete members reinforced with GFRP bars, lo...

  20. Leakproof Swaged Joints in Thin-Wall Tubing

    Science.gov (United States)

    Stuckenberg, F. H.; Crockett, L. K.; Snyder, W. E.

    1986-01-01

    Tubular inserts reinforce joints, reducing incidence of leaks. In new swaging technique, tubular inserts placed inside ends of both tubes to be joined. Made from thicker-wall tubing with outside diameter that matches inside diameter of thin tubing swaged, inserts support tube ends at joint. They ensure more uniform contact between swage fitting and tubing. New swaging technique developed for Al/Ti/V-alloy hydraulic supply lines.

  1. Plasma-wall interactions

    International Nuclear Information System (INIS)

    Behrisch, Rainer

    1978-01-01

    The plasma wall interactions for two extreme cases, the 'vacuum model' and the 'cold gas blanket' are outlined. As a first step for understanding the plasma wall interactions the elementary interaction processes at the first wall are identified. These are energetic ion and neutral particle trapping and release, ion and neutral backscattering, ion sputtering, desorption by ions, photons and electrons and evaporation. These processes have only recently been started to be investigated in the parameter range of interest for fusion research. The few measured data and their extrapolation into regions not yet investigated are reviewed

  2. Seismic performance evaluation of an infilled rocking wall frame structure through quasi-static cyclic testing

    Science.gov (United States)

    Pan, Peng; Wu, Shoujun; Wang, Haishen; Nie, Xin

    2018-04-01

    Earthquake investigations have illustrated that even code-compliant reinforced concrete frames may suffer from soft-story mechanism. This damage mode results in poor ductility and limited energy dissipation. Continuous components offer alternatives that may avoid such failures. A novel infilled rocking wall frame system is proposed that takes advantage of continuous component and rocking characteristics. Previous studies have investigated similar systems that combine a reinforced concrete frame and a wall with rocking behavior used. However, a large-scale experimental study of a reinforced concrete frame combined with a rocking wall has not been reported. In this study, a seismic performance evaluation of the newly proposed infilled rocking wall frame structure was conducted through quasi-static cyclic testing. Critical joints were designed and verified. Numerical models were established and calibrated to estimate frame shear forces. The results evaluation demonstrate that an infilled rocking wall frame can effectively avoid soft-story mechanisms. Capacity and initial stiffness are greatly improved and self-centering behavior is achieved with the help of the infilled rocking wall. Drift distribution becomes more uniform with height. Concrete cracks and damage occurs in desired areas. The infilled rocking wall frame offers a promising approach to achieving seismic resilience.

  3. The power reinforcement framework revisited

    DEFF Research Database (Denmark)

    Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.

    2016-01-01

    Whereas digital technologies are often depicted as being capable of disrupting long-standing power structures and facilitating new governance mechanisms, the power reinforcement framework suggests that information and communications technologies tend to strengthen existing power arrangements within...... public organizations. This article revisits the 30-yearold power reinforcement framework by means of an empirical analysis on the use of mobile technology in a large-scale programme in Danish public sector home care. It explores whether and to what extent administrative management has controlled decision......-making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert...

  4. The influence of prefabricated pipe cement coatings and those made during pipe renovation on drinking water quality

    Directory of Open Access Journals (Sweden)

    Młyńska Anna

    2017-01-01

    Full Text Available Nowadays, cement coatings are often used as an anticorrosion protection of the internal surfaces of manufactured ductile iron water pipes. The protective cement linings are also commonly used for old water pipe renovation. In both cases, the cement lining is an excellent anticorrosion protection of the pipelines, effectively separating the pipe wall from the flowing water. Moreover, cement linings protect the pipelines not only by a mechanical barrier, but also by a chemical barrier creating a highly alkaline environment in water contact with the metal pipe wall. In addition, cement coatings have an ability for so-called self-regeneration and provide the improvement of hydraulic conditions inside the pipelines. In turn, the differences between the analysed cement coatings mainly depend on the types of cements used and techniques of cement mortar spraying. As was expected, they influence the quality of water having contact with the coating. A comparison of the impact of cement coatings manufactured in factories and sprayed on building sites during the renovation on drinking water quality parameters was performed in the study. The experiments were conducted in laboratory conditions, using the test stands prepared for this purpose. The results include analysis of selected water quality parameters for the samples contacting with cement mortar and collected during the investigation.

  5. Advanced walling systems

    CSIR Research Space (South Africa)

    De Villiers, A

    2010-01-01

    Full Text Available The question addressed by this chapter is: How should advanced walling systems be planned, designed, built, refurbished, and end their useful lives, to classify as smart, sustainable, green or eco-building environments?...

  6. Fusion: first wall problems

    International Nuclear Information System (INIS)

    Behrisch, R.

    1976-01-01

    Some of the relevant elementary atomic processes which are expected to be of significance to the first wall of a fusion reactor are reviewed. Up to the present, most investigations have been performed at relatively high ion energies, typically E greater than 5 keV, and even in this range the available data are very poor. If the plasma wall interaction takes place at energies of E greater than 1 keV the impurity introduction and first wall erosion which will take place predominantly by sputtering, will be large and may severely limit the burning time of the plasma. The wall bombardment and surface erosion will presumably not decrease substantially by introducing a divertor. The erosion can only be kept low if the energy of the bombarding ions and neutrals can be kept below the threshold for sputtering of 1 to 10 eV. 93 refs

  7. First wall and divertor plate disposed facing to plasma of thermonuclear device

    International Nuclear Information System (INIS)

    Araki, Masanori; Suzuki, Satoshi; Akiba, Masato; Hayata, Yoshiho; Inoue, Taiji; Hayashi, Yukihiro; Kude, Yukinori

    1998-01-01

    In order to make the most of characteristics of each ingredient of carbon fiber-reinforced composite materials, carbon fiber unidirectionally reinforced materials and a carbon fiber three-directionally reinforced material are laminated in the direction of the thickness to form a carbon fiber-reinforced carbon composite material. In this case, the carbon fibers are continuously oriented in the direction of the thickness to constitute the carbon fiber reinforced carbon composite materials integrally. In addition, a carbon fiber-reinforced carbon composite material prepared by bonding a metal on one surface in adjacent with the unidirectional carbon fiber reinforced portion and substantially in perpendicular to the direction of the thickness of the unidirectional carbon fiber reinforced portion is used as a main constitutional material. Further, a metal tube is buried in the carbon fiber three-directionally reinforced carbon composite material. Then, a first wall and a divertor plate excellent in thermal impact resistance to be disposed facing to plasmas of a thermonuclear device can be provided. (N.H.)

  8. Cell Wall Metabolism in Response to Abiotic Stress

    Science.gov (United States)

    Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-01-01

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

  9. Plasma-wall interaction

    International Nuclear Information System (INIS)

    Reichle, R.

    2004-01-01

    This document gathers the 43 slides presented in the framework of the week long lecture 'hot plasmas 2004' and dedicated to plasma-wall interaction in a tokamak. This document is divided into 4 parts: 1) thermal load on the wall, power extraction and particle recovery, 2) basic edge plasma physics, 3) processes that drive the plasma-solid interaction, and 4) material conditioning (surface treatment...) for ITER

  10. Dynamic wall demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsui, L.; Mayhew, W.

    1990-12-01

    The dynamic wall concept is a ventilation strategy that can be applied to a single family dwelling. With suitable construction, outside air can be admitted through the exterior walls of the house to the interior space to function as ventilation air. The construction and performance monitoring of a demonstration house built to test the dynamic wall concept in Sherwood Park, Alberta, is described. The project had the objectives of demonstrating and assessing the construction methods; determining the cost-effectiveness of the concept in Alberta; analyzing the operation of the dynamic wall system; and determining how other components and systems in the house interact with the dynamic wall. The exterior wall construction consisted of vinyl siding, spun-bonded polyolefin-backed (SBPO) rigid fiberglass sheathing, 38 mm by 89 mm framing, fiberglass batt insulation and 12.7 mm drywall. The mechanical system was designed to operate in the dynamic (negative pressure) mode, however flexibility was provided to allow operation in the static (balanced pressure) mode to permit monitoring of the walls as if they were in a conventional house. The house was monitored by an extensive computerized monitoring system. Dynamic wall operation was dependent on pressure and temperature differentials between indoor and outdoor as well as wind speed and direction. The degree of heat gain was found to be ca 74% of the indoor-outdoor temperature differential. Temperature of incoming dynamic air was significantly affected by solar radiation and measurement of indoor air pollutants found no significant levels. 4 refs., 34 figs., 11 tabs.

  11. Orbital wall fractures

    International Nuclear Information System (INIS)

    Iinuma, Toshitaka; Ishio, Ken-ichirou; Yoshinami, Hiroyoshi; Kuriyama, Jun-ichi; Hirota, Yoshiharu.

    1993-01-01

    A total of 59 cases of mild facial fractures (simple orbital wall fractures, 34 cases, other facial fractures, 25 cases) with the clinical suspects of orbital wall fractures were evaluated both by conventional views (Waters' and Caldwell views) and coronal CT scans. Conventional views were obtained, as an average, after 4 days and CT after 7 days of injuries. Both the medial wall and the floor were evaluated at two sites, i.e., anterior and posterior. The ethmoid-maxillary plate was also included in the study. The degree of fractures was classified as, no fractures, fractures of discontinuity, dislocation and fragmentation. The coronal CT images in bone window condition was used as reference and the findings were compared between conventional views and CT. The correct diagnosis was obtained as follows: orbital floor (anterior, 78%, posterior, 73%), medial orbital wall (anterior, 72%, posterior, 72%) and ethmoid-maxillary plate (64%). The false positive diagnosis was as follows: orbital floor (anterior only, 13%), medial orbital wall (anterior only, 7%) and ethmoid-maxillary plate (11%). The false negative diagnosis was as follows: orbital floor (anterior, 9%, posterior, 10%), medial orbital wall (anterior, 21%, posterior, 28%) and ethmoid-maxillary plate (21%). The results were compared with those of others in the past. (author)

  12. Analysis of prestressed concrete wall segments

    International Nuclear Information System (INIS)

    Koziak, B.D.P.; Murray, D.W.

    1979-06-01

    An iterative numerical technique for analysing the biaxial response of reinforced and prestressed concrete wall segments subject to combinations of prestressing, creep, temperature and live loads is presented. Two concrete constitutive relations are available for this analysis. The first is a uniaxially bilinear model with a tension cut-off. The second is a nonlinear biaxial relation incorporating equivalent uniaxial strains to remove the Poissons's ratio effect under biaxial loading. Predictions from both the bilinear and nonlinear model are compared with observations from experimental wall segments tested in tension. The nonlinear model results are shown to be close to those of the test segments, while the bilinear results are good up to cracking. Further comparisons are made between the nonlinear analysis using constant membrane force-moment ratios, constant membrane force-curvature ratios, and a nonlinear finite difference analysis of a test containment structure. Neither nonlinear analysis could predict the reponse of every wall segment within the structure, but the constant membrane force-moment analysis provided lower bound results. (author)

  13. Performance of Screen Grid Insulating Concrete Form Walls under Combined In-Plane Vertical and Lateral Loads

    KAUST Repository

    Abdel Mooty, Mohamed

    2010-12-01

    Insulating Concrete Forms (ICF) walls generally comprise two layers of Expanded Polystyrene (EPS), steel reinforcement is placed in the center between the two layers and concrete is poured to fill the gap between those two layers. ICF\\'s have many advantages over traditional methods of wall construction such as reduced construction time, noise reduction, strength enhancement, energy efficiency, and compatibility with any inside or outside surface finish. The focus of this study is the Screen Grid ICF wall system consisting of a number of beams and columns forming a concrete mesh. The performance of ICF wall systems under lateral loads simulating seismic effect is experimentally evaluated in this paper. This work addresses the effect of the different design parameters on the wall behavior under seismic simulated loads. This includes different steel reinforcement ratio, various reinforcement distribution, wall aspect ratios, different openings sizes for windows and doors, as well as different spacing of the grid elements of the screen grid wall. Ten full scale wall specimens were tested where the effects of the various parameters on wall behavior in terms of lateral load capacity, lateral displacement, and modes of failure are presented. The test results are stored to be used for further analysis and calibration of numerical models developed for this study. © (2011) Trans Tech Publications.

  14. KETERASINGAN DALAM FILM WALL-E

    Directory of Open Access Journals (Sweden)

    Rahmadya Putra Nugraha

    2017-05-01

    Full Text Available Modern society nowadays technological advances at first create efficiency in human life. Further development of the technology thus drown human in a routine and automation of work created. The State is to be one of the causes of man separated from fellow or the outside world and eventually experiencing alienation. The movie as a mass media function to obtain the movie and entertainment can be informative or educative function is contained, even persuasive. The purpose of this research was conducted to find out the alienation in the movie Wall E. The concepts used to analyze the movie Wall E this is communication, movie, and alienation. The concept of alienation of human alienation from covering its own products of human alienation from its activities, the human alienation from nature of his humanity and human alienation from each other. Paradigm used is a critical paradigm with type a descriptive research with qualitative approach. The method used is the analysis of semiotics Roland Barthes to interpretation the scope of social alienation and fellow humans in the movie.This writing research results found that alienation of humans with other humans influenced the development of the technology and how the human it self represented of technology, not from our fellow human beings. Masyarakat modern saat ini kemajuan teknologi pada awalnya membuat efisiensi dalam kehidupan manusia. Perkembangan selanjutnya teknologi justru menenggelamkan manusia dalam suatu rutinitas dan otomatisasi kerja yang diciptakan. Keadaan itulah yang menjadi salah satu penyebab manusia terpisah dari sesama atau dunia luar dan akhirnya mengalami keterasingan. Film sebagai media massa berfungsi untuk memperoleh hiburan dan dalam film dapat terkandung fungsi informatif maupun edukatif, bahkan persuasif. Tujuan Penelitian ini dilakukan untuk mengetahui Keterasingan dalam film Wall E. Konsep-konsep yang digunakan untuk menganalisis film Wall E ini adalah komunikasi, film, dan

  15. Nanocellulose reinforcement of Transparent Composites

    Science.gov (United States)

    Joshua Steele; Hong Dong; James F. Snyder; Josh A. Orlicki; Richard S. Reiner; Alan W. Rudie

    2012-01-01

    In this work, we evaluate the impact of nanocellulose reinforcement on transparent composite properties. Due to the small diameter, high modulus, and high strength of cellulose nanocrystals, transparent composites that utilize these materials should show improvement in bulk mechanical performances without a corresponding reduction in optical properties. In this study...

  16. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...

  17. Reinforcement learning in supply chains.

    Science.gov (United States)

    Valluri, Annapurna; North, Michael J; Macal, Charles M

    2009-10-01

    Effective management of supply chains creates value and can strategically position companies. In practice, human beings have been found to be both surprisingly successful and disappointingly inept at managing supply chains. The related fields of cognitive psychology and artificial intelligence have postulated a variety of potential mechanisms to explain this behavior. One of the leading candidates is reinforcement learning. This paper applies agent-based modeling to investigate the comparative behavioral consequences of three simple reinforcement learning algorithms in a multi-stage supply chain. For the first time, our findings show that the specific algorithm that is employed can have dramatic effects on the results obtained. Reinforcement learning is found to be valuable in multi-stage supply chains with several learning agents, as independent agents can learn to coordinate their behavior. However, learning in multi-stage supply chains using these postulated approaches from cognitive psychology and artificial intelligence take extremely long time periods to achieve stability which raises questions about their ability to explain behavior in real supply chains. The fact that it takes thousands of periods for agents to learn in this simple multi-agent setting provides new evidence that real world decision makers are unlikely to be using strict reinforcement learning in practice.

  18. Stability of reinforced cemented backfills

    International Nuclear Information System (INIS)

    Mitchell, R.J.; Stone, D.M.

    1987-01-01

    Mining with backfill has been the subject of several international meetings in recent years and a considerable research effort is being applied to improve both mining economics and ore recovery by using backfill for ground support. Classified mill tailings sands are the most commonly used backfill material but these fine sands must be stabilized before full ore pillar recovery can be achieved. Normal portland cement is generally used for stabilization but the high cost of cement prohibits high cement usage. This paper considers the use of reinforcements in cemented fill to reduce the cement usage. It is concluded that strong cemented layers at typical spacings of about 3 meters in a low cement content bulk fill can reinforce the fill and reduce the overall cement usage. Fibre reinforcements introduced into strong layers or into bulk fills are also known to be effective in reducing cement usage. Some development work is needed to produce the ideal type of anchored fibre in order to realize economic gains from fibre-reinforced fills

  19. Adaptive representations for reinforcement learning

    NARCIS (Netherlands)

    Whiteson, S.

    2010-01-01

    This book presents new algorithms for reinforcement learning, a form of machine learning in which an autonomous agent seeks a control policy for a sequential decision task. Since current methods typically rely on manually designed solution representations, agents that automatically adapt their own

  20. Esthetic and Clinical Performance of Implant-Supported All-Ceramic Crowns Made with Prefabricated or CAD/CAM Zirconia Abutments: A Randomized, Multicenter Clinical Trial.

    Science.gov (United States)

    Wittneben, J G; Gavric, J; Belser, U C; Bornstein, M M; Joda, T; Chappuis, V; Sailer, I; Brägger, U

    2017-02-01

    Patients' esthetic expectations are increasing, and the options of the prosthetic pathways are currently evolving. The objective of this randomized multicenter clinical trial was to assess and compare the esthetic outcome and clinical performance of anterior maxillary all-ceramic implant crowns (ICs) based either on prefabricated zirconia abutments veneered with pressed ceramics or on CAD/CAM zirconia abutments veneered with hand buildup technique. The null hypothesis was that there is no statistically significant difference between the 2 groups. Forty implants were inserted in sites 14 to 24 (FDI) in 40 patients in 2 centers, the Universities of Bern and Geneva, Switzerland. After final impression, 20 patients were randomized into group A, restored with a 1-piece screw-retained single crown made of a prefabricated zirconia abutment with pressed ceramic as the veneering material using the cut-back technique, or group B using an individualized CAD/CAM zirconia abutment (CARES abutment; Institut Straumann AG) with a hand buildup technique. At baseline, 6 mo, and 1 y clinical, esthetic and radiographic parameters were assessed. Group A exhibited 1 dropout patient and 1 failure, resulting in a survival rate of 94.7% after 1 y, in comparison to 100% for group B. No other complications occurred. Clinical parameters presented stable and healthy peri-implant soft tissues. Overall, no or only minimal crestal bone changes were observed with a mean DIB (distance from the implant shoulder to the first bone-to-implant contact) of -0.15 mm (group A) and 0.12 mm (group B) at 1 y. There were no significant differences at baseline, 6 mo, and 1 y for DIB values between the 2 groups. Pink esthetic score (PES) and white esthetic score (WES) values at all 3 examinations indicated stability over time for both groups and pleasing esthetic outcomes. Both implant-supported prosthetic pathways represent a valuable treatment option for the restoration of single ICs in the anterior maxilla

  1. Colgajo prefabricado occipital para cobertura de exposición ósea craneal Prefabricated occipital flap to cover craneal bone exposition

    Directory of Open Access Journals (Sweden)

    B. Rivas León

    2010-03-01

    Full Text Available La exposición del cráneo tras un tratamiento quirúrgico oncológico agresivo es un desafió reconstructivo para el cirujano plástico; los defectos pueden variar en dimensiones y complejidad, desde pequeños defectos, que pueden ser cubiertos con injertos dérmicos o colgajos locales, a defectos más extensos que requerirán de un colgajo libre para su cobertura. Presentamos el caso de un varón de 39 años de edad que presentó un defecto biparietal posterior a radioterapia y resección por carcinoma. El defecto fue cubierto con un colgajo prefabricado axial, tomado del área antebraquial e implantado bajo la piel cabelluda occipital, para posteriormente ser llevado al sitio del defecto. El colgajo axial occipital evolucionó satisfactoriamente y logramos cubrir el defecto en su totalidad, sin complicaciones. En conclusión, el colgajo prefabricado occipital aporta suficiente piel cabelluda con patrón vascular axial para cubrir hueso craneal expuesto, cuando no hay una mejor opción cosmética.Cranial bone exposition after an aggressive oncological treatment is a challenge for plastic surgeon; defects can range in size and complexity, from small defects which can be covered only with skin graft or local flaps, to extensive defects that will require a free flap cover. We report a case of a 39 years-old man, who presented soft tissue defect of biparietal area following to radiotherapy and carcinoma resection. This defect was covered by prefabricated axial flap, which was harvest of forearm area and implanted under occipital hair skin and subsequently transported to the defect. The axial occipital flap healed uneventfully with a good outcome; we managed to cover the scalp defect completely without complications. As a conclusion, prefabricated occipital flap provides enough hair skin, with axial vascularity pattern to cover cranial bone exposed, when there is not a better cosmetical option.

  2. A protocol for a randomised controlled trial of prefabricated versus customised foot orthoses for people with rheumatoid arthritis: the FOCOS RA trial [Foot Orthoses - Customised v Off-the-Shelf in Rheumatoid Arthritis].

    Science.gov (United States)

    Gallagher, Kellie S; Godwin, Jon; Hendry, Gordon J; Steultjens, Martijn; Woodburn, Jim

    2018-01-01

    Foot pain is common in rheumatoid arthritis and appears to persist despite modern day medical management. Several clinical practice guidelines currently recommend the use of foot orthoses for the treatment of foot pain in people with rheumatoid arthritis. However, an evidence gap currently exists concerning the comparative clinical- and cost-effectiveness of prefabricated and customised foot orthoses in people with early rheumatoid arthritis. Early intervention with orthotics may offer the best opportunity for positive therapeutic outcomes. The primary aim of this study is to evaluate the comparative clinical- and cost-effectiveness of prefabricated versus customised orthoses for reducing foot pain over 12 months. This is a multi-centre two-arm parallel randomised controlled trial comparing prefabricated versus customised orthoses in participants with early rheumatoid arthritis (rheumatoid arthritis, global functional status via the Stanford Health Assessment Questionnaire, foot disease activity via the Rheumatoid Arthritis Foot Disease Activity Index, and health-related quality of life at baseline, 6 and 12 months. Process outcomes will include recruitment/retention rates, data completion rates, intervention adherence rates, and participant intervention and trial participation satisfaction. Cost-utility and cost-effectiveness analyses will be undertaken. Outcome measures collected at baseline, 6 and 12 months will be used to evaluate the comparative clinical- and cost- effectiveness of customised versus prefabricated orthoses for this treatment of early rheumatoid arthritis foot conditions. This trial will help to guide orthotic prescription recommendations for the management of foot pain for people with early rheumatoid arthritis in future. ISRCTN13654421. Registered 09 February 2016.

  3. Depression, Activity, and Evaluation of Reinforcement

    Science.gov (United States)

    Hammen, Constance L.; Glass, David R., Jr.

    1975-01-01

    This research attempted to find the causal relation between mood and level of reinforcement. An effort was made to learn what mood change might occur if depressed subjects increased their levels of participation in reinforcing activities. (Author/RK)

  4. Stripping demolition of concrete by applying electric current through reinforcing bars

    International Nuclear Information System (INIS)

    Nakagawa, Wahei; Kumegawa, Sadatsune

    1995-01-01

    The presence of reinforcing bars in reinforced concrete structures is an obstruction hindering the smooth progress of demolition works. The electric heating method is, on the other hand, a demolition technique of unique concept since it adopts the bars to help the demolition of reinforced concrete structures. This technique has the following advantages for demolition: 1) the more densely a structure is reinforced with bars, the greater is the effect of the electric heating, 2) demolition after heating produces little dust, and 3) electric heating of reinforcing bars causes no damage to the portions of concrete not subjected to electric current. The present paper describes the procedures and results of a series of experiments we conducted to verify the efficiency of the electric heating method. In this method, a low-voltage high-current is run through reinforcing bars existing in a concrete structure, inducing intense heat in the bars which in its turn brings about cracks in the surrounding concrete mass, facilitating secondary demolition by hammer picks or other means. The experiments were performed on full-scale biological shield wall mock-ups of a BWR and a small nuclear reactor. The experiments revealed that these excellent features of the electric heating method are worth utilizing in stripping demolition of radioactivated regions of biological shield walls in nuclear power plants. The electric heating method is currently being adopted and shows effective results in partial demolition works in diaphragm wall shafts where starting/arriving holes are to be fixed for shield machines without damaging surrounding portions. (author)

  5. Performance of Lightweight Natural-Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Hardjasaputra Harianto

    2017-01-01

    Full Text Available Concrete, the most common construction material, has negligible tension capacity. However, a reinforcement material such as natural fibers, can be used to improve the tensile properties of concrete. This paper presents experiments conducted on Super Lightweight Concrete mixed with coconut fibers (SLNFRC. Coconut fibers are regarded as one of the toughest natural fibers to strengthen concrete. Coconut fiber reinforced composites have been considered as a sustainable construction material because the fibers are derived from waste. These wastes, which are available in large quantities in Asia, have to be extracted from the husk of coconut fruits and must pass a mechanical process before being added to a concrete mixture. The Super Lightweight Concrete was made by mixing concrete paste with foam agent that can reduce the overall weight of concrete up to 60% with compressive strength up to 6 MPa. The Super Lightweight Concrete is intended to be used for non-structural walls, as alternative conventional construction materials such as brick walls. The influence of coconut fibers content in increasing the flexural tensile strength of Super Lightweight Concrete was studied in this research. The fiber content studied include 0%, 0.1%, 0.175%, and 0.25% by weight of cement content. Sixteen specimens of SLNFRC mini beams of 60 mm x 60 mm x 300 mm were tested to failure to investigate their flexural strengths. The optimum percent fibers yielding higher tensile strength was found to be 0.175%

  6. Rational and Mechanistic Perspectives on Reinforcement Learning

    Science.gov (United States)

    Chater, Nick

    2009-01-01

    This special issue describes important recent developments in applying reinforcement learning models to capture neural and cognitive function. But reinforcement learning, as a theoretical framework, can apply at two very different levels of description: "mechanistic" and "rational." Reinforcement learning is often viewed in mechanistic terms--as…

  7. Conditioned Reinforcement Value and Resistance to Change

    Science.gov (United States)

    Shahan, Timothy A.; Podlesnik, Christopher A.

    2008-01-01

    Three experiments examined the effects of conditioned reinforcement value and primary reinforcement rate on resistance to change using a multiple schedule of observing-response procedures with pigeons. In the absence of observing responses in both components, unsignaled periods of variable-interval (VI) schedule food reinforcement alternated with…

  8. Damage Model of Reinforced Concrete Members under Cyclic Loading

    Science.gov (United States)

    Wei, Bo Chen; Zhang, Jing Shu; Zhang, Yin Hua; Zhou, Jia Lai

    2018-06-01

    Based on the Kumar damage model, a new damage model for reinforced concrete members is established in this paper. According to the damage characteristics of reinforced concrete members subjected to cyclic loading, four judgment conditions for determining the rationality of damage models are put forward. An ideal damage index (D) is supposed to vary within a scale of zero (no damage) to one (collapse). D should be a monotone increasing function which tends to increase in the case of the same displacement amplitude. As for members under large displacement amplitude loading, the growth rate of D should be greater than that of D under small amplitude displacement loading. Subsequently, the Park-Ang damage model, the Niu-Ren damage model, the Lu-Wang damage model and the proposed damage model are analyzed for 30 experimental reinforced concrete members, including slabs, walls, beams and columns. The results show that current damage models do not fully matches the reasonable judgment conditions, but the proposed damage model does. Therefore, a conclusion can be drawn that the proposed damage model can be used for evaluating and predicting damage performance of RC members under cyclic loading.

  9. Study on the influence of Alkali-Silica reaction on structural behavior of reinforced concrete members

    International Nuclear Information System (INIS)

    Murazumi, Y.; Watanabe, Y.; Matsumoto, N.; Mitsugi, S.; Takiguchi, K.; Masuda, Y.

    2005-01-01

    Expansion produced by alkali-silica reaction (ASR) has been observed in the turbine generator foundation of the unit 1, Ikata nuclear power station, Japan. The foundation is a reinforced concrete frame structure. This paper, as a part of the series of investigation and experiments, discusses tests on structural behavior of concrete members affected by ASR. The purpose of the study is to obtain experimental results on the effects of ASR on bending and shear behavior of reinforced concrete beams and shear walls, and compare with the calculated results by present evaluation methods for normal concrete structures For the experiments on bending/shear behavior of beam, bending test models with a small amount of rebar and shear test models with larger amount were made of concrete in which ASR was induced by adding alkali or concrete without ASR. It was found from the results that bending strength of the bending test models and shear strength of the shear test models did not fall, nor was it lower than the calculated strength for concrete members without ASR. In the shear wall test, the two test models were made of either concrete with ASR or one without it. Horizontal load was applied with actuators on the test model fixed on the test floor, while vertical load was applied with oil jacks. The results did not indicate that ASR lowered the stiffness or strength of the wall test models, showing the strength was able to be calculated with the same formula for reinforced concrete wall without ASR. (authors)

  10. Stress Analysis for the Reinforcement of Concrete Massive Structures, Compatible with Building Methods

    OpenAIRE

    Mergny, Elke; Ansriou, M.; Lespagnard, A.; Ouaar, Amine; Latteur, Pierre; International Association for Shell and Spatial Structures (IASS) Symposium 2015

    2015-01-01

    - The wide majority of reinforced concrete structures are made of structural 1D or 2D elements such as beams, columns, slabs or walls, for which design methods are well known since decades, largely detailed in the literature such as EC2 or FIB Model Code [1, 2], and based on the fact that the knowledge of internal forces (moments, axial and shear forces) naturally lead to the values of the reinforcement. However, a minority of structures is characterized by a more or less complex three-dim...

  11. Kinetic wall from Israel

    Energy Technology Data Exchange (ETDEWEB)

    Godolphin, D.

    1985-05-01

    An unusual solar mass wall is described. At the turn of a handle it can change from a solar energy collector to a heat-blocker. An appropriate name for it might be the rotating prism wall. An example of the moving wall is at work in an adobe test home in Sede Boqer. Behind a large south-facing window stand four large adobe columns that are triangular in plan. One face of each of them is painted black to absorb sunlight, a second is covered with panels of polystyrene insulation, and a third is painted to match the room decor. These columns can rotate. On winter nights, the insulated side faces the glass, keeping heat losses down. The same scheme works in summer to keep heat out of the house. Small windows provide ventilation.

  12. Strengthening of Unreinforced Masonry Walls with Composite Materials

    Directory of Open Access Journals (Sweden)

    Ioana-Sorina Enţuc

    2004-01-01

    Full Text Available Unreinforced masonry (URM is considered one of the oldest construction materials being until the end of XIXth century, the basic material for: foundations, walls, columns, volts, staircases, floor joints, roofs, retaining walls, drainage channels, barrages, etc. Construction with URM elements posses a series of advantages such as: fire resistance, thermal an acoustic insulations between interior and outside spaces, humidity resistance. However the URM elements have some significant inconveniences such as: large self weight (heaviness causes cracks in the other elements of structures, reduced mechanical strengths in comparison with other traditional materials (steel and concrete, low tenacity, great manual labor consumptions, and vulnerability to earthquakes. Various factors cause deteriorations which must be overcome by strengthening solutions. Some strengthening solutions based on fiber reinforced polymers (FRP products applied directly on URM brick walls are presented in the paper.

  13. Seismic performance of geosynthetic-soil retaining wall structures

    Science.gov (United States)

    Zarnani, Saman

    Vertical inclusions of expanded polystyrene (EPS) placed behind rigid retaining walls were investigated as geofoam seismic buffers to reduce earthquake-induced loads. A numerical model was developed using the program FLAC and the model validated against 1-g shaking table test results of EPS geofoam seismic buffer models. Two constitutive models for the component materials were examined: elastic-perfectly plastic with Mohr-Coulomb (M-C) failure criterion and non-linear hysteresis damping model with equivalent linear method (ELM) approach. It was judged that the M-C model was sufficiently accurate for practical purposes. The mechanical property of interest to attenuate dynamic loads using a seismic buffer was the buffer stiffness defined as K = E/t (E = buffer elastic modulus, t = buffer thickness). For the range of parameters investigated in this study, K ≤50 MN/m3 was observed to be the practical range for the optimal design of these systems. Parametric numerical analyses were performed to generate design charts that can be used for the preliminary design of these systems. A new high capacity shaking table facility was constructed at RMC that can be used to study the seismic performance of earth structures. Reduced-scale models of geosynthetic reinforced soil (GRS) walls were built on this shaking table and then subjected to simulated earthquake loading conditions. In some shaking table tests, combined use of EPS geofoam and horizontal geosynthetic reinforcement layers was investigated. Numerical models were developed using program FLAC together with ELM and M-C constitutive models. Physical and numerical results were compared against predicted values using analysis methods found in the journal literature and in current North American design guidelines. The comparison shows that current Mononobe-Okabe (M-O) based analysis methods could not consistently satisfactorily predict measured reinforcement connection load distributions at all elevations under both static

  14. Effects of partial reinforcement and time between reinforced trials on terminal response rate in pigeon autoshaping.

    Science.gov (United States)

    Gottlieb, Daniel A

    2006-03-01

    Partial reinforcement often leads to asymptotically higher rates of responding and number of trials with a response than does continuous reinforcement in pigeon autoshaping. However, comparisons typically involve a partial reinforcement schedule that differs from the continuous reinforcement schedule in both time between reinforced trials and probability of reinforcement. Two experiments examined the relative contributions of these two manipulations to asymptotic response rate. Results suggest that the greater responding previously seen with partial reinforcement is primarily due to differential probability of reinforcement and not differential time between reinforced trials. Further, once established, differences in responding are resistant to a change in stimulus and contingency. Secondary response theories of autoshaped responding (theories that posit additional response-augmenting or response-attenuating mechanisms specific to partial or continuous reinforcement) cannot fully accommodate the current body of data. It is suggested that researchers who study pigeon autoshaping train animals on a common task prior to training them under different conditions.

  15. An experimental investigation for external RC shear wall applications

    Science.gov (United States)

    Kaltakci, M. Y.; Ozturk, M.; Arslan, M. H.

    2010-09-01

    The strength and rigidity of most reinforced concrete (RC) buildings in Turkey, which are frequently hit by destructive earthquakes, is not at a sufficient level. Therefore, the result of earthquakes is a significant loss of life and property. The strengthening method most commonly preferred for these type of RC buildings is the application of RC infilled walls (shear walls) in the frame openings of the building. However, since the whole building has to be emptied and additional heavy costs arise during this type of strengthening, users prefer not to strengthen their buildings despite the heavy risk they are exposed to. Therefore, it is necessary to develop easier-to-apply and more effective methods for the rapid strengthening of housing and the heavily-used public buildings which cannot be emptied during the strengthening process (such as hospitals and schools). This study empirically analyses the different methods of a new system which can meet this need. In this new system, named "external shear wall application", RC shear walls are applied on the external surface of the building, along the frame plane rather than in the building. To this end, 7 test samples in 1/2 and 1/3 geometrical scale were designed to analyse the efficiency of the strengthening technique where the shear wall leans on the frame from outside of the building (external shear wall application) and of the strengthening technique where a specific space is left between the frame and the external shear wall by using a coupling beam to connect elements (application of external shear wall with coupling beam). Test results showed that the maximum lateral load capacity, initial rigidity and energy dissipation behaviours of the samples strengthened with external shear wall were much better than those of the bare frames.

  16. An experimental investigation for external RC shear wall applications

    Directory of Open Access Journals (Sweden)

    M. Y. Kaltakci

    2010-09-01

    Full Text Available The strength and rigidity of most reinforced concrete (RC buildings in Turkey, which are frequently hit by destructive earthquakes, is not at a sufficient level. Therefore, the result of earthquakes is a significant loss of life and property. The strengthening method most commonly preferred for these type of RC buildings is the application of RC infilled walls (shear walls in the frame openings of the building. However, since the whole building has to be emptied and additional heavy costs arise during this type of strengthening, users prefer not to strengthen their buildings despite the heavy risk they are exposed to. Therefore, it is necessary to develop easier-to-apply and more effective methods for the rapid strengthening of housing and the heavily-used public buildings which cannot be emptied during the strengthening process (such as hospitals and schools. This study empirically analyses the different methods of a new system which can meet this need. In this new system, named "external shear wall application", RC shear walls are applied on the external surface of the building, along the frame plane rather than in the building. To this end, 7 test samples in 1/2 and 1/3 geometrical scale were designed to analyse the efficiency of the strengthening technique where the shear wall leans on the frame from outside of the building (external shear wall application and of the strengthening technique where a specific space is left between the frame and the external shear wall by using a coupling beam to connect elements (application of external shear wall with coupling beam. Test results showed that the maximum lateral load capacity, initial rigidity and energy dissipation behaviours of the samples strengthened with external shear wall were much better than those of the bare frames.

  17. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding....... It was found that the specific damages made to the vapour barrier as part of the test did not have any provable effect on the moisture content. In general elements with an intact vapour barrier did not show a critical moisture content at the wind barrier after four years of exposure....

  18. Linear motion feed through with thin wall rubber sealing element

    Science.gov (United States)

    Mikhailov, V. P.; Deulin, E. A.

    2017-07-01

    The patented linear motion feedthrough is based on elastic thin rubber walls usage being reinforced with analeptic string fixed in the middle part of the walls. The pneumatic or hydro actuators create linear movement of stock. The length of this movement is two times more the rubber wall length. This flexible wall is a sealing element of feedthrough. The main advantage of device is negligible resistance force that is less then mentioned one in sealing bellows that leads to positioning error decreasing. Nevertheless, the thin wall rubber sealing element (TRE) of the feedthrough is the main unreliable element that was the reason of this element longevity research. The theory and experimental results help to create equation for TRE longevity calculation under vacuum or extra high pressure difference action. The equation was used for TRE longevity determination for hydraulic or vacuum equipment realization also as it helps for gas flow being leaking through the cracks in thin walls of rubber sealing element of linear motion feedthrough calculation.

  19. Woodflour as Reinforcement of Polypropylene

    Directory of Open Access Journals (Sweden)

    José Cláudio Caraschi

    2002-10-01

    Full Text Available The effect of the filler content and size, as well as accelerated aging on the mechanical properties of polypropylene composites reinforced with woodflour (WF/PP were evaluated. The composites were prepared by the extrusion of polypropylene with woodflour (Pinus elliotti based on following ratios: 15, 25 and 40 wt% with two different granulometries. The specimens were injection molded according to ASTM standards. The composite properties did not show significant differences as a function of the filler granulometry. We also observed that by increasing the filler content, both the mechanical properties and the melt flow index (MFI decreased, and the elasticity modulus, hardness and density increased. Concerning the accelerated aging, the composite presented a reduction in tensile properties. The results showed that the composite properties are extremely favorable when compared to other commercial systems reinforced by inorganic fillers.

  20. Carbon fiber reinforced asphalt concrete

    International Nuclear Information System (INIS)

    Jahromi, Saeed G.

    2008-01-01

    Fibers are often used in the manufacture of other materials. For many years, they have been utilized extensively in numerous applications in civil engineering. Fiber-reinforcement refers to incorporating materials with desired properties within some other materials lacking those properties. Use of fibers is not a new phenomenon, as the technique of fiber-reinforced bitumen began early as 1950. In all industrialized countries today, nearly all concretes used in construction are reinforced. A multitude of fibers and fiber materials are being introduced in the market regularly. The present paper presents characteristics and properties of carbon fiber-reinforced asphalt mixtures, which improve the performance of pavements. To evaluate the effect of fiber contents on bituminous mixtures, laboratory investigations were carried out on the samples with and without fibers. During the course of this study, various tests were undertaken, applying Marshall Test indirect tensile test, creep test and resistance to fatigue cracking by using repeated load indirect tensile test. Carbon fiber exhibited consistency in results and as such it was observed that the addition of fiber does affect the properties of bituminous mixtures, i.e. an increase in its stability and decrease in the flow value as well as an increase in voids in the mix. Results indicate that fibers have the potential to resist structural distress in pavement, in the wake of growing traffic loads and thus improve fatigue by increasing resistance to cracks or permanent deformation. On the whole, the results show that the addition of carbon fiber will improve some of the mechanical properties like fatigue and deformation in the flexible pavement. (author)

  1. FRP reinforcement of timber structures

    OpenAIRE

    Schober, Kay-Uwe; Harte, Annette M.; Kliger, Robert; Jockwer, Robert; Xu, Qingfeng; Chen, Jian-Fei

    2015-01-01

    Timber engineering has advanced over recent decades to offer an alternative to traditional materials and methods. The bonding of fibre reinforced plastics (FRP) with adhesives to timber structures for repair and strengthening has many advantages. However, the lack of established design rules has strongly restrained the use of FRP strengthening in many situations, where these could be a preferable option to most traditional techniques. A significant body of research has been carried out in rec...

  2. Continuous carbon nanotube reinforced composites.

    Science.gov (United States)

    Ci, L; Suhr, J; Pushparaj, V; Zhang, X; Ajayan, P M

    2008-09-01

    Carbon nanotubes are considered short fibers, and polymer composites with nanotube fillers are always analogues of random, short fiber composites. The real structural carbon fiber composites, on the other hand, always contain carbon fiber reinforcements where fibers run continuously through the composite matrix. With the recent optimization in aligned nanotube growth, samples of nanotubes in macroscopic lengths have become available, and this allows the creation of composites that are similar to the continuous fiber composites with individual nanotubes running continuously through the composite body. This allows the proper utilization of the extreme high modulus and strength predicted for nanotubes in structural composites. Here, we fabricate such continuous nanotube polymer composites with continuous nanotube reinforcements and report that under compressive loadings, the nanotube composites can generate more than an order of magnitude improvement in the longitudinal modulus (up to 3,300%) as well as damping capability (up to 2,100%). It is also observed that composites with a random distribution of nanotubes of same length and similar filler fraction provide three times less effective reinforcement in composites.

  3. Mechanics of fiber reinforced materials

    Science.gov (United States)

    Sun, Huiyu

    This dissertation is dedicated to mechanics of fiber reinforced materials and the woven reinforcement and composed of four parts of research: analytical characterization of the interfaces in laminated composites; micromechanics of braided composites; shear deformation, and Poisson's ratios of woven fabric reinforcements. A new approach to evaluate the mechanical characteristics of interfaces between composite laminae based on a modified laminate theory is proposed. By including an interface as a special lamina termed the "bonding-layer" in the analysis, the mechanical properties of the interfaces are obtained. A numerical illustration is given. For micro-mechanical properties of three-dimensionally braided composite materials, a new method via homogenization theory and incompatible multivariable FEM is developed. Results from the hybrid stress element approach compare more favorably with the experimental data than other existing numerical methods widely used. To evaluate the shearing properties for woven fabrics, a new mechanical model is proposed during the initial slip region. Analytical results show that this model provides better agreement with the experiments for both the initial shear modulus and the slipping angle than the existing models. Finally, another mechanical model for a woven fabric made of extensible yarns is employed to calculate the fabric Poisson's ratios. Theoretical results are compared with the available experimental data. A thorough examination on the influences of various mechanical properties of yarns and structural parameters of fabrics on the Poisson's ratios of a woven fabric is given at the end.

  4. Reinforcement learning in computer vision

    Science.gov (United States)

    Bernstein, A. V.; Burnaev, E. V.

    2018-04-01

    Nowadays, machine learning has become one of the basic technologies used in solving various computer vision tasks such as feature detection, image segmentation, object recognition and tracking. In many applications, various complex systems such as robots are equipped with visual sensors from which they learn state of surrounding environment by solving corresponding computer vision tasks. Solutions of these tasks are used for making decisions about possible future actions. It is not surprising that when solving computer vision tasks we should take into account special aspects of their subsequent application in model-based predictive control. Reinforcement learning is one of modern machine learning technologies in which learning is carried out through interaction with the environment. In recent years, Reinforcement learning has been used both for solving such applied tasks as processing and analysis of visual information, and for solving specific computer vision problems such as filtering, extracting image features, localizing objects in scenes, and many others. The paper describes shortly the Reinforcement learning technology and its use for solving computer vision problems.

  5. FEM investigation of concrete silos damaged and reinforced externally with CFRP

    Science.gov (United States)

    Kermiche, Sihem; Boussaid, Ouzine; Redjel, Bachir; Amirat, Abdelaziz

    2018-03-01

    The present work investigates the reinforcement of concrete wheat-grain silos under initial damage. The reinforcement is achieved by mounting bands of carbon fiber reinforced polymer (CFRP) on the external walls of the silo. 4 modes of reinforcement are adapted according to the width of the band, the gap between two bands, the height of reinforcement and the number of layers achieved through banding. Analytical analyses were conducted using the Reimbert method and the Eurocode 1 Part 4 method, as well as numerically through the finite element software Abaqus. Results show that the normal pressure reaches a peak value when approaching the silo hopper. Initial damage in a concrete silo was first determined using a 3D geometrical model, while the damage analyses were conducted to optimize the CFRP reinforcement by mounting 2 CFRP bands close together above and below the cylinder-hopper joint. Increasing the number of banding layers could produce better performance as the damage was slightly decreased from 0.161 to 0.152 for 1 and 4 layers respectively.

  6. eWALL

    DEFF Research Database (Denmark)

    Kyriazakos, Sofoklis; Mihaylov, Mihail; Anggorojati, Bayu

    2016-01-01

    challenge with impact in multiple sectors. In this paper we present an innovative ICT solution, named eWALL, that aims to address these challenges by means of an advanced ICT infrastructure and home sensing environment; thus differentiating from existing eHealth and eCare solutions. The system of e...

  7. Abdominal wall surgery

    Science.gov (United States)

    ... as liposuction , which is another way to remove fat. But, abdominal wall surgery is sometimes combined with liposuction. ... from the middle and lower sections of your abdomen to make it firmer ... removes excess fat and skin (love handles) from the sides of ...

  8. Occupy Wall Street

    DEFF Research Database (Denmark)

    Jensen, Michael J.; Bang, Henrik

    2013-01-01

    This article analyzes the political form of Occupy Wall Street on Twitter. Drawing on evidence contained within the profiles of over 50,000 Twitter users, political identities of participants are characterized using natural language processing. The results find evidence of a traditional...

  9. Endometriosis Abdominal wall

    International Nuclear Information System (INIS)

    Alvarez, M.; Carriquiry, L.

    2003-01-01

    Endometriosis of abdominal wall is a rare entity wi ch frequently appears after gynecological surgery. Case history includes three cases of parietal endometriosis wi ch were treated in Maciel Hospital of Montevideo. The report refers to etiological diagnostic aspects and highlights the importance of total resection in order to achieve definitive healing

  10. Full-scale demonstration of EBS construction technology II. Design, manufacturing and transportation of pre-fabricated EBS module (PEM)

    International Nuclear Information System (INIS)

    Asano, Hidekazu; Toguri, Satohito; Iwata, Yumiko; Kawakami, Susumu; Nagasawa, Yuji; Yoshida, Takeshi

    2008-01-01

    PEM was investigated as a full-scale demonstration for the design, manufacturing and construction by using simulated buffer material and overpack in consideration of horizontal emplacement. Also near full-scale tests were conducted to examine the applicability of air-bearing system which can be used to transport a heavy load at the drift tunnel as for PEM. With regard to PEM casing, design requirements were selected from the viewpoints of EBS performance and operation safety issues. The construction procedure was examined in consideration of the shapes of buffer material, which are previously positioned inside the casing. And design procedure of the casing was also examined and presented. A full-scale PEM casing as a longitudinally two-part divided cylinder type with connection flanges was manufactured by using carbon steel plate. The wall thickness of this non-leak tight type PEM casing was evaluated its mechanical integrity by 2-dimensional stress analysis in consideration of the emplacement condition on the drift tunnel basement. Mechanical integrity of a percolated type casing was also examined its mechanical integrity. Air-bearing unit, which originally apply to a flat/smooth surface, was modified to fit a curved surface of the drift tunnel. Two units were aligned with two parallel lines, which estimate to be able to lift 12 tons, about two-fifth of the total weight of full scale PEM. On the conducted transportation tests of the air-bearing units, considering the surface roughness of the drift tunnel, especially for its unevenness, capability and availability of the run-over such gaps were investigated. And effect of covering sheets which can improve the gapped surface into relatively smooth was also examined by using several candidate materials. Through these tests, combination of the covering sheets and the maximum available height difference were evaluated and identified. Also the maximum traction force to toe the loading was measured to design the air

  11. Chronic Abdominal Wall Pain.

    Science.gov (United States)

    Koop, Herbert; Koprdova, Simona; Schürmann, Christine

    2016-01-29

    Chronic abdominal wall pain is a poorly recognized clinical problem despite being an important element in the differential diagnosis of abdominal pain. This review is based on pertinent articles that were retrieved by a selective search in PubMed and EMBASE employing the terms "abdominal wall pain" and "cutaneous nerve entrapment syndrome," as well as on the authors' clinical experience. In 2% to 3% of patients with chronic abdominal pain, the pain arises from the abdominal wall; in patients with previously diagnosed chronic abdominal pain who have no demonstrable pathological abnormality, this likelihood can rise as high as 30% . There have only been a small number of clinical trials of treatment for this condition. The diagnosis is made on clinical grounds, with the aid of Carnett's test. The characteristic clinical feature is strictly localized pain in the anterior abdominal wall, which is often mischaracterized as a "functional" complaint. In one study, injection of local anesthesia combined with steroids into the painful area was found to relieve pain for 4 weeks in 95% of patients. The injection of lidocaine alone brought about improvement in 83-91% of patients. Long-term pain relief ensued after a single lidocaine injection in 20-30% of patients, after repeated injections in 40-50% , and after combined lidocaine and steroid injections in up to 80% . Pain that persists despite these treatments can be treated with surgery (neurectomy). Chronic abdominal wall pain is easily diagnosed on physical examination and can often be rapidly treated. Any physician treating patients with abdominal pain should be aware of this condition. Further comparative treatment trials will be needed before a validated treatment algorithm can be established.

  12. Premolar Axial Wall Height Effect on CAD/CAM Crown Retention

    Science.gov (United States)

    2016-05-24

    OC axial wall height was required in a study that involved zirconia copings cemented on stainless steel dies. The results of this study reinforced...surface area was determined using a digital measuring microscope (Hirox). Scanned preparations (CEREC) were fitted with e.max CAD crowns and cemented ...Figure 14. RelyX Unicem Cementation

  13. Nonlinear seismic analysis of a thick-walled concrete canyon structure

    International Nuclear Information System (INIS)

    Winkel, B.V.; Wagenblast, G.R.

    1989-01-01

    Conventional linear seismic analyses of a thick-walled lightly reinforced concrete structure were found to grossly underestimate its seismic capacity. Reasonable estimates of the seismic capacity were obtained by performing approximate nonlinear spectrum analyses along with static collapse evaluations. A nonlinear time history analyses is planned as the final verification of seismic adequacy

  14. Test and Analysis of a New Ductile Shear Connection Design for RC Shear Walls

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

    2017-01-01

    -bar loops. Contrary to the classical shear connections, the planes of the U-bar loops are here parallel to the plane of the wall elements. This feature enables a construction-friendly installation of the elements without the risk of rebars clashing. The core of mortar inside each U-bar loop is reinforced...

  15. Evaluation of the Effect of Axial Wall Modification and Coping Design on the Retention of Cement-retained Implant-supported Crowns

    Science.gov (United States)

    Derafshi, Reza; Ahangari, Ahmad Hasan; Torabi, Kianoosh; Farzin, Mitra

    2015-01-01

    Background and aims. Because of compromised angulations of implants, the abutments are sometimes prepared. The purpose of this study was to investigate the effect of removing one wall of the implant abutment on the retention of cement-retained crowns. Materials and methods. Four prefabricated abutments were attached to analogues and embedded in acrylic resin blocks. The first abutment was left intact. Axial walls were partially removed from the remaining abutments to produce abutments with three walls. The screw access channel for the first and second abutments were completely filled with composite resin. For the third and fourth abutments, only partial filling was done. Wax-up models were made by CAD/CAM. Ten cast copings were fabricated for each abutment. The copings of fourth abutment had an extension into the screw access channel. Copings were cemented with Temp Bond. The castings were removed from the abutment using an Instron machine, and the peak removal force was recorded. A one-way ANOVA was used to test for a significant difference followed by the pairwise comparisons. Results. The abutments with opened screw access channel had a significantly higher retention than the two other abutments. The abutment with removed wall and no engagement into the hole by the castings exhibited the highest retention. Conclusion. Preserving the opening of screw access channel significantly increases the retention where one of the axial walls of implant abutments for cement-retained restorations is removed during preparation. PMID:25973152

  16. Wind tunnels with adapted walls for reducing wall interference

    Science.gov (United States)

    Ganzer, U.

    1979-01-01

    The basic principle of adaptable wind tunnel walls is explained. First results of an investigation carried out at the Aero-Space Institute of Berlin Technical University are presented for two dimensional flexible walls and a NACA 0012 airfoil. With five examples exhibiting very different flow conditions it is demonstrated that it is possible to reduce wall interference and to avoid blockage at transonic speeds by wall adaptation.

  17. Rising damp in building walls: the wall base ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, A.S.; Delgado, J.M.P.Q.; Freitas, V.P. de [Faculdade de Engenharia da Universidade do Porto, Laboratorio de Fisica das Construcoes (LFC), Departamento de Engenharia Civil, Porto (Portugal)

    2012-12-15

    This work intends to validate a new system for treating rising damp in historic buildings walls. The results of laboratory experiments show that an efficient way of treating rising damp is by ventilating the wall base, using the HUMIVENT technique. The analytical model presented describes very well the observed features of rising damp in walls, verified by laboratory tests, who contributed for a simple sizing of the wall base ventilation system that will be implemented in historic buildings. (orig.)

  18. Experimental Investigations on Axially and Eccentrically Loaded Masonry Walls

    Science.gov (United States)

    Keshava, Mangala; Raghunath, Seshagiri Rao

    2017-12-01

    In India, un-reinforced masonry walls are often used as main structural components in load bearing structures. Indian code on masonry accounts the reduction in strength of walls by using stress reduction factors in its design philosophy. This code was introduced in 1987 and reaffirmed in 1995. The present study investigates the use of these factors for south Indian masonry. Also, with the gaining popularity in block work construction, the aim of this study was to find out the suitability of these factors given in the Indian code to block work masonry. Normally, the load carrying capacity of masonry walls can be assessed in three ways, namely, (1) tests on masonry constituents, (2) tests on masonry prisms and (3) tests on full-scale wall specimens. Tests on bricks/blocks, cement-sand mortar, brick/block masonry prisms and 14 full-scale brick/block masonry walls formed the experimental investigation. The behavior of the walls was investigated under varying slenderness and eccentricity ratios. Hollow concrete blocks normally used as in-fill masonry can be considered as load bearing elements as its load carrying capacity was found to be high when compared to conventional brick masonry. Higher slenderness and eccentricity ratios drastically reduced the strength capacity of south Indian brick masonry walls. The reduction in strength due to slenderness and eccentricity is presented in the form of stress reduction factors in the Indian code. These factors obtained through experiments on eccentrically loaded brick masonry walls was lower while that of brick/block masonry under axial loads was higher than the values indicated in the Indian code. Also the reduction in strength is different for brick and block work masonry thus indicating the need for separate stress reduction factors for these two masonry materials.

  19. Experimental and numerical modeling of basalt textile reinforced mortar behavior under uniaxial tensile stress

    International Nuclear Information System (INIS)

    Larrinaga, Pello; Chastre, Carlos; Biscaia, Hugo C.; San-José, José T.

    2014-01-01

    Highlights: • Making more deepen the knowledge of textile reinforced mortar in tensile stress. • Analyzing the effect of the reinforcing ratio of the composite. • To compare results with Aveston–Cooper–Kelly theory. • To develop a numerical model based on a finite element code. • Considering the importance of the bond-slip law of the mortar-to-textile-interface. - Abstract: During the last years several projects and studies have improved the knowledge about textile reinforced mortar (TRM) technology. TRM has already been used in strengthening masonry and reinforced concrete structural elements such as walls, arches, columns and beams. This material is presented as a real alternative to the use of fiber-reinforced polymers (FRP) in situations where these composites have presented some drawbacks or their use is banned. Textile reinforced mortar show a complex mechanical behavior derived from the heterogeneity of the constituent materials. This paper aims to deepen the knowledge of this composite material in terms of tensile behavior. Following this scope, this paper presents an experimental campaign focused on thirty-one TRM specimens reinforced with four different reinforcing ratios. The results are analyzed and contrasted with two distinct models. (i) The Aveston–Cooper–Kelly theory (ACK) which is based on a tri-linear analytical approach; and (ii) a non-linear numerical simulation with a 3D finite element code. The finite element analysis (FEA) of the TRM tensile tests also showed no significant dependence on the basalt-to-mortar interface, i.e., the choice of a bond-slip curve in order to reproduce the bond stresses and slippages along the interface is irrelevant and it can be simply considered as rigid interface

  20. Seismic fragility of reinforced concrete structures and components for application to nuclear facilities

    International Nuclear Information System (INIS)

    Gergely, P.

    1984-09-01

    The failure and fragility analyses of reinforced concrete structures and elements in nuclear reactor facilities within the Seismic Safety Margins Research Program (SSMRP) at the Lawrence Livermore National Laboratory are evaluated. Uncertainties in material modeling, behavior of low shear walls, and seismic risk assessment for nonlinear response receive special attention. Problems with ductility-based spectral deamplification and prediction of the stiffness of reinforced concrete walls at low stress levels are examined. It is recommended to use relatively low damping values in connection with ductility-based response reductions. The study of static nonlinear force-deflection curves is advocated for better nonlinear dynamic response predictions. Several details of the seismic risk analysis of the Zion plant are also evaluated. 73 references