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Sample records for concrete masonry units

  1. Concrete Masonry Unit Walls Retrofitted with Elastomeric Systems for Blast Loads

    National Research Council Canada - National Science Library

    Johnson, C. F; Slawson, T. R; Cummins, T. K; Davis, J. L

    2004-01-01

    Concrete masonry units (CMU), commonly referred to as concrete blocks, are the most common construction material utilized throughout the United States and the world for exterior walls of conventional structures...

  2. Lightweight concrete masonry units based on processed granulate of corn cob as aggregate

    Directory of Open Access Journals (Sweden)

    Faustino, J.

    2015-06-01

    Full Text Available A research work was performed in order to assess the potential application of processed granulate of corn cob (PCC as an alternative lightweight aggregate for the manufacturing process of lightweight concrete masonry units (CMU. Therefore, CMU-PCC were prepared in a factory using a typical lightweight concrete mixture for non-structural purposes. Additionally, lightweight concrete masonry units based on a currently applied lightweight aggregate such as expanded clay (CMU-EC were also manufactured. An experimental work allowed achieving a set of results that suggest that the proposed building product presents interesting material properties within the masonry wall context. Therefore, this unit is promising for both interior and exterior applications. This conclusion is even more relevant considering that corn cob is an agricultural waste product.En este trabajo de investigación se evaluó la posible aplicación de granulado procesado de la mazorca de maiz como un árido ligero alternativo en el proceso de fabricación de unidades de mampostería de hormigón ligero. Con esta finalidad, se prepararon en una fábrica diversas unidades de mampostería no estructural con granulado procesado de la mazorca de maiz. Además, se fabricaran unidades de mampostería estándar de peso ligero basado en agregados de arcilla expandida. Este trabajo experimental permitió lograr un conjunto de resultados que sugieren que el producto de construcción propuesto presenta interesantes propiedades materiales en el contexto de la pared de mampostería. Por lo tanto, esta solución es prometedora tanto para aplicaciones interiores y exteriores. Esta conclusión es aún más relevante teniendo en cuenta que la mazorca de maíz es un producto de desecho agrícola.

  3. Analytical Predictions of Fragment Penetration through Hollow Concrete Masonry Units

    Directory of Open Access Journals (Sweden)

    David Bogosian

    2008-01-01

    Full Text Available Modeling steel casing fragment impacts on hollow CMU poses some problems, since the fragments will typically penetrate through the front face and may also penetrate the back face. Techniques are needed for predicting (a the size of the hole created by the penetration, (b the size of the annular region of damaged concrete around the hole, and (c the residual velocity of the fragment. A series of calculations using the AUTODYN code were performed to investigate the accuracy and reliability of the model. The model uses the smooth particle hydrodynamics (SPH approach to represent the CMU. A variety of steel fragment sizes were projected at a layer of CMU, and the resulting hole size, damage, and fragment residual velocity were tabulated. Results were validated against existing empirical relationships to insure the model's applicability, while additional analyses demonstrated trends and parametric sensitivity.

  4. Preparation and characterization of masonry units, lightweight concrete based and agro-industrial wastes: a review

    Science.gov (United States)

    Díaz-Fuentes, C. X.

    2013-11-01

    Discussion about the new composite materials that integrate agro industrial residues for the masonry unit's production, which are directed towards its implementation in projects of affordable housing, is a subject of interest to the public and productive sector of the country. For this reason, it presents a descriptive review of primary and secondary sources, which support the project under study. The methodology consisted in finding research articles in databases supported by the scientific community, which are ordered, integrated and prioritized, creating a matrix synthesis, which condensed the objectives, type of material, studied properties and main results found. It was found that the composite materials for masonry use mainly clay or cement as matrix and as reinforcement, agro waste like paper fibers, bamboo, rice husks, among others are used. Moreover, the properties that determine its potential use are low density, stress resistance and low thermal conductivity. Comparing the results with traditional specimens as the block of clay, concrete, adobe vs. experimental models made of the compounds analyzed, favorable results were obtained in the case of integrating waste materials into its composition, optimized their properties. Thus, science and architecture converge through recognition of the properties of materials that expand the alternatives of building spaces, economic and environmentally sustainable.

  5. Laboratory Characterization of White Masonry Concrete

    National Research Council Canada - National Science Library

    Williams, Erin M; Akers, Stephen A; Reed, Paul A

    2006-01-01

    ... to characterize the strength and constitutive property behavior of a white masonry concrete (WMC). Forty-four mechanical property tests consisting of two hydrostatic compression tests, four unconfined compression...

  6. State-of-the-Art Report on Fiber-Reinforced Lightweight Aggregate Concrete Masonry

    Directory of Open Access Journals (Sweden)

    Saul Rico

    2017-01-01

    Full Text Available Masonry construction is the most widely used building method in the world. Concrete masonry is relatively low in cost due to the vast availability of aggregates used within the production process. These aggregate materials are not always reliable for structural use. One of the principal issues associated with masonry is the brittleness of the unit. When subject to seismic loads, the brittleness of the masonry magnifies. In regions with high seismic activity and unspecified building codes or standards, masonry housing has developed into a death trap for countless individuals. A common approach concerning the issue associated with the brittle characteristic of masonry is addition of steel reinforcement. However, this can be expensive, highly dependent on skillfulness of labor, and particularly dependent on the quality of available steel. A proposed solution presented in this investigation consists of introducing steel fibers to the lightweight aggregate concrete masonry mix. Previous investigations in the field of lightweight aggregate fiber-reinforced concrete have shown an increase in flexural strength, toughness, and ductility. The outcome of this research project provides invaluable data for the production of a ductile masonry unit capable of withstanding seismic loads for prolonged periods.

  7. 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...... in this paper. The proposed strengthening technique aims at increasing the lateral strength of infilled RC frames and maintaining the integrity of masonry infills during loading, which is an important seismic parameter for these elements. Material tests were conducted first for ECC in order to assess its...

  8. 75 FR 60480 - Concrete and Masonry Construction; Extension of the Office of Management and Budget's (OMB...

    Science.gov (United States)

    2010-09-30

    ...] Concrete and Masonry Construction; Extension of the Office of Management and Budget's (OMB) Approval of... requirements specified in the Standard on Concrete and Masonry Construction (29 CFR part 1926, subpart Q..., screens or pumps used for concrete and masonry construction) specified by paragraphs 1926.702(a)(2), (j)(1...

  9. Ambient Cured Alkali Activated Flyash Masonry Units

    Science.gov (United States)

    Venugopal, K.; Radhakrishna; Sasalatti, Vinod M.

    2016-09-01

    Geopolymers belong to a category of non-conventional and non-Portland cement based cementitious binders which are produced using industrial by products like fly ash and ground granulated blast furnace slag (GGBFS). This paper reports on the development of geopolymer mortars for production of masonry units. The geopolymer mortars were prepared by mixing various by products with manufactured sand and a liquid mixture of sodium silicate and sodium hydroxide solutions. After curing at ambient conditions, the masonry units were tested for strength properties such as water absorption, initial rate of absorption, compression, shear- bond, and stress-strain behaviour etc. It was observed that the flexural strength of the blocks is more than 2 MPa and shear bond strength is more than 0.4MPa. It was found that the properties of geopolymer blocks were superior to the traditional masonry units. Hence they can be recommended for structural masonry.

  10. Cement treated recycled crushed concrete and masonry aggregates for pavements

    NARCIS (Netherlands)

    Xuan, D.X.

    2012-01-01

    This research is focusing on the characterization of the mechanical and deformation properties of cement treated mixtures made of recycled concrete and masonry aggregates (CTMiGr) in relation to their mixture variables. An extensive laboratory investigation was carried out, in which the mechanical

  11. Introduction to Concrete Masonry. Introduction to Construction Series. Instructor Edition.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This competency-based curriculum guide on the specialty area of concrete masonry is part of the Introduction to Construction series. The series is designed with the flexible training requirements of open shop contractors, preapprenticeship programs, multicraft high school programs, technology education programs, and cooperative education programs…

  12. Strength of masonry blocks made with recycled concrete aggregates

    Science.gov (United States)

    Matar, Pierre; Dalati, Rouba El

    The idea of recycling concrete of demolished buildings aims at preserving the environment. Indeed, the reuse of concrete as aggregate in new concrete mixes helped to reduce the expenses related to construction and demolition (C&D) waste management and, especially, to protect the environment by reducing the development rate of new quarries. This paper presents the results of an experimental study conducted on masonry blocks containing aggregates resulting from concrete recycling. The purpose of this study is to investigate the effect of recycled aggregates on compressive strength of concrete blocks. Tests were performed on series of concrete blocks: five series each made of different proportions of recycled aggregates, and one series of reference blocks exclusively composed of natural aggregates. Tests showed that using recycled aggregates with addition of cement allows the production of concrete blocks with compressive strengths comparable to those obtained on concrete blocks made exclusively of natural aggregates.

  13. Experimental evaluation of the prevention methods for the interface between masonry infill walls and concrete columns

    OpenAIRE

    Tramontin,A. P.; Moreno Junior,A. L.; Oliveira,C. R

    2013-01-01

    Cracks that form at the interfaces between masonry structures are common uncontrolled occurrences in buildings. Numerous methods have been proposed by the construction industry to address this problem. Cracks continuously form in the joints between concrete columns and masonry infill walls. In this study, the most common methods for preventing these types of cracks were evaluated in laboratory experiments. Column masonry models were constructed using different types of joints between concrete...

  14. THE EVOLUTION OF THE DESIGN AND CONSTRUCTION OF MASONRY BUILDINGS IN THE UNITED STATES

    OpenAIRE

    Richard E. Klingner

    2012-01-01

    In this paper, the process used to develop building codes in the United States of America (USA) is summarized, with emphasis on masonry. Masonry materials used in the USA are discussed. Types of masonry construction in the USA are reviewed, addressing historical as well as modern masonry. Current non-structural and structural applications of masonry in the USA are reviewed. Historical development of masonry codes in the USA is summarized, with emphasis on the current Masonry Standards Joi...

  15. Masonry. Teacher's Guide. Building Maintenance Units of Instruction.

    Science.gov (United States)

    Barnes, Bill

    This teaching guide on masonry building maintenance, one in a series of six publications designed for building maintenance instructors in Texas, is designed to give students an understanding of masonry construction. Introductory material provides teachers with information on use of the units of instruction and personalization and localization of…

  16. A new concept in preventing water leakage through single-wythe concrete masonry walls

    Energy Technology Data Exchange (ETDEWEB)

    Sauve, D.; Sroka, K.; Nmai, C.

    1999-07-01

    In this paper, the details of a unique patented, water-repellent concrete block design that prevents moisture that enters the core are from reaching interior surfaces are presented. The subject water leakage-controlling concrete masonry unit (WLC CMU) employs a three stage water leakage prevention process, as follows: (1) the use of water-repellent admixtures and performance-optimized mix designs to resist the passage of wind-driven rain through the block and mortar itself; (2) a horizontal beveled edge, and chamfered vertical sides of the block's face shell that provide improved access for proper joint tooling and facilities water drainage away from bed joint areas; and (3) a series of grooves and channels that prevent moisture migration across the block web surfaces, and directs it to the flawed courses where it can be effectively drained from the building envelope. Wind-driven rain tests performed by the National Concrete Masonry Association (NCMA) clearly showed the benefits of WLC CMU technology. Using identical materials, mix design, and block manufacturing equipment, a 99% reduction of moisture penetration to the core area was witnessed twice after 72 hours of ASTM E 514 testing.

  17. 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)

  18. Self healing phenomena in concretes and masonry mortars: A microscopic study

    NARCIS (Netherlands)

    Nijland, T.G.; Larbi, J.A.; Hees, R.P.J. van; Lubelli, B.A.; Rooij, M.R. de

    2007-01-01

    A microscopic survey of over 1000 of samples of concrete and masonry mortars from structures in the Netherlands shows that, in practice, self healing occurs in historic lime and lime – puzzolana mortars, in contrast to modern cement bound concretes and mortars. Self healing may be effected by the

  19. Structural pounding of concrete frame structure with masonry infill wall under seismic loading

    Science.gov (United States)

    Ismail, Rozaina; Hasnan, Mohd Hafizudin; Shamsudin, Nurhanis

    2017-10-01

    Structural pounding is additional problem than the other harmful damage that may occurs due to the earthquake vibrations. A lot of study has been made by past researcher but most of them did not include the walls. The infill masonry walls are rarely involved analysis of structural systems but it does contribute to earthquake response of the structures. In this research, a comparison between adjacent building of 10-storey and 7-storey concrete frame structure without of masonry infill walls and the same dynamic properties of buildings. The diagonal strut approach is adopted for modeling masonry infill walls. This research also focused on finding critical building separation in order to prevent the adjacent structures from pounding. LUSAS FEA v14.03 software has been used for modeling analyzing the behavior of structures due to seismic loading and the displacement each floor of the building has been taken in order to determine the critical separation distance between the buildings. From the analysis that has been done, it is found that masonry infill walls do affect the structures behavior under seismic load. Structures without masonry infill walls needs more distance between the structures to prevent structural pounding due to higher displacement of the buildings when it sways under seismic load compared to structures with masonry infill walls. This shows that contribution of masonry infill walls to the analysis of structures cannot be neglected.

  20. 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.

  1. Experimental evaluation of the prevention methods for the interface between masonry infill walls and concrete columns

    Directory of Open Access Journals (Sweden)

    A. P. Tramontin

    Full Text Available Cracks that form at the interfaces between masonry structures are common uncontrolled occurrences in buildings. Numerous methods have been proposed by the construction industry to address this problem. Cracks continuously form in the joints between concrete columns and masonry infill walls. In this study, the most common methods for preventing these types of cracks were evaluated in laboratory experiments. Column masonry models were constructed using different types of joints between concrete columns and masonry infill walls, such as steel bars and steel mesh. The efficiency of each type of joint method was evaluated by performing direct tensile tests (pullout tests on the models and monitoring the evolution of the crack opening in the joint between the column and wall, as a function of load applied to the model. The results from this study indicate that the model composed of "electrowelded wire mesh without steel angles" is the best model for controlling cracking in the joints between concrete columns and masonry infill walls.

  2. 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.)

  3. Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks.

    Science.gov (United States)

    Xiao, Zhao; Ling, Tung-Chai; Kou, Shi-Cong; Wang, Qingyuan; Poon, Chi-Sun

    2011-08-01

    Utilization of construction and demolition (C&D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However, the presence of large quantities of crushed clay brick in some the C&D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks

    International Nuclear Information System (INIS)

    Xiao Zhao; Ling, Tung-Chai; Kou, Shi-Cong; Wang Qingyuan; Poon, Chi-Sun

    2011-01-01

    Highlights: → Solved the scientific and technological challenges impeding use of waste rubble derived from earthquake, by providing an alternative solution of recycling the waste in moulded concrete block products. → Significant requirements for optimum integration on the utilization of the waste aggregates in the production of concrete blocks are investigated. → A thorough understanding of the mechanical properties of concrete blocks made with waste derived from earthquake is reported. - Abstract: Utilization of construction and demolition (C and D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However, the presence of large quantities of crushed clay brick in some the C and D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates.

  5. Masonry Procedures. Building Maintenance. Module V. Instructor's Guide.

    Science.gov (United States)

    Eck, Francis

    This curriculum guide, one of six modules keyed to the building maintenance competency profile developed by industry and education professionals, provides materials for a masonry procedures unit containing eight lessons. Lesson topics are masonry safety practices; set forms; mix concrete; patch and/or repair concrete; pour and finish concrete; mix…

  6. THE EVOLUTION OF THE DESIGN AND CONSTRUCTION OF MASONRY BUILDINGS IN THE UNITED STATES

    Directory of Open Access Journals (Sweden)

    Richard E. Klingner

    2012-12-01

    Full Text Available In this paper, the process used to develop building codes in the United States of America (USA is summarized, with emphasis on masonry. Masonry materials used in the USA are discussed. Types of masonry construction in the USA are reviewed, addressing historical as well as modern masonry. Current non-structural and structural applications of masonry in the USA are reviewed. Historical development of masonry codes in the USA is summarized, with emphasis on the current Masonry Standards Joint Committee (MSJC Code and Specification. Future trends in that document are predicted. The paper closes with a list of challenges to the masonry industry, and a list of focused research topics intended to meet those challenges.

  7. A new discrete-element approach for the assessment of the seismic resistance of composite reinforced concrete-masonry buildings

    International Nuclear Information System (INIS)

    Calio, I.; Cannizzaro, F.; Marletta, M.; Panto, B.; D'Amore, E.

    2008-01-01

    In the present study a new discrete-element approach for the evaluation of the seismic resistance of composite reinforced concrete-masonry structures is presented. In the proposed model, unreinforced masonry panels are modelled by means of two-dimensional discrete-elements, conceived by the authors for modelling masonry structures, whereas the reinforced concrete elements are modelled by lumped plasticity elements interacting with the masonry panels through nonlinear interface elements. The proposed procedure was adopted for the assessment of the seismic response of a case study confined-masonry building which was conceived to be a typical representative of a wide class of residential buildings designed to the requirements of the 1909 issue of the Italian seismic code and widely adopted in the aftermath of the 1908 earthquake for the reconstruction of the cities of Messina and Reggio Calabria

  8. Application of petrographic examination techniques to the assessment of fire-damaged concrete and masonry structures

    International Nuclear Information System (INIS)

    Ingham, Jeremy P.

    2009-01-01

    The number of building fires has doubled over the last 50 years. There has never been a greater need for structures to be assessed for fire damage to ensure safety and enable appropriate repairs to be planned. Fortunately, even after a severe fire, concrete and masonry structures are generally capable of being repaired rather than demolished. By allowing direct examination of microcracking and mineralogical changes, petrographic examination has become widely used to determine the depth of fire damage for reinforced concrete elements. Petrographic examination can also be applied to fire-damaged masonry structures built of materials such as stone, brick and mortar. Petrography can ensure accurate detection of damaged geomaterials, which provides cost savings during building repair and increased safety reassurance. This paper comprises a review of the role of petrography in fire damage assessments, drawing on a range of actual fire damage investigations.

  9. 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)

  10. Image-based method for monitoring of crack opening on masonry and concrete using Mobile Platform

    Directory of Open Access Journals (Sweden)

    A. P. Martins

    Full Text Available This paper proposes an automatic method based on the computing vision, implemented in a mobile platform, to inspect cracks in masonry and concrete. The developed algorithm for image processing performs this task from images of the cracks evolution. The contribution of this paper is the development of a mobile tool with quick response aiming to assist technicians in periodic visits when monitoring the crack opening in masonry and concrete. The obtained results show, successfully, the dimensional alterations of cracks detected by mobile phone in a faster and accurate way compared with the conventional measurement technique. Regardless the irregular shape of the cracks, the proposed method has the advantage of producing results statistically significant in measurement repetition by decreasing the subjectivity inherent to manual measurement technique.

  11. Properties Of Concrete And Masonry Blocks Made Of Locally ...

    African Journals Online (AJOL)

    The porosity and depth :Jf carbonation were also determined. The test results indicated that it is possible to produce all-light weight scoria aggregate concrete with a compressive strength as high as 28 MPa within the normal range of cement content and using ordinary Portland cement. Positive results were obtained when ...

  12. Innovative Retrofit Insulation Strategies for Concrete Masonry Foundations

    Energy Technology Data Exchange (ETDEWEB)

    Huelman, P. [NorthernSTAR, St. Paul, MN (United States); Goldberg, L. [NorthernSTAR, St. Paul, MN (United States); Jacobson, R. [NorthernSTAR, St. Paul, MN (United States)

    2015-05-01

    Basements in climates 6 and 7 can account for a fraction of a home's total heat loss when fully conditioned. Such foundations are a source of moisture, with convection in open block cavities redistributing water from the wall base, usually when heating. Even when block cavities are capped, the cold foundation concrete can act as a moisture source for wood rim joist components that are in contact with it. Because below-grade basements are increasingly used for habitable space, cold foundation walls pose challenges for moisture contribution, energy use, and occupant comfort.

  13. In-Plane Behaviour of a Reinforcement Concrete Frame with a Dry Stack Masonry Panel

    Science.gov (United States)

    Lin, Kun; Totoev, Yuri Zarevich; Liu, Hongjun; Guo, Tianyou

    2016-01-01

    In order to improve the energy dissipation of the masonry infilled frame structure while decreasing the stiffening and strengthening effects of the infill panels, a new dry stacked panel (DSP) semi-interlocking masonry (SIM) infill panel has been developed. In this paper, the material properties of DSP and a traditional unreinforced masonry (URM) panel have been evaluated experimentally. A series of cyclic tests were performed to investigate the cyclic behaviour of the reinforcement concrete (RC) frame with different infill panels. The failure modes, damage evolution, hysteretic behaviour, stiffness degradation and energy dissipation were compared and analysed. We concluded that DSP is capable of significantly improving the seismic energy dissipation due to its hysteretic behaviour when the frame is in elastic stage without increasing the stiffness of the frame. Therefore, DSP or SIM panels can be considered as frictional dampers. Based on the experimental results, the influence of DSP was examined. Using the parallel model, the hysteretic loops of DSP subjected to different load cases were achieved. The typical full hysteretic loop for DSP could be divided into three distinct stages of behaviour: packing stage, constant friction stage and equivalent strut stage. The connection between the panel and the frame had a great effect on the transferring of different mechanical stages. The constant friction stage was verified to provide substantial energy dissipation and benefits to the ductility of the structure, which, therefore, is suggested to be prolonged in reality. PMID:28787906

  14. In-Plane Behaviour of a Reinforcement Concrete Frame with a Dry Stack Masonry Panel

    Directory of Open Access Journals (Sweden)

    Kun Lin

    2016-02-01

    Full Text Available In order to improve the energy dissipation of the masonry infilled frame structure while decreasing the stiffening and strengthening effects of the infill panels, a new dry stacked panel (DSP semi-interlocking masonry (SIM infill panel has been developed. In this paper, the material properties of DSP and a traditional unreinforced masonry (URM panel have been evaluated experimentally. A series of cyclic tests were performed to investigate the cyclic behaviour of the reinforcement concrete (RC frame with different infill panels. The failure modes, damage evolution, hysteretic behaviour, stiffness degradation and energy dissipation were compared and analysed. We concluded that DSP is capable of significantly improving the seismic energy dissipation due to its hysteretic behaviour when the frame is in elastic stage without increasing the stiffness of the frame. Therefore, DSP or SIM panels can be considered as frictional dampers. Based on the experimental results, the influence of DSP was examined. Using the parallel model, the hysteretic loops of DSP subjected to different load cases were achieved. The typical full hysteretic loop for DSP could be divided into three distinct stages of behaviour: packing stage, constant friction stage and equivalent strut stage. The connection between the panel and the frame had a great effect on the transferring of different mechanical stages. The constant friction stage was verified to provide substantial energy dissipation and benefits to the ductility of the structure, which, therefore, is suggested to be prolonged in reality.

  15. Innovative Retrofit Insulation Strategies for Concrete Masonry Foundations

    Energy Technology Data Exchange (ETDEWEB)

    Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Goldberg, L. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Jacobson, R. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2015-05-06

    This study was designed to test a new approach for foundation insulation retrofits, with the goal of demonstrating improved moisture control, improved occupant comfort, and reduced heat loss. Because conducting experimental research on existing below-grade assemblies is very difficult, most of the results are based on simulations. The retrofit approach consists of filling open concrete block cores with an insulating material and adding R-10 exterior insulation that extends 1 ft below grade. The core fill is designed to improve the R-value of the foundation wall and increase the interior wall surface temperature, but more importantly to block convection currents that could otherwise increase moisture loads on the foundation wall and interior space. The exterior insulation significantly reduces heat loss through the most exposed part of the foundation and further increases the interior wall surface temperature. This improves occupant comfort and decreases the risk of condensation. Such an insulation package avoids the full-depth excavation necessary for exterior insulation retrofits, reduces costs, and eliminates the moisture and indoor air quality risks associated with interior insulation retrofits. Retrofit costs for the proposed approach were estimated at roughly half those of a full-depth exterior insulation retrofit.

  16. Study of the block/grout interface in concrete and clay block masonry structures

    Directory of Open Access Journals (Sweden)

    O. S. Izquierdo

    Full Text Available ABSTRACT This work aims to study the behavior of the block/grout interface for concrete and clay block masonry. This was achieved by push-out and pull-out experimental tests including reinforcement bar in the latter one. The experimental result showed that there is a good bond between the concrete blocks internal faces and the grout, enough to prevent infill-slippage, and that the whole tensile strength of the usual reinforcement bars is achieved provided they are properly anchored. Nevertheless, for clay blocks there is a low bond between the clay blocks internal faces and the grout, allowing the infill-slippage before the reinforcement bars reach their yield stress.

  17. Axial compression behavior of concrete masonry wallettes strengthened with cement mortar overlays

    Directory of Open Access Journals (Sweden)

    F. L. De Oliveira

    Full Text Available This paper presents the results of a series of axial compression tests on concrete block wallettes coated with cement mortar overlays. Different types of mortars and combinations with steel welded meshes and fibers were tested. The experimental results were discussed based on different theoretical approaches: analytical and Finite Element Method models. The main conclusions are: a the application of mortar overlays increases the wall strength, but not in a uniform manner; b the strengthening efficiency of wallettes loaded in axial compression is not proportional to the overlay mortar strength because it can be affected by the failure mechanisms of the wall; c steel mesh reinforced overlays in combination with high strength mortar show better efficiency, because the steel mesh mitigates the damage effects in the block wall and in the overlays themselves; d simplified theoretical methods of analysis as described in this paper can give satisfactory predictions of masonry wall behavior up to a certain level.

  18. Experimental Study on a Self-Centering Earthquake-Resistant Masonry Pier with a Structural Concrete Column

    Directory of Open Access Journals (Sweden)

    Lijun Niu

    2017-01-01

    Full Text Available This paper proposes a slotting construction strategy to avoid shear behavior of multistory masonry buildings. The aspect ratio of masonry piers increases via slotting between spandrels and piers, so that the limit state of piers under an earthquake may be altered from shear to rocking. Rocking piers with a structural concrete column (SCC form a self-centering earthquake-resistant system. The in-plane lateral rocking behavior of masonry piers subjected to an axial force is predicted, and an experimental study is conducted on two full-scale masonry piers with an SCC, which consist of a slotting pier and an original pier. Meanwhile, a comparison of the rocking modes of masonry piers with an SCC and without an SCC was conducted in the paper. Experimental verification indicates that the slotting strategy achieves a change of failure modes from shear to rocking, and this resistant system with an SCC incorporates the self-centering and high energy dissipation properties. For the slotting pier, a lateral story drift ratio of 2.5% and a high displacement ductility of approximately 9.7 are obtained in the test, although the lateral strength decreased by 22.3% after slotting. The predicted lateral strength of the rocking pier with an SCC has a margin of error of 5.3%.

  19. Coda Wave Interferometry Method Applied in Structural Monitoring to Assess Damage Evolution in Masonry and Concrete Structures

    International Nuclear Information System (INIS)

    Masera, D; Bocca, P; Grazzini, A

    2011-01-01

    In this experimental program the main goal is to monitor the damage evolution in masonry and concrete structures by Acoustic Emission (AE) signal analysis applying a well-know seismic method. For this reason the concept of the coda wave interferometry is applied to AE signal recorded during the tests. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced masonry walls under variable amplitude loading and strengthening reinforced concrete (RC) beams under monotonic static load has been carried out. In the reinforced masonry wall, cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of masonry under static long-time loading. During the tests, the evaluation of fracture growth is monitored by coda wave interferometry which represents a novel approach in structural monitoring based on AE relative change velocity of coda signal. In general, the sensitivity of coda waves has been used to estimate velocity changes in fault zones, in volcanoes, in a mining environment, and in ultrasound experiments. This method uses multiple scattered waves, which travelled through the material along numerous paths, to infer tiny temporal changes in the wave velocity. The applied method has the potential to be used as a 'damage-gauge' for monitoring velocity changes as a sign of damage evolution into masonry and concrete structures.

  20. Design and performance of masonry mortars made with recycled concrete aggregates

    Directory of Open Access Journals (Sweden)

    Frías, M.

    2009-07-01

    Full Text Available The present paper discusses the technical feasibility ofusing the fine fraction of recycled aggregate fromconcrete rubble to manufacture cement mortar andpossible conditions.An initial study of the chemical and physical-mechanicalcharacteristics of fines recycled from selected concreteshowed that their high absorptivity and high sulfatecontent compared to natural limestone sands were thelimiting factors to their in masonry mortars.As in the caseof structural concrete, a blend of recycled and naturalaggregate would appear to be suitable for masonrymortars.A study of the mix proportions and characteristics ofmortars made with recycled concrete aggregate showedthat up to 25% recycled aggregate can be used incement-based masonry mortars with no significant declinein performance and no new admixtures or higher cementcontent requires.El presente trabajo presenta y discute las condiciones de viabilidad técnica para la utilización de la fracción fina de áridos reciclados, procedentes de escombro de hormigón, en la fabricación de morteros de albañilería utilizando cemento como conglomerante.Inicialmente, se estudian las características químicas y físico- mecánicas de los áridos reciclados finos procedentes de hormigón seleccionado. Se concluye que las características limitantes del árido reciclado para su uso en morteros de albañilería resultan ser la alta absorción y el elevado contenido en sulfatos, en comparación con las arenas naturales de naturaleza caliza. De forma análoga a lo recomendado en el hormigón estructural, se apunta hacia la utilización de mezclas de áridos reciclados y naturales en la fabricación de morteros de albañilería.Del estudio de dosificaciones y caracterización de morteros, elaborados con áridos reciclados de hormigón, se establece que los morteros de albañilería base cemento pueden incorporar un 25% como máximo de árido reciclado sin evidenciar pérdidas significativas de prestaciones. Y, no

  1. Nonlinear Modeling of Autoclaved Aerated Concrete Masonry Wall Strengthened using Ferrocement Sandwich Structure

    KAUST Repository

    M., Abdel-Mooty

    2011-01-01

    Autoclaved Aerated Concrete (AAC) block are used mainly as non-load-bearing walls that provide heat insulation. This results in considerable saving in cooling energy particularly in hot desert environment with large variation of daily and seasonal temperatures. However, due to the relatively low strength there use load bearing walls is limited to single storey and low-rise construction. A system to enhance the strength of the AAC masonry wall in resisting both inplane vertical and combined vertical and lateral loads using ferrocement technology is proposed in this research. The proposed system significantly enhances the load carrying capacity and stiffness of the AAC wall without affecting its insulation characteristics. Ferrocement is made of cement mortar reinforced with closely spaced wire mesh. Full scale wall specimens with height of 2100mm and width of 1820mm were tested with different configuration of ferrocement. A finite elementmodel is developed and verified against the experimentalwork. The results of the finite element model correlates well with the experimental results.

  2. Fatigue of Concrete Armour Units

    DEFF Research Database (Denmark)

    Sørensen, N. B.; Burcharth, H. F.; Liu, Z.

    1995-01-01

    In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed.......In the present article fatigue as a possible reason for failure of Dolosse armour units made of plain concrete is discussed....

  3. Laboratory evaluation to reduce respirable crystalline silica dust when cutting concrete roofing tiles using a masonry saw.

    Science.gov (United States)

    Carlo, Rebecca V; Sheehy, John; Feng, H Amy; Sieber, William K

    2010-04-01

    Respirable crystalline silica dust exposure in residential roofers is a recognized hazard resulting from cutting concrete roofing tiles. Roofers cutting tiles using masonry saws can be exposed to high concentrations of respirable dust. Silica exposures remain a serious threat for nearly two million U.S. construction workers. Although it is well established that respiratory diseases associated with exposure to silica dust are preventable, they continue to occur and cause disability or death. The effectiveness of both a commercially available local exhaust ventilation (LEV) system and a water suppression system in reducing silica dust was evaluated separately. The LEV system exhausted 0.24, 0.13, or 0.12 m(3)/sec of dust laden air, while the water suppression system supplied 0.13, 0.06, 0.03, or 0.02 L/sec of water to the saw blade. Using a randomized block design, implemented under laboratory conditions, the aforementioned conditions were evaluated independently on two types of concrete roofing tiles (s-shape and flat) using the same saw and blade. Each engineering control (LEV or water suppression) was replicated eight times, or four times for each type of tile. Analysis of variance was performed by comparing the mean airborne respirable dust concentrations generated during each run and engineering control treatment. The use of water controls and ventilation controls compared with the "no control" treatment resulted in a statistically significant (p tile cut. The percent reduction for respirable dust concentrations was 99% for the water control and 91% for the LEV. Results suggest that water is an effective method for reducing crystalline silica exposures. However, water damage potential, surface discolorations, cleanup, slip hazards, and other requirements may make the use of water problematic in many situations. Concerns with implementing an LEV system to control silica dust exposures include sufficient capture velocity, additional weight of the saw with the LEV

  4. 29 CFR 1926.704 - Requirements for precast concrete.

    Science.gov (United States)

    2010-07-01

    ..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural framing...

  5. Use of Metakaolin with stabilised extruded earth masonry units

    OpenAIRE

    Maskell, Daniel; Heath, Andrew; Walker, Pete

    2015-01-01

    Modern earth masonry increasingly utilises conventional methods of extruded fired brick production for the manufacture of unfired earth bricks. However, these bricks are not generally recommended for structural applications due to their loss of strength under elevated moisture contents. Disproportionate collapse could occur following accidental or intentional wetting of a 100mm thick load bearing unfired earth wall. Unfired clay bricks can be chemically stabilised, typically by the addition o...

  6. Study of the Arrangement Effect of Units on the Shear Strength Masonry Walls in Meso-Scale

    Directory of Open Access Journals (Sweden)

    M. Sepehrinia

    2016-12-01

    Full Text Available Masonry is one of the oldest building materials which have been used in most heritage structures and new construction. In this study by using a meso-scale finite element model, the behavior of masonry walls is investigated under monotonic loading by Abaqus software. The most important factor in determining the behavior of masonry structures is discontinuity joints which are interface between unit and mortar. In most previous studies cohesive element is used for modeling of interface element. But in this study, by ignoring cohesive elements that represents the interface element between unit and mortar in masonry structures, it can be seen that while reducing the computational requirements, the results are in good agreement with experimental studies. Another important factor in the behavior of masonry walls is the arrangement of masonry units. In this study the overlapping effect of rows of units on the shear strength and failure mode of masonry walls have been investigated. As a result, it was observed that by increasing overlap, shear resistance of masonry walls increased.

  7. A proposal for the maximum use of recycled concrete sand in masonry mortar design

    Directory of Open Access Journals (Sweden)

    Fernández-Ledesma, E.

    2016-03-01

    Full Text Available Natural sand mining from rivers and seashores is causing serious environmental problems in many parts of the world, whereas the fine fraction from recycling concrete waste is underutilized as a construction material. The aim of this paper is to determine the maximum replacement level of natural sand by recycled sand in the manufacturing of masonry mortar (M-10. For this purpose, five replacement levels were tested: 0%, 25%, 50%, 75% and 100% by volume. The mixes were made using cement CEM II/BL 32.5 N in a volumetric proportion of cement-to-aggregate of 1:5. A commercial admixture was used at a constant content. The amount of water was variable to achieve a consistency of 175±10 mm. The short- and long-term mortar properties were evaluated. The data were analyzed using a one-way ANOVA. In conclusion, a maximum percentage of 50% recycled concrete sand can be used in an indoor environment.La extracción de arena natural de ríos y costas está provocando graves problemas ambientales en muchas partes del mundo, mientras que la fracción fina de los áridos reciclados de residuos de hormigón está infrautilizada como material de construcción. El objetivo de este artículo es determinar el máximo porcentaje de sustitución de arena natural por arena reciclada en la fabricación de morteros M-10. Cinco niveles de sustitución en volumen fueron ensayados: 0%, 25%, 50%, 75% y 100%. Las mezclas fueron hechas con cemento CEM II/BL 32,5 N en una relación volumétrica cemento-árido de 1:5. Se utilizó un aditivo comercial a dosis constante. El agua se ajustó experimentalmente para conseguir una consistencia de 175±10 mm. Se evaluaron las propiedades de los morteros a corto y largo plazo. Los datos se analizaron mediante una ANOVA-simple. En conclusión, un porcentaje máximo del 50% de arena reciclada de hormigón puede usarse en interiores.

  8. Determination of shear parameters of concrete filled head-straight masonry brick walls

    OpenAIRE

    Reza Amiraslanzadeh; Toshikazu Ikemoto; Saiji Fukada; Masakatsu Miyajima; Sadra Karimzadeh

    2015-01-01

    The aim of present study was determination of shear parameters of reinforced and unreinforced masonry brick walls assembled with Head-straight texture order. Experimental tests carried out on triplets in order to define shear parameters of brick mortar interface, and diagonal compression test in order to define shear strength of masonry panels. According to various interpretations on evaluation of shear strength using diagonal compression test, comparison between mentioned values and those...

  9. Experimental and Numerical Analysis of the Compressive and Shear Behavior for a New Type of Self-Insulating Concrete Masonry System

    Directory of Open Access Journals (Sweden)

    Abu-Bakre Abdelmoneim Elamin Mohamad

    2016-08-01

    Full Text Available The developed study aimed at investigating the mechanical behavior of a new type of self-insulating concrete masonry unit (SCMU. A total of 12 full-grouted wall assemblages were prepared and tested for compression and shear strength. In addition, different axial stress ratios were used in shear tests. Furthermore, numerical models were developed to predict the behavior of grouted specimens using simplified micro-modeling technique. The mortar joints were modeled with zero thickness and their behavior was applied using the traction–separation model of the cohesive element. The experimental results revealed that the shear resistance increases as the level of precompression increases. A good agreement between the experimental results and numerical models was observed. It was concluded that the proposed models can be used to deduct the general behavior of grouted specimens.

  10. Uncertainty in Seismic Capacity of Masonry Buildings

    Directory of Open Access Journals (Sweden)

    Nicola Augenti

    2012-07-01

    Full Text Available Seismic assessment of masonry structures is plagued by both inherent randomness and model uncertainty. The former is referred to as aleatory uncertainty, the latter as epistemic uncertainty because it depends on the knowledge level. Pioneering studies on reinforced concrete buildings have revealed a significant influence of modeling parameters on seismic vulnerability. However, confidence in mechanical properties of existing masonry buildings is much lower than in the case of reinforcing steel and concrete. This paper is aimed at assessing whether and how uncertainty propagates from material properties to seismic capacity of an entire masonry structure. A typical two-story unreinforced masonry building is analyzed. Based on previous statistical characterization of mechanical properties of existing masonry types, the following random variables have been considered in this study: unit weight, uniaxial compressive strength, shear strength at zero confining stress, Young’s modulus, shear modulus, and available ductility in shear. Probability density functions were implemented to generate a significant number of realizations and static pushover analysis of the case-study building was performed for each vector of realizations, load combination and lateral load pattern. Analysis results show a large dispersion in displacement capacity and lower dispersion in spectral acceleration capacity. This can directly affect decision-making because both design and retrofit solutions depend on seismic capacity predictions. Therefore, engineering judgment should always be used when assessing structural safety of existing masonry constructions against design earthquakes, based on a series of seismic analyses under uncertain parameters.

  11. 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

  12. Resistance of Concrete Masonry Walls With Membrane Catcher Systems Subjected to Blast Loading

    Science.gov (United States)

    2010-12-01

    is the lateral displacement at the height-wise center of the wall, y is the crack depth through the thickness, and α is the degree of fixity at the...unreinforced masonry wall are assumed to be fully fixed. Eq. (4) accounts for partial end fixities ( ) of the top and bottom interfaces of the

  13. Important Tenders and Contracts to be Placed in the Near Future - Concrete and Masonry Construction Work for the Control Station and Part of the Annex Laboratory Wing and the Corridor which Connects them to the Main SC Building

    CERN Document Server

    European Organization for Nuclear Research

    1955-01-01

    Important Tenders and Contracts to be Placed in the Near Future - Concrete and Masonry Construction Work for the Control Station and Part of the Annex Laboratory Wing and the Corridor which Connects them to the Main SC Building

  14. Use of Fiber-Reinforced Cements in Masonry Construction and Structural Rehabilitation

    Directory of Open Access Journals (Sweden)

    Ece Erdogmus

    2015-02-01

    Full Text Available The use of fiber reinforcement in traditional concrete mixes has been extensively studied and has been slowly finding its regular use in practice. In contrast, opportunities for the use of fibers in masonry applications and structural rehabilitation projects (masonry and concrete structures have not been as deeply investigated, where the base matrix may be a weaker cementitious mixture. This paper will summarize the findings of the author’s research over the past 10 years in these particular applications of fiber reinforced cements (FRC. For masonry, considering both mortar and mortar-unit bond characteristics, a 0.5% volume fraction of micro fibers in type N Portland cement lime mortar appear to be a viable recipe for most masonry joint applications both for clay and concrete units. In general, clay units perform better with high water content fiber reinforced mortar (FRM while concrete masonry units (CMUs perform better with drier mixtures, so 130% and 110% flow rates should be targeted, respectively. For earth block masonry applications, fibers’ benefits are observed in improving local damage and water pressure resistance. The FRC retrofit technique proposed for the rehabilitation of reinforced concrete two-way slabs has exceeded expectations in terms of capacity increase for a relatively low cost in comparison to the common but expensive fiber reinforced polymer applications. For all of these applications of fiber-reinforced cements, further research with larger data pools would lead to further optimization of fiber type, size, and amount.

  15. Development of Electrode Units for Electrokinetic Desalination of Masonry and Pilot Scale Test at Three locations for Removal of Chlorides

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Christensen, Iben Vernegren; Skibsted, Gry

    2010-01-01

    Electrode units for electrokinetic desalination of masonry has been developed and tested in pilot scale at three different locations. The units are formed as casings with a metallic mesh electrode, and carbonate rich clay to buffer the acid produced at the anode. The case has an extra loose bottom...

  16. Fatigue in Breakwater Concrete Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units.......The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units....

  17. Evaluation of the Properties of Lightweight Concrete Using ...

    African Journals Online (AJOL)

    ADOWIE PERE

    utilization of PWS in structural/insulating lightweight concrete, at lower volume of replacement ... layers, subsequently weakens in strength. Structural lightweight concrete has density of 1440 kg/ m3 to. 1840 kg/m3 compared to normal weight concrete with a density ..... for Lightweight Aggregates for Concrete Masonry. Units.

  18. Innovative AE and NDT techniques for on-site measurement of concrete and masonry structures state-of-the-art report of the RILEM technical committee 239-MCM

    CERN Document Server

    2016-01-01

    This volume, in which on-site measurements of concrete and masonry structures by NDT techniques are comprehensively summarized, focuses on the visualization procedure of the results measured. The research and its outcomes presented in this book treat applications of NDT techniques to on-site measurements. These on-site measurements have been marginally successful as each technique requires a particular analysis. In this regard, visualization and imaging of results are in great demand for practitioners and engineers for inspection. The book will therefore be of great value to the field. .

  19. Fatigue in Breakwater Concrete Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1985-01-01

    The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units. Results showing significant fatigue from impact tests with Dolosse...... made of unreinforced and steel fibre reinforced flyash concrete are presented. Moreover universal graphs for fatigue in armour units made of conventional unreinforced concrete exposed to impact load and pulsating load are presented. The effect of fibre reinforcement and the implementation of fatigue...

  20. Energy Efficiency Improvement and Cost Saving Opportunities for the Concrete Industry

    NARCIS (Netherlands)

    Kermeli, Katerina; Worrell, E.; Masanet, Eric

    2011-01-01

    The U.S. concrete industry is the main consumer of U.S.-produced cement. The manufacturing of ready mixed concrete accounts for about 75% of the U.S. concrete production following the manufacturing of precast concrete and masonry units. The most significant expenditure is the cost of materials

  1. Integrated and holistic suitability assessment of recycling options for masonry rubble

    Science.gov (United States)

    Herbst, T.; Rübner, K.; Meng, B.

    2012-04-01

    Our industrial society depends on continuous mining and consumption of raw materials and energy. Besides, the building sector causes one of the largest material streams in Germany. On the one hand, the building sector is connected with a high need in material and energetic resources as well as financial expenditures. On the other hand, nearly 50 % of the volume of waste arises from the building industry. During the last years, the limitation of natural resources, increasing negative environmental consequences as well as rising prices and shortages of dump space have led to a change in thinking in the building and waste industry to a closed substance cycle waste management. In consideration of the production figures of the main kinds of masonry units (clay bricks, sand-lime bricks, autoclaved aerated concrete brick, concrete blocks), a not unimportant quantity of masonry rubble (including gypsum plaster boards, renders, mortars and mineral insulating materials) of more than 20 million tons per year is generated in the medium term. With regard to a sustainable closed substance cycle waste management, these rest masses have to be recycled if possible. Processed aggregates made from masonry rubble can be recycled in the production of new masonry units under certain conditions. Even carefully deconstructed masonry units can once more re-used as masonry units, particularly in the area of the preservation of monuments and historical buildings. In addition, masonry rubble in different processing qualities is applied in earth and road construction, horticulture and scenery construction as well as concrete production. The choice of the most suitable recycling option causes technical, economical and ecological questions. At present, a methodology for a comprehensive suitability assessment with a passable scope of work does not exist. Basic structured and structuring information on the recycling of masonry rubble is absent up to now. This as well as the economic and technical

  2. APPLICATION OF MIKRODUR IN MASONRY SYSTEMS

    Directory of Open Access Journals (Sweden)

    Makarenkova Yuliya Viktorovna

    2012-10-01

    Full Text Available The author describes the problem of production of the ultra lightweight masonry mortar and methods of its solution. Conditions of optimization of the masonry mortar structure are considered in the article. Presently, Microdur is widely used in construction and repair of subsurface structures, tunnels, oil and gas wells. The use of Mikrodur may substantially improve the properties of the masonry mortar (ρр = 941.17 kg/m3, = 11.00 MPa, av = 66.25 kN, compression = 26.50 MPa, ρрstone = 570.47 kg/m3, per unit compression = 46.45 PMa/kg·103, per unit = 19.28 PMa/kg·103, λ = 0.190 Wt/m°С. The thermal conductivity of both bearing and thermal insulation porous concrete blocks is equal to 0.18…0.21 Wt/m°С. Thus, the new envelope structure of homogeneous thermal conductivity has a value of thermotechnical homogeneity ratio = 0.98.

  3. USE OF WOOD RESIDUES OF Pinus spp. FOR SUBSTITUTION TO THE FINE AGGREGATE IN THE PRODUCTION OF CONCRETE BLOCKS FOR STRUCTURAL MASONRY

    Directory of Open Access Journals (Sweden)

    Adauto José Miranda de Lima

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813339This research was developed with the objective of evaluating the potential use of residues of the productionof Pinus spp. sawnwood, as substitution to the fine aggregate of the concrete used for the production ofblocks for structural masonry. The evaluation of the physical characteristics (density, porosity and waterabsorption and mechanics (compression and tension strength of the concrete was evaluated in agreementwith the ABNT normalization. Substitutions of the fine aggregate were tested by percentages of 0, 20,40, 60, 80 and 100% of residue of Pinus spp. in natura, Pinus spp. in natura and with addition of 4,5%CaCl2.2H2O and residue of Pinus spp. pre-treated with extraction in cold water for 48 hours (AF-48H.The compositions were initially used for the production, in laboratory, of cylindrical specimens of 50 mmdiameter, by the use of a molding system for vibrate-compression and later, for producing blocks, withoptimized compositions, in vibrate-press commercial machine. Satisfactory results were obtained withsubstitutions of up to 50% of the mineral fine aggregate for the residue of Pinus spp.

  4. Equipment and Protocols for Quasi-Static and Dynamic Tests of Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC)

    Science.gov (United States)

    2016-08-01

    average tensile strain of up to 5 percent (500 times higher than conventional concrete) and compressive strengths of approximately 40 MPa (5.8 ksi...produce resistance functions for a given type of support conditions. Initial test methods used positive air pressure to apply loads to masonry walls...focused on testing concrete masonry unit (CMU) walls. The CMU walls were built in place. Water is introduced simultaneously on both sides of the panel

  5. EVALUATION OF SHEAR CAPACITY FOR BRICK MASONRY WALLS

    Directory of Open Access Journals (Sweden)

    Partene Eva

    2015-05-01

    Full Text Available The papers presents the results of an experimental program and provides valuable information regarding the behaviour of structural masonry walls built up using ceramic blocks with hollows, which represents a very common system for low-rise residential buildings, up to 4 stories, depending on the seismic acceleration on site. A number of six masonry walls where tested in bear state being subjected to constant vertical loading and to cyclic in-plane horizontal loads. The main objective was to determine the shear capacity for unreinforced masonry walls and reinforced masonry walls. The experimental results were also useful to determine the contribution of the reinforcing of the masonry walls with concrete columns. The comparison between unreinforced masonry and reinforced masonry has a great importance due to the fact that the Romanian Seismic Standards have imposed the reinforcement in seismic areas for building with more than 1 storey. Further studies will be conducted on strengthening the masonry walls using FRP materials.

  6. Masonry structural design for buildings

    Science.gov (United States)

    1982-08-01

    Masonry structures shall be designed in accordance with the requirements of this manual. Applicable building codes and exceptions thereto are noted in the manual. The structural design information is based upon the engineered design concept in which walls and columns are analyzed on a stress basis which is considered a refinement of commonly used empirical methods. The design curves and sample calculations will materially contribute to the speed and accuracy of the design of brick and concrete masonry buildings. Since some of the referenced Army publications may be in conflict with Navy criteria, engineers using this manual for Navy projects should use applicable Navy criteria.

  7. Masonry concrete block strength compound with sawdust according to residue treatment - doi: 10.4025/actascitechnol.v34i3.14372

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima Souza

    2012-05-01

    Full Text Available The behavior of building blocks with the partial replacement of fine aggregates by sawdust is evaluated. The parameter adopted comprised analysis of the compressive strength according to the treatment applied to sawdust residue of the species Dinizia Excelsa Ducke (red angelim. Blocks were composed by replacing fine aggregates by sawdust at 5% weight. Before mixing the wood residues to the concrete, the former underwent treatment so that wood residues could be compatible with the cement matrix. Two treatment processes were investigated. The first treatment comprised the washing of residues in an alkaline solution (lime at a 5% proportion (weight / weight. The second treatment comprised the immersion of the residue in aluminum sulfate. Analysis was undertaken from compressive strength assays of the blocks on the 7th and 28th day. Results showed low efficiency in the alkaline-based treatment (lime and good performance in the aluminum sulfate-based treatment. The production of masonry blocks with a replacement of 5% fine aggregates for this type of treatment and species studied is possible. 

  8. 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.

  9. Utilization of crushed clay brick in concrete industry

    Directory of Open Access Journals (Sweden)

    Ali A. Aliabdo

    2014-03-01

    Full Text Available A comprehensive experimental program regarding the use of recycled aggregates produced from demolition of brick buildings is presented. The brick wastes were crushed, sorted and classified into coarse and fine aggregates as well as powder (CBP. The first phase of the research focuses on the effect of incorporating recycled aggregates on physico-mechanical properties of paste, mortar and concrete. Non-traditional tests including X-ray diffraction (XRD, thermo-gravimetric analysis (TGA and micro-structural analysis (MSA were performed. The second phase of the program explores the effect of using recycled aggregates on properties of concrete masonry units. A total of 44 mixtures were utilized throughout the program. Results show cement paste when modified with 25% CBP achieves smaller pore size and lower weight loss under high temperature than reference paste. Furthermore, the use of recycled aggregates reduces the overall unit weight of concrete masonry units. Actually, modified concrete masonry units incorporating recycled aggregates achieve lower unit weight, higher thermal resistance and absorption rate than reference units. Although considerable strength reduction is noticeable by substitution, compressive strength levels meet the Egyptian specifications limitations. Critical replacement ratios are suggested to produce load bearing-concrete masonry units. Based on experimental evidences, it can be stated that the use of recycled aggregate and dust made of clay bricks is promising in many applications where the thermal resistance, cost and environmental aspects are imperative.

  10. The United States Merchant Marine Academy Historic District: Nomination to the National Register of Historic Places

    Science.gov (United States)

    2014-10-01

    of Historic Places NY SHPO New York State Historic Preservation Office SUNY State University of New York USNR US Navy Reserve USMMA United States...echoed the Beaux Arts classicism of Wiley Hall, thus creating a unified architectural complex. With the exception of Wiley Hall, which is masonry ...and stucco, all buildings are of buff-colored concrete masonry units with cast stone (concrete) accents, and the build- ings display a generally

  11. Comparison of fundamental natural period of masonry and reinforced concrete buildings retrieved from experimental campaigns performed in Italy, Greece and Spain

    Science.gov (United States)

    Nigro, Antonella; Ponzo, Felice C.; Ditommaso, Rocco; Auletta, Gianluca; Iacovino, Chiara; Nigro, Domenico S.; Soupios, Pantelis; García-Fernández, Mariano; Jimenez, Maria-Jose

    2017-04-01

    Aim of this study is the experimental estimation of the dynamic characteristics of existing buildings and the comparison of the related fundamental natural period of the buildings (masonry and reinforced concrete) located in Basilicata (Italy), in Madrid (Spain) and in Crete (Greece). Several experimental campaigns, on different kind of structures all over the world, have been performed in the last years with the aim of proposing simplified relationships to evaluate the fundamental period of buildings. Most of formulas retrieved from experimental analyses provide vibration periods smaller than those suggested by the Italian Seismic Code (NTC2008) and the European Seismic Code (EC8). It is known that the fundamental period of a structure play a key role in the correct estimation of the spectral acceleration for seismic static analyses and to detect possible resonance phenomena with the foundation soil. Usually, simplified approaches dictate the use of safety factors greater than those related to in depth dynamic linear and nonlinear analyses with the aim to cover any unexpected uncertainties. The fundamental period calculated with the simplified formula given by both NTC 2008 and EC8 is higher than the fundamental period measured on the investigated structures in Italy, Spain and Greece. The consequence is that the spectral acceleration adopted in the seismic static analysis may be significantly different than real spectral acceleration. This approach could produces a decreasing in safety factors obtained using linear seismic static analyses. Based on numerical and experimental results, in order to confirm the results proposed in this work, authors suggest to increase the number of numerical and experimental tests considering also the effects of non-structural components and soil during small, medium and strong motion earthquakes. Acknowledgements This study was partially funded by the Italian Department of Civil Protection within the project DPC-RELUIS 2016 - RS4

  12. Field documentation and client presentation of IR inspections on new masonry structures

    Science.gov (United States)

    McMullan, Phillip C.

    1991-03-01

    With the adoption of American Concrete Institute's Design Standard 530 (ACI 530-88/ASCE 5-88) and Specifications (ACI 530.1-88/ASCE 6-88) by more governing bodies throughout the United States, the level and method of inspecting masonry structures is rapidly changing. These new standards set forth inspection criteria such that the Professional of Record (i.e., Architect), can determine the level of inspection based on the type and complexity of the structure being built. For example, a hospital would require considerably more inspection than a Seven-Eleven mini-market. However, the standards require that all new masonry buildings must be inspected. Infrared thermography has proven to be an effective tool to assist in the required inspections. These inspections focus on evaluating masonry for compliance with the design specifications with regard to material, structural strength and thermal performance, the use of video infrared thermography provides a thorough systematic method for inspection of structural solids and thermal integrity of masonry structures. In conducting masonry inspections, the creation of a permanent, well-documented record is valuable in avoiding potential controversy over the inspection findings. Therefore, the inspection method, verification of findings, and presentation of the inspection data are key to the successful use of infrared thermography as an inspection tool. This paper will focus on the method of inspection which TSI employs in conducting new masonry inspections. Additionally, an important component of any work is the presentation of the data. We will look at the information which is generated during this type of inspection and how that data can be converted into a usable report for the various parties involved in construction of a new masonry building.

  13. Development of Alkali Activated Geopolymer Masonry Blocks

    Science.gov (United States)

    Venugopal, K.; Radhakrishna; Sasalatti, Vinod

    2016-09-01

    Cement masonry units are not considered as sustainable since their production involves consumption of fuel, cement and natural resources and therefore it is essential to find alternatives. This paper reports on making of geopolymer solid & hollow blocks and masonry prisms using non conventional materials like fly ash, ground granulated blast furnace slag (GGBFS) and manufactured sand and curing at ambient temperature. They were tested for water absorption, initial rate of water absorption, dry density, dimensionality, compressive, flexural and bond-strength which were tested for bond strength with and without lateral confinement, modulus of elasticity, alternative drying & wetting and masonry efficiency. The properties of geopolymer blocks were found superior to traditional masonry blocks and the masonry efficiency was found to increase with decrease in thickness of cement mortar joints. There was marginal difference in strength between rendered and unrendered geopolymer masonry blocks. The percentage weight gain after 7 cycles was less than 6% and the percentage reduction in strength of geopolymer solid blocks and hollow blocks were 26% and 28% respectively. Since the properties of geopolymer blocks are comparatively better than the traditional masonry they can be strongly recommended for structural masonry.

  14. Properties of dry masonry mixtures based on hollow aluminosilicate microspheres

    Directory of Open Access Journals (Sweden)

    Semenov Vyacheslav

    2017-01-01

    Full Text Available At present, there is a steady increase in the volume of housing construction in the Russian Federation. The modern trends in the field of energy and resource saving determine the need of the use of efficient building materials that ensure the safety, comfort and minimum cost of housing construction. Among the materials, often used for erecting of fencing structures, it is possible to note effective small-piece elements (ceramic and light-weight concrete units, etc.. To ensure the solidity of such structures, it is necessary to use the masonry mortars whose properties correspond to those of the main wall material. The existing dry mixes for obtaining of such mortars are expensive and often do not meet the minimum physical-and-mechanical and exploitation requirements. The solution of this problem is the usage of the hollow ceramics (aluminosilicate microspheres as a filler for such mixes. The article presents the results of studies of the main physical-and-mechanical and exploitation characteristics of dry masonry mixes with hollow ceramics microspheres modified with various chemical additives. The effect of the compounding factors on the average density and strength of dry masonry mixes was studied. The compositions have been optimized by the methods of mathematical planning.

  15. Final Report: Self Consolidating Concrete Construction for Modular Units

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, Russell [Georgia Inst. of Technology, Atlanta, GA (United States); Kahn, Lawrence [Georgia Inst. of Technology, Atlanta, GA (United States); Kurtis, Kimberly [Georgia Inst. of Technology, Atlanta, GA (United States); Petrovic, Bojan [Georgia Inst. of Technology, Atlanta, GA (United States); Loreto, Giovanni [Georgia Inst. of Technology, Atlanta, GA (United States); Van Wyk, Jurie [Westinghouse Electric Company, Cranberry Township, PA (United States); Canterero-Leal, Carlos [Westinghouse Electric Company, Cranberry Township, PA (United States)

    2016-07-29

    This report outlines the development of a self-consolidating concrete (also termed “self-compacting concrete” or SCC) so that concrete placement can be made into steel plate composite (SC) modular structures without the need for continuous concrete placement. As part of the research, SCC mixtures were developed and validated to ensure sufficient shear capacity across cold-joints, while minimizing shrinkage and temperature increase during curing to enhance concrete bonding with the steel plate construction found in modular units. The self-roughening concrete produced as part of this research was assessed in SC structures at three scales: small-scale shear-friction specimens, mid-scale beams tested in in-plane and out-of-plane bending, and a full-scale validation test using an SC module produced by Westinghouse as part of the Plant Vogtle expansion. The experiments show that the self-roughening concrete can produce a cold-joint surface of 0.25 inches (6 mm) without external vibration during concrete placement. The experiments and subsequent analysis show that the shear friction provisions of ACI 318-14, Section 22.9 can be used to assess the shear capacity of the cold-joints in SC modular construction, and that friction coefficient of 1.35 is appropriate for use with these provisions.

  16. Experimental Measurements of Prestressed Masonry with using Sliding Joint

    Directory of Open Access Journals (Sweden)

    Stara Marie

    2014-06-01

    Full Text Available Contribution deals with experimental measurements of deformations in the place exposed to local load caused by additional pre-stressing. The measurements are made at the masonry corner built in the laboratory equipment. The laboratory equipment was designed at Faculty of Civil Engineering VŠB-Technical University of Ostrava for measurement tri-axial stress-strain conditions in masonry. In this masonry corner two pre-stressing bars are placed. These bars are in different height and are anchored to the anchor plates, which transfer pre-stressing forces to the masonry. The specimen for laboratory testing is performed in the proportion to the reality of 1:1. In the bottom part masonry is inserted asphalt strip. It operates in the masonry like a sliding joint and reduces the shear stress at interface between concrete and masonry structures. The results are compared with the results of masonry without the use of sliding joints, including comment on the effect of sliding joints on the pre-stressing masonry structures.

  17. BERM BREAKWATERS WITH CONCRETE BLOCKS AS ARMOUR UNITS

    OpenAIRE

    Camara Aguilera, Altea

    2013-01-01

    The objective of this thesis is to test the hydraulic stability of berm breakwaters with concrete armour units. To achieve this, five breakwater models were tested with the same wave program. All the models were modifications of the Sirevåg berm breakwater. The modifications consisted in the replacement of the class I stone form the armour layer by two different concrete units, cubes and cubipodsThe design waves were Hs,100=7.0 m, Tz=10.6 s. HoTo=48. The wave program consisted in 7 different ...

  18. Experimental study on compressive strength of sediment brick masonry

    Science.gov (United States)

    Woen, Ean Lee; Malek, Marlinda Abdul; Mohammed, Bashar S.; Chao-Wei, Tang; Tamunif, Muhammad Thaqif

    2018-02-01

    The effects of pre-wetted unit bricks, mortar type and slenderness ratio of prisms on the compressive strength and failure mode of newly developed sediment brick have been evaluated and compared to clay brick and cement-sand bricks. The results show that pre-wetted sediment brick masonry exhibits higher compressive strength of up to 20% compared to the dry sediment masonry. Using cement-lime mortar leads to lower compressive strength compared to cement mortar. However, the sediment brick masonry with the cement lime mortar exhibit higher compressive strength in comparison with cement mortar masonry. More of diagonal shear cracks have been observed in the failure mode of the sediment bricks masonry compared to clay and cement-sand bricks masonry that show mostly vertical cracks and crushing. The sediment unit bricks display compressive strength in between clay and cement-sand bricks.

  19. Laterally loaded masonry

    DEFF Research Database (Denmark)

    Raun Gottfredsen, F.

    In this thesis results from experiments on mortar joints and masonry as well as methods of calculation of strength and deformation of laterally loaded masonry are presented. The strength and deformation capacity of mortar joints have been determined from experiments involving a constant compressive...... stress and increasing shear. The results show a transition to pure friction as the cohesion is gradually destroyed. An interface model of a mortar joint that can take into account this aspect has been developed. Laterally loaded masonry panels have also been tested and it is found to be characteristic...... that laterally loaded masonry exhibits a non-linear load-displacement behaviour with some ductility....

  20. Numerical Investigations On The Seismic Behaviour Of Confined Masonry Walls

    International Nuclear Information System (INIS)

    Calderini, Chiara; Cattari, Serena; Lagomarsino, Sergio

    2008-01-01

    In the last century, severe earthquakes highlighted the seismic vulnerability of unreinforced masonry buildings. Many technological innovations have been introduced in time in order to improve resistance, ductility, and dissipation properties of this type of constructions. The most widely diffused are reinforced masonry and confined masonry. Damage observation of recent earthquakes demonstrated the effectiveness of the response of confined masonry structures to seismic actions. In general, in this type of structures, reinforced concrete beams and columns are not main structural elements, however, they have the following functions: to confine masonry in order to increase its ductility; to bear tensile stresses derived from bending; to contrast the out-of-plane overturning of masonry panels. It is well evident that these functions are as much effectively performed as the connection between masonry and reinforced concrete elements is good (for example by mean of local interlocking or reinforcements). Confined masonry structures have been extensively studied in the last decades both from a theoretical point of view and by experimental tests Aims of this paper is to give a contribution to the understanding of the seismic behaviour of confined masonry walls by means of numerical parametrical analyses. There latter are performed by mean of the finite element method; a nonlinear anisotropic constitutive law recently developed for masonry is adopted. Comparison with available experimental results are carried out in order to validate the results. A comparison between the resistance obtained from the numerical analyses and the prevision provided by simplified resistance criteria proposed in literature and in codes is finally provided

  1. Final Report: Self-Consolidating Concrete Construction for Modular Units

    International Nuclear Information System (INIS)

    Gentry, Russell; Kahn, Lawrence; Kurtis, Kimberly; Petrovic, Bojan; Loreto, Giovanni; Van Wyk, Jurie; Canterero-Leal, Carlos

    2016-01-01

    This report focuses on work completed on DE-NE0000667, Self-Consolidating Concrete for Modular Units, in connection with the Department of Energy Nuclear Energy Enabling Technologies (DOE-NEET) program. This project was completed in the School of Civil and Environmental Engineering at the Georgia Institute of Technology, with Westinghouse Corporation as the industrial partner. The primary objective of this project was to develop self-consolidating concrete (also termed ''self-compacting concrete'' or SCC) mixtures so that concrete placement can be made into steel plate composite (SC) modular structures without the need for continuous concrete placement. As part of the research, SCC mixtures were developed and validated to ensure sufficient shear capacity across cold-joints, while minimizing shrinkage and temperature increase during curing to enhance concrete bonding with the steel plate construction found in modular units. The SCC mixtures developed were able to carry shearing forces across the cold-joint boundaries. This ''self-roughening'' was achieved by adding a tailored fraction of lightweight aggregate (LWA) to the concrete mix, some of which raised to the surface during curing, forming a rough surface on which subsequent concrete placements were made. The self-roughening behavior was validated through three sets of structural tests. Shear friction on small-scale specimens with cold joints was assessed using varying fractions of LWA and with varying amounts of external steel plate reinforcement. The results show that the shear friction coefficient, to be used with the provisions of ACI 318-14, Section 22.9, can be taken as 1.35. Mid-scale beam tests were completed to assess the cold-joint capacity in both in-plane and out-of-plane bending. The results showed that the self-roughened joints performed as well as monolithic joints. The final assessment was a full-scale test using a steel composite module supplied by

  2. Initiation of Failure for Masonry Subject to In-Plane Loads through Micromechanics

    Directory of Open Access Journals (Sweden)

    V. P. Berardi

    2016-01-01

    Full Text Available A micromechanical procedure is used in order to evaluate the initiation of damage and failure of masonry with in-plane loads. Masonry material is viewed as a composite with periodic microstructure and, therefore, a unit cell with suitable boundary conditions is assumed as a representative volume element of the masonry. The finite element method is used to determine the average stress on the unit cell corresponding to a given average strain prescribed on the unit cell. Finally, critical curves representing the initiation of damage and failure in both clay brick masonry and adobe masonry are provided.

  3. Basic Deformation Parameters of Solid Clay Bricks and Small Masonry Walls

    OpenAIRE

    P. Bouška; D. Pume

    2000-01-01

    The basic mechanical properties of clay brick masonry and its components were experimentally investigated in the laboratories of the Klokner Institute. The test specimens of masonry materials and the relevant mechanical properties have been identified in solid clay bricks and cement-lime mortar. The aim of the research activity was to study both the deformability of the prevailing type of clay masonry in the existing buildings, i.e. the masonry made from the solid clay units and the lim...

  4. Final Report: Self-Consolidating Concrete Construction for Modular Units

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, Russell [Georgia Inst. of Technology, Atlanta, GA (United States); Kahn, Lawrence [Georgia Inst. of Technology, Atlanta, GA (United States); Kurtis, Kimberly [Georgia Inst. of Technology, Atlanta, GA (United States); Petrovic, Bojan [Georgia Inst. of Technology, Atlanta, GA (United States); Loreto, Giovanni [Georgia Inst. of Technology, Atlanta, GA (United States); Van Wyk, Jurie [Westinghouse Inc., Cranberry Township, PA (United States); Canterero-Leal, Carlos [Westinghouse Inc., Cranberry Township, PA (United States)

    2016-07-29

    This report focuses on work completed on DE-NE0000667, Self-Consolidating Concrete for Modular Units, in connection with the Department of Energy Nuclear Energy Enabling Technologies (DOE-NEET) program. This project was completed in the School of Civil and Environmental Engineering at the Georgia Institute of Technology, with Westinghouse Corporation as the industrial partner. The primary objective of this project was to develop self-consolidating concrete (also termed “self-compacting concrete” or SCC) mixtures so that concrete placement can be made into steel plate composite (SC) modular structures without the need for continuous concrete placement. As part of the research, SCC mixtures were developed and validated to ensure sufficient shear capacity across cold-joints, while minimizing shrinkage and temperature increase during curing to enhance concrete bonding with the steel plate construction found in modular units. The SCC mixtures developed were able to carry shearing forces across the cold-joint boundaries. This “self-roughening” was achieved by adding a tailored fraction of lightweight aggregate (LWA) to the concrete mix, some of which raised to the surface during curing, forming a rough surface on which subsequent concrete placements were made. The self-roughening behavior was validated through three sets of structural tests. Shear friction on small-scale specimens with cold joints was assessed using varying fractions of LWA and with varying amounts of external steel plate reinforcement. The results show that the shear friction coefficient, to be used with the provisions of ACI 318-14, Section 22.9, can be taken as 1.35. Mid-scale beam tests were completed to assess the cold-joint capacity in both in-plane and out-of-plane bending. The results showed that the self-roughened joints performed as well as monolithic joints. The final assessment was a full-scale test using a steel composite module supplied by Westinghouse and similar in construction to

  5. Precast concrete unit assessment through GPR survey and FDTD modelling

    Science.gov (United States)

    Campo, Davide

    2017-04-01

    Precast concrete elements are widely used within United Kingdom house building offering ease in assembly and added values as structural integrity, sound and thermal insulation; most common concrete components include walls, beams, floors, panels, lintels, stairs, etc. The lack of respect of the manufacturer instruction during assembling, however, may induce cracking and short/long term loss of bearing capacity. GPR is a well-established not destructive technique employed in the assessment of structural elements because of real-time imaging, quickness of data collecting and ability to discriminate finest structural details. In this work, GPR has been used to investigate two different precast elements: precast reinforced concrete planks constituting the roof slab of a school and precast wood-cement blocks with insulation material pre-fitted used to build a perimeter wall of a private building. Visible cracks affected both constructions. For the assessment surveys, a GSSI 2.0 GHz GPR antenna has been used because of the high resolution required and the small size of the antenna case (155 by 90 by 105mm) enabling scanning up to 45mm from any obstruction. Finite Difference Time Domain (FDTD) numerical modelling was also performed to build a scenario of the expected GPR signal response for a preliminary real-time interpretation and to help solve uncertainties due to complex reflection patterns: simulated radargrams were built using Reflex Software v. 8.2, reproducing the same GPR pulse used for the surveys in terms of wavelet, nominal frequency, sample frequency and time window. Model geometries were derived from the design projects available both for the planks and the blocks; the electromagnetic properties of the materials (concrete, reinforcing bars, air-filled void, insulation and wooden concrete) were inferred from both values reported in literature and a preliminary interpretation of radargrams where internal layer interfaces were clearly recognizable and

  6. Restrained shrinkage of masonry walls

    NARCIS (Netherlands)

    Zijl, G.P.A.G. van; Rots, J.G.

    1998-01-01

    State of the art computational rnechanics, in combination with experimental programmes have a lot to offer in providing insight, characterization of total behaviour and predictive ability of structural masonry. Here numerical research towards rationalizing masonry wall movement joint positioning and

  7. Basic Deformation Parameters of Solid Clay Bricks and Small Masonry Walls

    Directory of Open Access Journals (Sweden)

    P. Bouška

    2000-01-01

    Full Text Available The basic mechanical properties of clay brick masonry and its components were experimentally investigated in the laboratories of the Klokner Institute. The test specimens of masonry materials and the relevant mechanical properties have been identified in solid clay bricks and cement-lime mortar. The aim of the research activity was to study both the deformability of the prevailing type of clay masonry in the existing buildings, i.e. the masonry made from the solid clay units and the lime-cement mortar, and the most important mechanical properties of masonry components.

  8. Seismic performance of masonry-infilled RC frames

    Directory of Open Access Journals (Sweden)

    Mircea Bârnaure

    2016-09-01

    Full Text Available The masonry infill of RC frames structures is generally considered as non-structural. The design of the concrete frames is often made by ignoring the influence of the masonry infill, which is only accounted for its mass. The experience on buildings submitted to earthquakes shows that masonry infill walls completely change the behaviour of bare frames due to increased initial stiffness and low deformability. The way in which masonry infills affect the RC frames members is difficult to predict, as different failure modes can occur either in the masonry or in the surrounding frame. In addition to local effects, the position of the masonry infills at different levels can lead to structural irregularity, with a strong influence on the global seismic response of the building. Less infilled stories, also called soft stories, have a particularly unfavourable behaviour under seismic loads, as frame members at these levels are more susceptible to failure. This paper analyses the differences in the behaviour of bare and infilled frames through numerical modelling. Nonlinear push-over analyses of infilled frames are carried out under in-plane vertical and lateral loading. The infill panels are modelled as equivalent single diagonal struts. Several force-displacements laws are considered for these diagonals.

  9. Specifications for Supplementary Classroom Units, Stressed Skin Panel.

    Science.gov (United States)

    Waring, Robert B.; And Others

    Complete outline specifications are given for the construction of supplementary classroom units using stressed skin panels. Sections included are--(1) concrete and related work, (2) masonry, (3) structural and miscellaneous metal, (4) curtain walls and metal windows, (5) carpentry and related work, (6) roofing, sheet metal, and related work, (7)…

  10. Specifications for Supplementary Classroom Units "Standard Construction" and "Preframed Construction".

    Science.gov (United States)

    Waring, Robert B.; And Others

    The standards that should be applied to the construction of supplementary classroom units are discussed in this report. Areas dealt with are--(1) general mechanical and electrical work, (2) concrete, (3) masonry, (4) miscellaneous steel and iron, (5) metal windows, (6) carpentry at site, (7) millwork, (8) acoustic treatment, (9) thermal…

  11. Análisis comparativo en base a la sostenibilidad ambiental entre bóvedas de albañileria y estructuras de hormigón Comparative analysis on environmental sustainability between masonry vaults and concrete structures

    Directory of Open Access Journals (Sweden)

    Justo García Sanz Calcedo

    2012-01-01

    Full Text Available En este trabajo se compara desde una perspectiva de sostenibilidad, el impacto medioambiental de una estructura de fábrica horizontal de albañilería mediante bóveda de arista, respecto a un forjado estructural de hormigón armado de tipo reticular, utilizando técnicas basadas en el Análisis del Ciclo de Vida para cuantificar la energía consumida en el proceso de fabricación de los materiales y construcción de la estructura. Se ha detectado que la bóveda consume un 75% menos de energía en el proceso de construcción, emite un 69% menos de OO2 a la atmósfera, tienen un coste medio de fabricación para pequeñas luces similar al de un forjado convencional e inferior cuando se trata de salvar grandes luces, genera un 171% menos de residuos procedentes de embalaje en obra, aunque es necesario mas cantidad de mano de obra y que ésta sea más especializada. Se demuestra que la construcción abovedada satisface con creces las exigencias actuales en cuanto a sostenibilidad, así como que esta técnica constructiva puede convivir con la tecnología propia de la sociedad actual, dando como resultado un producto de altas prestaciones económicas, funcionales y energéticas.This paper compares, from a sustainability perspective, the environmental impact of a masonry arris vault with respect to a reticulated reinforced concrete slab, using techniques based on the Life Cycle Assessment to quantify the energy used in the manufacturing process of materials and in the construction of the structure. It has been detected that the vault consumes 75% less energy in the construction process, it emits 69% less CO2 into the atmosphere, it has an average manufacturing cost for short spans similar to a conventional slab, but much lower when large spans have to be covered, and it generates 171% less packaging waste from works, but it needs a larger and more skilled labor force. This paper shows that the vaulted building fully meets the current sustainability

  12. Components interaction in timber framed masonry structures subjected to lateral forces

    Directory of Open Access Journals (Sweden)

    Andreea DUTU

    2012-07-01

    Full Text Available Structures with timber framed masonry represent a special typology that is frequently found in Europe and other countries of the world. They are traditional buildings, non-engineered, which showed an unexpected redundancy during earthquakes where reinforced concrete buildings (improperly constructed collapsed. In the paper, aspects regarding the interaction between timber elements and masonry are mainly addressed, that were observed both in experimental studies, but also in the in situ seismic behavior of this type of structure during important earthquakes.

  13. Masonry infill performance during the Northridge earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, R.D. [Lockheed Martin Energy Systems, Oak Ridge, TN (United States); Bennett, R.M.; Fischer, W.L. [Univ. of Tennesee, Knoxville, TN (United States); Adham, S.A. [Agbabian Associates, Pasadena, CA (United States)

    1996-03-08

    The response of masonry infills during the 1994 Northridge, California earthquake is described in terms of three categories: (1) lowrise and midrise structures experiencing large near field seismic excitations, (2) lowrise and midrise structures experiencing moderate far field excitation, and (3) highrise structures experiencing moderate far field excitation. In general, the infills provided a positive beneficial effect on the performance of the buildings, even those experiencing large peak accelerations near the epicenter. Varying types of masonry infills, structural frames, design conditions, and construction deficiencies were observed and their performance during the earthquake indicated. A summary of observations of the performance of infills in other recent earthquakes is given. Comparison with the Northridge earthquake is made and expected response of infill structures in lower seismic regions of the central and eastern United States is discussed.

  14. 75 FR 81663 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Concrete...

    Science.gov (United States)

    2010-12-28

    ... for OMB Review; Comment Request; Concrete and Masonry Construction Standard ACTION: Notice. SUMMARY... Administration (OSHA) sponsored information collection request (ICR) titled, ``Concrete and Masonry Construction...: Construction firms engaged in the erection of concrete formwork are required to post warning signs/barriers in...

  15. Analysis Of Masonry Infilled RC Frame Structures Under Lateral Loading

    Directory of Open Access Journals (Sweden)

    Barnaure Mircea

    2015-03-01

    Full Text Available Partition walls are often made of masonry in Romania. Although they are usually considered non-structural elements in the case of reinforced concrete framed structures, the infill panels contribute significantly to the seismic behaviour of the building. Their impact is difficult to assess, mainly because the interaction between the bounding frame and the infill is an intricate issue. This paper analyses the structural behaviour of a masonry infilled reinforced concrete frame system subjected to in - plane loading. Three numerical models are proposed and their results are compared in terms of stiffness and strength of the structure. The role of the openings in the infill panel on the behaviour is analysed and discussed. The effect of gaps between the frame and the infill on the structural behaviour is also investigated. Comparisons are made with the in-force Romanian and European regulations provisions.

  16. Estimation of Peak Wave Stresses in Slender Complex Concrete Armor Units

    DEFF Research Database (Denmark)

    Howell, G.L.; Burcharth, H. F.; Rhee, Joon R

    1991-01-01

    Recent methods for the structural design of concrete armor units divide the forces into static loads, impact loads, and wave or pulsating loads. Physical model technology is being developed at several laboratories to measure wave loads on model armor units. While this technology represents...... significant progress, structural designers require a maximum stress value to design armor units....

  17. Stress State Analysis and Failure Mechanisms of Masonry Columns Reinforced with FRP under Concentric Compressive Load

    Directory of Open Access Journals (Sweden)

    Jiří Witzany

    2016-04-01

    Full Text Available The strengthening and stabilization of damaged compressed masonry columns with composites based on fabrics of high-strength fibers and epoxy resin, or polymer-modified cement mixtures, belongs to novel, partially non-invasive and reversible progressive methods. The stabilizing and reinforcing effect of these fabrics significantly applies to masonry structures under concentric compressive loading whose failure mechanism is characterized by the appearance and development of vertical tensile cracks accompanied by an increase in horizontal masonry strain. During the appearance of micro and hairline cracks (10−3 to 10−1 mm, the effect of non-pre-stressed wrapping composite is very small. The favorable effect of passive wrapping is only intensively manifested after the appearance of cracks (10−1 mm and bigger at higher loading levels. In the case of “optimum” reinforcement of a masonry column, the experimental research showed an increase in vertical displacements δy (up to 247%, horizontal displacements δx (up to 742% and ultimate load-bearing capacity (up to 136% compared to the values reached in unreinforced masonry columns. In the case of masonry structures in which no intensive “bed joint filler–masonry unit” interaction occurs, e.g., in regular coursed masonry with little differences in the mechanical characteristics of masonry units and the binder, the reinforcing effect of the fabric applies only partially.

  18. Experimental investigation of the seismic performance of the R/C frames with reinforced masonry infills

    Science.gov (United States)

    Tanjung, Jafril; Maidiawati, Nugroho, Fajar

    2017-10-01

    Intensive studies regarding the investigation of seismic performance of reinforced concrete (R/C) frames which are infilled with brick masonry walls have been carried out by several researchers within the last three-decades. According to authors' field and experimentally experiences conclude that the unreinforced brick masonry infills significantly contributes to increase the seismic performance of the R/C frame structure. Unfortunately, the presence of brick masonry infill walls causes several undesirable effects such as short column, soft-storey, torsion and out of plane collapse. In this study, a strengthening technique for the brick masonry infills were experimentally investigated to improve the seismic performance of the R/C frame structures. For this purpose, four experimental specimens have been prepared, i.e. one of bare R/C frame (BF), one of R/C frame infilled with unreinforced brick-masonry wall (IFUM) and two of R/C frames were infilled with reinforced brick-masonry wall (IFRM-1 and IFRM-2). The bare frame and R/C frame infilled with unreinforced brick-masonry wall represents the typical R/C buildings' construction in Indonesia assuming the brick-masonry wall as the non-structural elements. The brick-masonry wall infills in specimens IFRM-1 and IFRM-2 were strengthened by using embedded ϕ4 plain steel bar on their diagonal and center of brick-masonry wall, respectively. All specimens were laterally pushed-over. The lateral loading and its lateral displacement, failure mechanism and their crack pattern were recorded during experimental works. Comparison of the experimental results of these four specimens conclude that the strengthening of the brick-masonry infills wall gave the significantly increasing of the seismic performance of the R/C frame. The seismic performance was evaluated based on the lateral strength of the R/C specimen. The embedded plain steel bar on brick-masonry also reduces the diagonal crack on the brick-masonry wall. It seems that

  19. A study of concrete for the tumulus disposal units in low-level radioactive waste management

    International Nuclear Information System (INIS)

    Lee, J.H.; Roy, D.M.; Licastro, P.H.; Scheetz, B.E.

    1991-01-01

    The tumulus disposal concept can provide a major means for the disposal of low-level radioactive waste (LLRW) provided the concrete structures of the tumulus disposal units are designed and fabricated for long term durability. As an initial phase of the study, a detailed characterization and testing of the component materials for the tumulus concrete have been evaluated. Key properties of hardened concrete that are important in assuring and predicting the long term durability, which have been evaluated, or are being evaluated, include: water permeability; chloride permeability; sulfate resistance; porosity and pore structure; freeze-thaw resistance; leaching and dissolution; alkali-aggregate reaction; and strength. Those properties were evaluated on samples from field concrete cylinders provided by Martin Marietta Energy Systems (MMES), or samples prepared in the laboratory, or both. The proposed concrete mix design showed an excellent resistance to repeated freeze-thaw cycles, and a very low permeability to chloride. An accelerated test method was used to evaluate alkali-aggregate reactivity in concrete for samples containing representative coarse and fine aggregates proposed for the tumulus concrete, and also conducted for samples cored from the field concrete cylinders

  20. Statics of historic masonry constructions

    CERN Document Server

    Como, Mario

    2016-01-01

    This successful book, which is now appearing in its second edition, presents a comprehensive new Statics of Masonry Constructions. Masonry constructions are the great majority of the buildings in Europe’s historic centres and the most important monuments in its architectural heritage. Given the age of these constructions, the demand for safety assessments and restoration projects is pressing and constant. The book you hold in hands contributes to fill this demand. The second edition integrates the original text of the first edition with new developments, widening and revisions, due to recent research studies achievements. The result is a book that gives a complete picture of the behaviour of the Masonry Constructions. First of all, it gives the fundamentals of its Statics, based on the no-tension assumption, and then it develops the Limit Analysis for the Masonry Constructions. In this framework, through an interdisciplinary approach combining Engineering and Architecture, the book also investigates the sta...

  1. Statics of Historic Masonry Constructions

    CERN Document Server

    Como, Mario

    2013-01-01

    Masonry constructions are the great majority of the buildings in Europe’s historic centres and the most important monuments in its architectural heritage. Given the age of much of these constructions, the demand for safety assessments and restoration projects is pressing and constant. This book aims to help fill this demand presenting a comprehensive new statics of masonry constructions. The book, result of thirty years of research and professional experience, gives the fundamentals of statics of the masonry solid, then applied to the study of statics of arches, piers and vaults. Further, combining engineering and architecture and through an interdisciplinary approach, the book investigates the statical behaviour of many historic monuments, as the Pantheon, the Colosseum,  the domes of S. Maria del Fiore in Florence and of St. Peter in Rome, the Tower of Pisa, the Gothic Cathedrals and the Masonry Buildings under seismic actions.

  2. Evaluation of masonry coatings.

    Science.gov (United States)

    1969-08-01

    This report describes the evaluation of five coating systems to replace the conventional Class 2 rubbed finish now required on concrete structures. The evaluation consisted of preparing test specimens with each of the five coatings and conducting abs...

  3. Evaluation of masonry wall design at nuclear power plants

    International Nuclear Information System (INIS)

    Con, V.N.; Subramonian, N.; Chokshi, N.

    1983-01-01

    The structural integrity of safety-related masonry walls in operating nuclear power plants may not be maintained when subjected to certain loads and load combinations. The paper presents some findings based upon the review of the design and analysis procedures used by the licensees in the reevaluation of safety-related masonry walls. The design criteria developed by the Structural Engineering Branch (SEB) of the United States Nuclear Regulatory Commission (NRC) along with other standard codes such as the Uniform Building Code, ACI 531-79, ATC 3-06, and NCMA were used as guidance in evaluating the design criteria developed by the licensees. The paper deals with the following subject areas: loads and load combinations, allowable stresses, analytical procedures, and modification methods. The paper concludes that, in general, the masonry walls in nuclear power plants comply with the working stress design requirements. In some cases, certain nonlinear analysis methods were used. The applicability of these methods is discussed. (orig.)

  4. Behaviour of masonry structures during the Bhuj earthquake of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    2001-01-26

    Jan 26, 2001 ... units in lime mortar. All such buildings have responded badly whereas, neighbouring brick-in- cement-mortar buildings survived although they developed extensive cracks. The failure pat- tern may be essentially characterized as out-of- plane failure due to the extremely low value. Keywords. Masonry ...

  5. Statics of historic masonry constructions

    CERN Document Server

    Como, Mario

    2017-01-01

    Masonry constructions are the great majority of the buildings in Europe’s historic centres and the most important monuments of its architectural heritage. Given the age of these constructions, the demand for safety assessments and restoration projects is pressing and constant; still within the broad studies in the subject it is not yet recognised, in particular within the seismic area, a unitary approach to deal with Masonry structures. This successful book contributes to clarify the issues with a rigorous approach offering a comprehensive new Statics of Masonry Constructions. This third edition has been driven by some recent developments of the research in the field, and it gives the fundamentals of Statics with an original and rigorous mathematical formulation, further in-depth inquired in this new version. With many refinements and improvements, the book investigates the static behaviour of many historic monuments, such as the Gothic Cathedrals, the Mycenaean Tholoi, the Pantheon, the Colosseum, the dome...

  6. 29 CFR 1926.703 - Requirements for cast-in-place concrete.

    Science.gov (United States)

    2010-07-01

    ..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry... and the erected shoring shall be inspected by an engineer qualified in structural design. (ii) The... Operations—Concrete and Masonry Work, ANSI A10.9-1983, shall be deemed to be in compliance with the provision...

  7. Numerical modelling of failure of cement concrete using a unit cell ...

    Indian Academy of Sciences (India)

    rial. Current study involves; (a) failure analysis of the concrete unit cell when it is subjected to tensile loads, and (b) parametric study of variation of peak strength with shape and volume fraction of aggregate. In this study, circular and square aggregates at various orientations are modelled. The simulation results predict that ...

  8. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Howell, G.L.; Liu, Z.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...

  9. THE EVOLUTION OF THE DESIGN AND CONSTRUCTION OF MASONRY BUILDINGS IN CANADA

    Directory of Open Access Journals (Sweden)

    Robert G. Drysdale

    2012-12-01

    Full Text Available This paper provides an opportunity to formulate a statement of the current status of masonry engineering in Canada with some perspective from the past and some insight into potential for the future. Notwithstanding the fact that this represents the view of the author only, an attempt is made to provide a balanced and comprehensive overview. When we talk about masonry in Canada, by far the largest part of clay brick production and most of the concrete block used are employed in buildings based on the very simple to apply provisions of Part 9 of the National Building Code that applies to small buildings and is not “engineered” through any proper analysis and does not require the participation of a licensed structural engineer. However, growth potential is greatest in the area of engineered masonry. This paper provides information on education, research, development of codes and standards, and the general state of masonry engineering in Canada. Problems facing masonry in terms of maintaining or expanding market share of construction, areas requiring most attention, and opportunities for enhancement of masonry are discussed.

  10. Shaking Table Tests Validating Two Strengthening Interventions on Masonry Buildings

    International Nuclear Information System (INIS)

    De Canio, Gerardo; Poggi, Massimo; Clemente, Paolo; Muscolino, Giuseppe; Palmeri, Alessandro

    2008-01-01

    Masonry buildings constitute quite often a precious cultural heritage for our cities. In order to future generations can enjoy this heritage, thence, effective projects of protection should be developed against all the anthropical and natural actions which may irreparably damage old masonry buildings. However, the strengthening interventions on these constructions have to respect their authenticity, without altering the original conception, not only functionally and aesthetically of course, but also statically. These issues are of central interests in the Messina area, where the seismic protection of new and existing constructions is a primary demand. It is well known, in fact, that the city of Messina lies in a highly seismic zone, and has been subjected to two destructive earthquakes in slightly more than one century, the 1783 Calabria earthquake and the more famous 1908 Messina-Reggio Calabria earthquake. It follows that the retrofitting projects on buildings which survived these two events should be designed with the aim to save the life of occupants operating with 'light' techniques, i.e. respecting the original structural scheme. On the other hand, recent earthquakes, and in particular the 1997 Umbria-Marche sequence, unequivocally demonstrated that some of the most popular retrofitting interventions adopted in the second half the last century are absolutely ineffective, or even unsafe. Over these years, in fact, a number of 'heavy' techniques proliferated, and therefore old masonry buildings suffered, among others, the substitution of existing timber slabs with more ponderous concrete slabs and/or the insertion of RC and steel members coupled with the original masonry elements (walls, arches, vaults). As a result, these buildings have been transformed by unwise engineers into hybrid structures, having a mixed behaviour (which frequently proved to be also unpredictable) between those of historic masonry and new members. Starting from these considerations, a

  11. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  12. Experimental Data and Guidelines for Stone Masonry Structures: a Comparative Review

    International Nuclear Information System (INIS)

    Romano, Alessandra

    2008-01-01

    Indications about the mechanical properties of masonry structures contained in many Italian guidelines are based on different aspects both concerning the constituents material (units and mortar) and their assemblage. Indeed, the documents define different classes (depending on the type, the arrangement and the unit properties) and suggest the use of amplification coefficients for taking into account the influence of different factors on the mechanical properties of masonry. In this paper, a critical discussion about the indications proposed by some Italian guidelines for stone masonry structures is presented. Particular attention is addressed to the classification criteria of the masonry type and to the choice of the amplification factors. Finally, a detailed analytical comparison among the suggested values and some inherent experimental data recently published is performed

  13. The Behaviour of Palm Oil Fibre Block Masonry Prism under Eccentric Compressive Loading

    Science.gov (United States)

    Mokhtar, Mardiha; Kolop, Roslan; Baizura Hamid, Nor; Kaamin, Masiri; Farhan Rosdi, Mohd; Ngadiman, Norhayati; Sahat, Suhaila

    2017-08-01

    Dry-stacked masonry offers great benefits in constructing masonry buildings. Several examples from previous research show that dry masonry is reasonable alternative to the traditional building system. By addition of fibre, the ductility and the propagation of cracking will be improved. This study investigates the dry stack oil palm fibre block prisms which were subjected to eccentricity compression loads. These concrete blocks were cast using a single mould with suitable fibre-cement composition namely 1:4 (cement: sand) and 0.40 water to the cement ratio based on cement weight. Prisms test using 400 (length) × 150 (width) × 510 (height) mm specimen was carried under eccentric load. There were forty eight (48) prisms built with different configurations based on their volume of fibre. In this study, one types of grout were used namely the fine grout of mix 1:3:2 (cement: sand: aggregate (5mm maximum). Based on the test performed, the failure mechanism and influencing parameters were discussed. From compressive strength test result, it shows that the strength of concrete block decreased with the increase of fibre used. Although the control sample has the higher strength compared to concrete with EFB, it can be seen from mode failure of masonry prism that fibre could extend the cracking time. These results show that the oil palm fibre blocks can improve the failure behaviour and suitable to be used as load bearing wall construction in Malaysia.

  14. Fibre Concrete 2017

    Science.gov (United States)

    2017-09-01

    9th international conference on fibre reinforced concretes (FRC), textile reinforced concretes (TRC) and ultra-high performance concretes (UHPC) Preface The Fibre Concrete Conference series is held biennially to provide a platform to share knowledge on fibre reinforced concretes, textile concretes and ultra-high performance concretes regarding material properties and behaviour, technology procedures, topics of long-term behaviour, creep, durability; sustainable aspects of concrete including utilisation of waste materials in concrete production and recycling of concrete. The tradition of Fibre Concrete Conferences started in eighties of the last century. Nowadays the conference is organized by the Department of Concrete and Masonry Structures of the Czech Technical University in Prague, Faculty of Civil Engineering. The 9th International Conference Fibre Concrete 2017 had 109 participants from 27 countries all over the world. 55 papers were presented including keynote lectures of Professor Bažant, Professor Bartoš and Dr. Broukalová. The conference program covered wide range of topics from scientific research to practical applications. The presented contributions related to performance and behaviour of cement based composites, their long-term behaviour and durability, sustainable aspects, advanced analyses of structures from these composites and successful applications. This conference was organized also to honour Professor Zděnek P. Bažant on the occasion of his jubilee and to appreciate his merits and discoveries in the field of fibre reinforced composites, structural mechanics and engineering.

  15. Autoclaved aerated concrete : shaping the evolution of residential construction in the United States.

    OpenAIRE

    Bukoski, Steven C.

    1998-01-01

    CIVINS (Civilian Institutions) Thesis document Precast Autoclaved Aerated Concrete (AAC) is a proven construction material used in Europe for over 70 years. Introduced to the United States in 1990, construction thus far is limited to commercial and custom borne applications. Premium benefits include energy efficiency and resistance to natural disaster and pests. Despite being the leading residential construction material in Europe and Japan, lumber is the leading material of choice in the ...

  16. On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

    OpenAIRE

    Burcharth, H. F.; Howell, G.L.; Liu, Z.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structural integrity. The paper presents a general discussion of the problems related to stress etermination and describes the results and the analyses of model tests with 200 kg and 200 g load-cell instrume...

  17. Determination of the numerical parameters of a continuous damage model for the structural analysis of clay brick masonry

    Directory of Open Access Journals (Sweden)

    Felipe Barbosa Mangueira

    2012-12-01

    Full Text Available Models based on the continuous damage theory present good responses in representing the nonlinear behavior of reinforced concrete structures with loss of strength and stiffness of the material. However, damage theory is rarely employed in the analysis of masonry structures and numerical simulations are currently performed mostly by Finite Element Method formulations. A computational program was designed to determine the numerical parameters of a damage model of the physical properties of masonry components, solid clay brick and mortar. The model was formulated based on the composition of tensile and compressive surface strengths in the plane stress state. The numerical parameters, the corresponding curves of the activation surfaces and the evolution of the surfaces are presented. The results were fed into the computational program based on the Boundary Element Method (BEM for the simulation of masonry walls, and two types of masonry were simulated. The results confirm the good performance of the model and the program based on the BEM.

  18. Discontinuous modelling of masonry failure

    OpenAIRE

    VANDOREN, Bram

    2013-01-01

    A robust and efficient numerical model is a valuable engineering tool for predicting the load-bearing capacity and failure mode of masonry structures. Such a computational model consists of three key ingredients: a constitutive law which incorporates the non-linear material responses, a kinematic framework for describing failure mechanisms, and a solution algorithm which is capable of modelling the complete loading behaviour of a structure up to total failure. This work focuses on the latter ...

  19. Masonry constructions mechanical models and numerical applications

    CERN Document Server

    Lucchesi, Massimiliano; Padovani, Cristina

    2008-01-01

    Numerical methods for the structural analysis of masonry constructions can be of great value in assessing the safety of artistically important masonry buildings and optimizing potential operations of maintenance and strengthening in terms of their cost-effectiveness, architectural impact and static effectiveness. This monograph firstly provides a detailed description of the constitutive equation of masonry-like materials, clearly setting out its most important features. It then goes on to provide a numerical procedure to solve the equilibrium problem of masonry solids. A large portion of the w

  20. 7 CFR 2902.42 - Wood and concrete sealers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Wood and concrete sealers. 2902.42 Section 2902.42... Items § 2902.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage caused by...

  1. A seismic analysis for masonry constructions: The different schematization methods of masonry walls

    Science.gov (United States)

    Olivito, Renato. S.; Codispoti, Rosamaria; Scuro, Carmelo

    2017-11-01

    Seismic analysis of masonry structures is usually analyzed through the use of structural calculation software based on equivalent frames method or to macro-elements method. In these approaches, the masonry walls are divided into vertical elements, masonry walls, and horizontal elements, so-called spandrel elements, interconnected by rigid nodes. The aim of this work is to make a critical comparison between different schematization methods of masonry wall underlining the structural importance of the spandrel elements. In order to implement the methods, two different structural calculation software were used and an existing masonry building has been examined.

  2. Seismic Performance of Masonry Buildings in Algeria

    OpenAIRE

    F. Lazzali; S. Bedaoui

    2012-01-01

    Structural performance and seismic vulnerability of masonry buildings in Algeria are investigated in this paper. Structural classification of such buildings is carried out regarding their structural elements. Seismicity of Algeria is briefly discussed. Then vulnerability of masonry buildings and their failure mechanisms in the Boumerdes earthquake (May, 2003) are examined.

  3. Retrofitting unreinforced masonry | Ngowi | Botswana Journal of ...

    African Journals Online (AJOL)

    This paper is expected to provide general guidelines to practicing Engineers to assist them in deciding the appropriate alternatives in strengthening unreinforced masonry structures. Key Words: Unreinforced masonry, structural strengthening, Fibre Reinforced Polymer, Earthquake, retrofitting, wind. Botswana Journal of ...

  4. Mechanical Behaviour of the Wood Masonry

    Directory of Open Access Journals (Sweden)

    Fazia FOUCHAL

    2011-09-01

    Full Text Available In this paper we study the walls wood masonry behaviour. First, we propose a regulatory validation of the walls wood masonry behaviour subjected to vertical and horizontal loads according to Eurocode 5. Then we present the numerical application on the wall wood supported two floors level.

  5. Energy Efficiency Improvement and Cost Saving Oportunities for the Concrete Industry

    Energy Technology Data Exchange (ETDEWEB)

    Kermeli, Katerina; Worrell, Ernst; Masanet, Eric

    2011-12-01

    The U.S. concrete industry is the main consumer of U.S.-produced cement. The manufacturing of ready mixed concrete accounts for more than 75% of the U.S. concrete production following the manufacturing of precast concrete and masonry units. The most significant expenditure is the cost of materials accounting for more than 50% of total concrete production costs - cement only accounts for nearly 24%. In 2009, energy costs of the U.S. concrete industry were over $610 million. Hence, energy efficiency improvements along with efficient use of materials without negatively affecting product quality and yield, especially in times of increased fuel and material costs, can significantly reduce production costs and increase competitiveness. The Energy Guide starts with an overview of the U.S. concrete industry’s structure and energy use, a description of the various manufacturing processes, and identification of the major energy consuming areas in the different industry segments. This is followed by a description of general and process related energy- and cost-efficiency measures applicable to the concrete industry. Specific energy and cost savings and a typical payback period are included based on literature and case studies, when available. The Energy Guide intends to provide information on cost reduction opportunities to energy and plant managers in the U.S. concrete industry. Every cost saving opportunity should be assessed carefully prior to implementation in individual plants, as the economics and the potential energy and material savings may differ.

  6. Non Linear Seismic Analysis of Masonry Structures

    Directory of Open Access Journals (Sweden)

    Sirajuddin, M

    2011-12-01

    Full Text Available Nowadays, even though many new construction techniques have been introduced, masonry has got its own importance in building industry. Masonry structures fail miserably under lateral loading conditions like earth quakes and impact loads. The occurrence of recent earthquakes in India and in different parts of the world have highlighted that most of the loss of human lives and damage to property have been due to the collapse of masonry structures. Though an earthquake could not be prevented, the loss of life and property could be minimized, if necessary steps could be taken to reduce the damages on the existing masonry structures. This paper investigates the application ofNonlinear Seismic Analysis of a masonry building using ANSYS software and check the efficacy of retrofit measuresto protect the existing building.

  7. 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...

  8. Collapse Mechanisms Of Masonry Structures

    International Nuclear Information System (INIS)

    Zuccaro, G.; Rauci, M.

    2008-01-01

    The paper outlines a possible approach to typology recognition, safety check analyses and/or damage measuring taking advantage by a multimedia tool (MEDEA), tracing a guided procedure useful for seismic safety check evaluation and post event macroseismic assessment. A list of the possible collapse mechanisms observed in the post event surveys on masonry structures and a complete abacus of the damages are provided in MEDEA. In this tool a possible combination between a set of damage typologies and each collapse mechanism is supplied in order to improve the homogeneity of the damages interpretation. On the other hand recent researches of one of the author have selected a number of possible typological vulnerability factors of masonry buildings, these are listed in the paper and combined with potential collapse mechanisms to be activated under seismic excitation. The procedure takes place from simple structural behavior models, derived from the Umbria-Marche earthquake observations, and tested after the San Giuliano di Puglia event; it provides the basis either for safety check analyses of the existing buildings or for post-event structural safety assessment and economic damage evaluation. In the paper taking advantage of MEDEA mechanisms analysis, mainly developed for the post event safety check surveyors training, a simple logic path is traced in order to approach the evaluation of the masonry building safety check. The procedure starts from the identification of the typological vulnerability factors to derive the potential collapse mechanisms and their collapse multipliers and finally addresses the simplest and cheapest strengthening techniques to reduce the original vulnerability. The procedure has been introduced in the Guide Lines of the Regione Campania for the professionals in charge of the safety check analyses and the buildings strengthening in application of the national mitigation campaign introduced by the Ordinance of the Central Government n. 3362

  9. Collapse Mechanisms Of Masonry Structures

    Science.gov (United States)

    Zuccaro, G.; Rauci, M.

    2008-07-01

    The paper outlines a possible approach to typology recognition, safety check analyses and/or damage measuring taking advantage by a multimedia tool (MEDEA), tracing a guided procedure useful for seismic safety check evaluation and post event macroseismic assessment. A list of the possible collapse mechanisms observed in the post event surveys on masonry structures and a complete abacus of the damages are provided in MEDEA. In this tool a possible combination between a set of damage typologies and each collapse mechanism is supplied in order to improve the homogeneity of the damages interpretation. On the other hand recent researches of one of the author have selected a number of possible typological vulnerability factors of masonry buildings, these are listed in the paper and combined with potential collapse mechanisms to be activated under seismic excitation. The procedure takes place from simple structural behavior models, derived from the Umbria-Marche earthquake observations, and tested after the San Giuliano di Puglia event; it provides the basis either for safety check analyses of the existing buildings or for post-event structural safety assessment and economic damage evaluation. In the paper taking advantage of MEDEA mechanisms analysis, mainly developed for the post event safety check surveyors training, a simple logic path is traced in order to approach the evaluation of the masonry building safety check. The procedure starts from the identification of the typological vulnerability factors to derive the potential collapse mechanisms and their collapse multipliers and finally addresses the simplest and cheapest strengthening techniques to reduce the original vulnerability. The procedure has been introduced in the Guide Lines of the Regione Campania for the professionals in charge of the safety check analyses and the buildings strengthening in application of the national mitigation campaign introduced by the Ordinance of the Central Government n. 3362

  10. Behaviour of masonry structures during the Bhuj earthquake of ...

    Indian Academy of Sciences (India)

    A variety of masonry structures suffered damage during the recent Bhuj earthquake. Some of the traditional masonry structures had no earthquake resistant features and suffered considerable damage. This paper attempts to evaluate the behaviour of masonry structures based on the type of masonry used in places like Bhuj ...

  11. Refiring bricks at 540ºC : Hot masonry and magnetic separation close the brick recycling process

    NARCIS (Netherlands)

    Van Dijk, K; Hendriks, C.; Van der Graaf, A.

    2004-01-01

    For many decades, stony debris from building and demolition sites was reused as road building material. Until recently there was no need to look for other uses for this mixture of concrete and masonry rubble. However, now that our supplies of marl and gravel (two of the three ingredients of mortar

  12. Damage to historic brick masonry structures. Masonry damage diagnostic system and damage atlas for evaluation of deterioration

    NARCIS (Netherlands)

    Balen, K. van; Binda, L.; Hees, R.P.J. van; Franke, L.

    1996-01-01

    The aim of the research on brick masonry degradation supported by the D.G. XII is presented. The project is delivering the following: ► Damage Atlas of ancient brick masonry, a book with a description of the types of damage, and their possible causes, in ancient brick masonry structures; ► Masonry

  13. Silicon micro-masonry using elastomeric stamps for three-dimensional microfabrication

    International Nuclear Information System (INIS)

    Keum, Hohyun; Eisenhaure, Jeffrey D; Kim, Seok; Carlson, Andrew; Ning, Hailong; Mihi, Agustin; Braun, Paul V; Rogers, John A

    2012-01-01

    We present a micromanufacturing method for constructing microsystems, which we term ‘micro-masonry’ based on individual manipulation, influenced by strategies for deterministic materials assembly using advanced forms of transfer printing. Analogous to masonry in construction sites, micro-masonry consists of the preparation, manipulation, and binding of microscale units to assemble microcomponents and microsystems. In this paper, for the purpose of demonstration, we used microtipped elastomeric stamps as manipulators and built three dimensional silicon microstructures. Silicon units of varied shapes were fabricated in a suspended format on donors, retrieved, delivered, and placed on a target location on a receiver using microtipped stamps. Annealing of the assembled silicon units permanently bound them and completed the micro-masonry procedure. (paper)

  14. Suspension of a steam raising unit in a reinforced concrete pressure vessel of a high temperature reactor

    International Nuclear Information System (INIS)

    Schoening, J.; Schwiers, H.G.; Stracke, W.

    1982-01-01

    The invention concerns a supporting device in a steam raising unit, which is situated in the reinforced concrete pressure vessel of a high temperature reactor. The supporting device is situated in the space between the steam raising unit skirt and the steam raising unit jacket. If the suspension of the steam raising unit skirt fails, the steam raising unit skirt is well fixed by the supporting device in the steam raising unit jacket, without the feed water and steam pipes in the upper part of the steam raising unit being damaged. (orig.) [de

  15. CircleBoard-Pro: Concrete manipulative-based learning cycle unit for learning geometry

    Science.gov (United States)

    Jamhari, Wongkia, Wararat

    2018-01-01

    Currently, a manipulative is commonly used in mathematics education as a supported tool for teaching and learning. With engaging natural interaction of a concrete manipulative and advantages of a learning cycle approach, we proposed the concrete manipulative-based learning cycle unit to promote mathematics learning. Our main objectives are to observe possibilities on the use of a concrete manipulative in learning geometry, and to assess students' understanding of a specific topic, angle properties in a circle, of secondary level students. To meet the first objective, the concrete manipulative, called CricleBoard-Pro, was designed. CircleBoard-Pro is built for easy to writing on or deleting from, accurate angle measurement, and flexible movement. Besides, learning activities and worksheets were created for helping students to learn angle properties in a circle. Twenty eighth graders on a lower secondary school in Indonesia were voluntarily involved to learn mathematics using CircleBoard-Pro with the designed learning activities and worksheets. We informally observed students' performance by focusing on criteria of using manipulative tools in learning mathematics while the learning activities were also observed in terms of whether they work and which step of activities need to be improved. The results of this part showed that CircleBoard-Pro complied the criteria of the use of the manipulative in learning mathematics. Nevertheless, parts of learning activities and worksheets need to be improved. Based on the results of the observation, CircleBoard-Pro, learning activities, and worksheets were merged together and became the CircleBoardPro embedded on 5E (Engage - Explore - Explain - Elaborate - Evaluate) learning cycle unit. Then, students understanding were assessed to reach the second objective. Six ninth graders from an Indonesian school in Thailand were recruited to participate in this study. Conceptual tests for both pre-and post-test, and semi

  16. Three growing questions about Masonry

    Directory of Open Access Journals (Sweden)

    Davide Crimi

    2017-07-01

    Full Text Available Through three capital questions, this short essay tries to offer a general panorama and a better understanding of the proteiform complex body or Masonry. Through by a multi-level hermeneutic, this study get the ambition to be comprehensible both to Readers who are not used to this kind of literature and to the ones advanced and skilled in symbolic thought. The main important conclusion owes the quality of the symbolic level, which is the property to refuse a single interpretation: notwithstanding, this does not prevent from a clear historical and political evaluation of the phenomena under analysis, according the methodologies of social sciences. This political evaluability drives to the main valuable output of the essay, which concerns the anthropological statement that the logical label of Masonry, with this name or many others, it exists since always. Under the category of initiatory institution, we may consider the step between individual and society, and a society inside a larger one. Evolving from the needs of the individuals to the ones of social groups, the matter joins to the land of political sciences. The sociological meaning can be posed under analytic view in reason of the functionalist meaning emerging from the alternative couples status-quo/emancipation and conservatism/progressivism. Through by this perspective, anyway the theme seems not to reveal much more, because this “proteiform complex body” manifest itself as something too much complex in its inner core to be considered in a way or in another. What remains is strictly symbolic, with some theological and eschatological points that refuse to be posed under restrain.

  17. Comparison of different approaches of modelling in a masonry building

    Science.gov (United States)

    Saba, M.; Meloni, D.

    2017-12-01

    The present work has the objective to model a simple masonry building, through two different modelling methods in order to assess their validity in terms of evaluation of static stresses. Have been chosen two of the most commercial software used to address this kind of problem, which are of S.T.A. Data S.r.l. and Sismicad12 of Concrete S.r.l. While the 3Muri software adopts the Frame by Macro Elements Method (FME), which should be more schematic and more efficient, Sismicad12 software uses the Finite Element Method (FEM), which guarantees accurate results, with greater computational burden. Remarkably differences of the static stresses, for such a simple structure between the two approaches have been found, and an interesting comparison and analysis of the reasons is proposed.

  18. 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.

  19. Rilem TC 203-RHM: Repair mortars for historic masonry. Requirements for repointing mortars for historic masonry

    NARCIS (Netherlands)

    Hees, R.P.J. van; Groot, C.; Hughes, J.J.; Balen, K. van; Bicer-Simsir, B.; Binda, L.; Elsen, J.; Konow, T. von; Lindqvist, J.E.; Papayanni, I.; Subercaseaux, M.; Tedeschi, C.; Toumbakari, E.E.; Thompson, B.

    2012-01-01

    This paper gives a summary of functional and performance requirements for repointing mortars for historic masonry (design, execution and maintenance). Successful performance of repair and conservation of mortar in historic masonry requires more care with design and execution than with modern

  20. Recent development in blast performance of fiber-reinforced concrete

    Science.gov (United States)

    Hajek, R.; Foglar, M.; Kohoutkova, A.

    2017-09-01

    The paper presents an overview of the recent development in blast performance of fiber reinforced concrete. The paper builds on more than ten years’ history of the research in this field by the team of the Department of Concrete and Masonry Structures of the Faculty of Civil Engineering of the Czech Technical University in Prague.

  1. Vulnerability of historical masonry buildings under exceptional actions

    OpenAIRE

    Florio, Gilda

    2010-01-01

    The topic of this thesis is the vulnerability assessment of historical masonry buildings under exceptional actions. In order to develop the study, the structural performance of masonry aggregates and isolated monumental buildings under extreme loading condition have been investigated.

  2. Degradation of Waterfront Reinforced Concrete Structures

    African Journals Online (AJOL)

    impact , tension, compressive or fatigue cracking, degradation of waterfront structures are caused by mainly ... International, 2002). Corrosion of steel reinforcement contributes greatly to the deterioration of reinforced concrete structures. Corrosion products accompany the .... selected piers and masonry walls have shown a.

  3. THE EVOLUTION OF THE DESIGN AND CONSTRUCTION OF MASONRY BUILDINGS IN AUSTRALIA

    Directory of Open Access Journals (Sweden)

    Adrian Page

    2012-12-01

    Full Text Available Masonry is a construction material which is widely used in Australia in a number of forms (fired clay, concrete, calcium silicate, natural stone, autoclaved aerated concrete and in a wide range of both loadbearing and non-loadbearing applications. As such, it serves as the primary structural element in structures such as 3-4 story “walk up” apartment buildings or low rise commercial structures, or as a veneer or infill in housing or high rise framed construction. Despite its current widespread use, for masonry to remain a viable construction material in the future, design and construction practices need to be flexible, able to adapt to change and be receptive to innovation. This applies not only to advances in materials technology and the development of new products and building systems, but also an effective response to changes in the regulatory framework which have an increasing emphasis on thermal and acoustic performance, seismic resistance and sustainable practices. In this context, an overview of the Australian past, present and possible future masonry scene is given.

  4. STRUCTURAL VULNERABILITY ASSESSMENT OF MASONRY BUILDINGS IN TURKEY

    OpenAIRE

    KORKMAZ, Kasım Armagan; CARHOGLU, Asuman Isıl

    2011-01-01

    Turkey is located in an active seismic zone. Mid to high rise R/C building and low rise masonry buildings are very common construction type in Turkey. In recent earthquakes, lots of existing buildings got damage including masonry buildings. Masonry building history in Turkey goes long years back. For sure, it is an important structure type for Turkey. Therefore, earthquake behavior and structural vulnerability of masonry buildings are crucial issues for Turkey as a earthquake prone country. I...

  5. Mesoscale partitioned analysis of brick-masonry arches

    OpenAIRE

    Zhang, Y; Macorini, L; Izzuddin, BA

    2016-01-01

    ? 2016 Elsevier Ltd.Past research has shown that masonry mesoscale descriptions, where bricks and mortar joints are modelled separately, offer a realistic representation of the mechanical behaviour of masonry components. In the case of masonry arches, thus far the use of this approach has been restricted to 2D analysis mainly because of the significant computational effort required. However conventional 2D models may lead to a crude representation of the response of masonry arches which is in...

  6. Cooling tower, construction method method therefor and precast prestressed concrete building units

    International Nuclear Information System (INIS)

    Lin, T.Y.; Yang, Y.C.

    1978-01-01

    A large, thin-shell cooling tower, a method for its erection, and novel precast units are described. Upon a foundation a series of angularly-extending columns is erected, and the columns are joined at their upper ends by a lower ring. Then a ribbed, waffle-like reinforced concrete wall is constructed to extend up from the lower ring and to provide a shell with a shape such as a hyperbolic paraboloid. The ribbed outer (or inner) surface strengthens the structure while enabling the thickness of the portions in between the ribs to be relatively thin. A series of vertically-spaced horizontal circumferential reinforcing bars or post-tensioning cables and a series of horizontally-spaced vertical or inclined bars or cables are included in the wall. The wall is preferably made up from a series of precast units that are of novel structure in themselves. At the top of the wall is an upper ring joining the various elements together

  7. Strengthening and Rehabilitation Conventional Methods for Masonry Structures

    OpenAIRE

    Pleşu, Raluca; Ţăranu, George; Covatariu, Daniel; Grădinariu, Ionuţ-Dan

    2011-01-01

    The study and development of rehabilitation and strengthening methods for masonry structures is a permanent concern of civil engineers, because of the high proportion of existing structural masonry and their vulnerability to exceptional loads, especially from seismic action. This paper presents an overview of existing methodologies for strengthening and rehabilitation of masonry structures using traditional materials.

  8. 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.)

  9. 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

  10. Masonry structures between mechanics and architecture

    CERN Document Server

    Pedemonte, Orietta; Williams, Kim

    2015-01-01

    This book provides an overview of state of the art research in the mechanics of masonry structures. It continues the series Between Mechanics and Architecture, initially launched in 1995 from the collaboration of several renowned scholars, including Edoardo Benvenuto and Patricia Radelet-de Grave.   The contributions in this volume represent the main approaches to the complex topic of masonry structures. In addition to historical studies, the mechanical behavior of masonry arches and structures is studied using different approaches (structural analysis, limit analysis, elastic analysis, plasticity, mathematical approaches, etc.), at times difficult to reconcile, at others intertwined and complementary.   Readers will have the opportunity to compare different theoretical lines of inquiry and thus explore new horizons of research.   Contributions by: Danila Aita Andrea Bacigalupo Riccardo Barsotti Stefano Bennati Antonio Brencich Mario Como Salvatore D’Agostino Luigi Gambarotta Jacques Heyman Santiago Huer...

  11. Fukushima Daiichi Unit 1 Ex-Vessel Prediction: Core Concrete Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Farmer, Mitchell [Argonne National Lab. (ANL), Argonne, IL (United States); Francis, Matthew W [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Lower head failure and corium concrete interaction were predicted to occur at Fukushima Daiichi Unit 1 (1F1) by several different system-level code analyses, including MELCOR v2.1 and MAAP5. Although these codes capture a wide range of accident phenomena, they do not contain detailed models for ex-vessel core melt behavior. However, specialized codes exist for analysis of ex-vessel melt spreading (e.g., MELTSPREAD) and long-term debris coolability (e.g., CORQUENCH). On this basis, an analysis was carried out to further evaluate ex-vessel behavior for 1F1 using MELTSPREAD and CORQUENCH. Best-estimate melt pour conditions predicted by MELCOR v2.1 and MAAP5 were used as input. MELTSPREAD was then used to predict the spatially dependent melt conditions and extent of spreading during relocation from the vessel. The results of the MELTSPREAD analysis are reported in a companion paper. This information was used as input for the long-term debris coolability analysis with CORQUENCH.

  12. Retrofit of a Multifamily Mass Masonry Building in New England

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Kerrigan, P.; Wytrykowska, H.; Van Straaten, R.

    2013-08-01

    Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The research performed for this project provides information regarding advanced retrofit packages for multi-family masonry buildings in Cold climates. In particular, this project demonstrates safe, durable, and cost-effective solutions that will potentially benefit millions of multi-family brick buildings throughout the East Coast and Midwest (Cold climates). The retrofit packages provide insight on the opportunities for and constraints on retrofitting multifamily buildings with ambitious energy performance goals but a limited budget. The condominium conversion project will contribute to several areas of research on enclosures, space conditioning, and water heating. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection, and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.

  13. Resistance of Membrane Retrofit Concrete Masonry Walls to Lateral Pressure

    Science.gov (United States)

    2008-04-01

    of wall with no openings α Wall support degree of fixity β Ratio of wall curvature Bw Factor for opening in wall c Radius of curvature Δ wall...recognizing all of the relevant design variables (Yokel and Dikkers 1971). Design variables such as loading geometry, end fixity , wall stiffness, and...bottom interfaces. The last assumption is made to help develop the necessary equations for wall failure with varying degrees of end fixity . Although

  14. Compatible dilation limits of masonry joint mortars

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Beran, Pavel

    2010-01-01

    Roč. 4, č. 2 (2010), s. 155-176 ISSN 1558-3058 R&D Projects: GA ČR(CZ) GA103/06/1609 Institutional research plan: CEZ:AV0Z20710524 Keywords : material characteristics * stone masonry * thermal expansion Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 0.500, year: 2010

  15. Analysis of Joint Masonry Moisture Content Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [Building Science Corporation, Westford, MA (United States)

    2015-10-01

    Adding insulation to the interior side of walls of masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw, have known solutions, but wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content & relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100% RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated versus non-insulated joist pockets do not show large differences. South facing joists have safe (10-15%) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

  16. Electrokinetic removal of salt from brick masonry

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul; Rörig-Dalgaard, Inge

    2006-01-01

    A method to effectively remove salts from masonry is lacking. The present study aims at determining the removal efficiency of salts from bricks in an applied low current electric DC field. At first an investigation on removal of NaCl and Na(NO3)2 from spiked bricks in laboratory scale was conducted......, a cathode and an anode, that were placed on a masonry wall of an old stable. The masonry had a high concentration of nitrates and problems with hygroscopic moisture. The electrodes consisted of reinforcement steel in carbonate-rich clay. The clay was chosen mainly to improve electric contact between metal...... the highest initial concentrations in the masonry. The second pilot-test with a new set of electrodes is running at present. Current have been applied to these electrodes for 35 days in very cold weather (most of the time below 0ºC) which shows that the method can be used during periods with frost....

  17. ASSESSMENT OF THE ASR EXPANSION OF CONCRETE MADE WITH RECYCLED CONCRETE AGGREGATES

    OpenAIRE

    Boehme, Luc; Joseph, Miquel

    2016-01-01

    The amount of construction and demolition waste is increasing all over the world. Most of this waste consists of concrete and masonry. These waste materials are very suitable to be recycled. After carrying out an advanced recycling procedure, it’s possible to produce highquality recycled aggregates. Until now, most of these aggregates are used in low grade application as in road foundations. In Flanders, where the market in road works is now almost saturated, using more recycled concrete aggr...

  18. 29 CFR 1926.854 - Removal of walls, masonry sections, and chimneys.

    Science.gov (United States)

    2010-07-01

    ..., girders, and similar structural supports shall be cleared of all loose material as the masonry demolition... 29 Labor 8 2010-07-01 2010-07-01 false Removal of walls, masonry sections, and chimneys. 1926.854....854 Removal of walls, masonry sections, and chimneys. (a) Masonry walls, or other sections of masonry...

  19. Analysis of Joist Masonry Moisture Content Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [Building Science Corporation, Westford, MA (United States)

    2015-10-08

    There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw have known solutions. But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content & relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100% RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated vs. non-insulated joist pockets do not show large differences. South facing joists have safe (10-15%) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

  20. Numerical Models for the Assessment of Historical Masonry Structures and Materials, Monitored by Acoustic Emission

    Directory of Open Access Journals (Sweden)

    Stefano Invernizzi

    2016-04-01

    Full Text Available The paper reviews some recent numerical applications for the interpretation and exploitation of acoustic emission (AE monitoring results obtained from historical masonry structures and materials. Among possible numerical techniques, the finite element method and the distinct method are considered. The analyzed numerical models cover the entire scale range, from microstructure and meso-structure, up to full-size real structures. The micro-modeling includes heterogeneous concrete-like materials, but mainly focuses on the masonry texture meso-structure, where each brick and mortar joint is modeled singularly. The full-size models consider the different typology of historical structures such as masonry towers, cathedrals and chapels. The main difficulties and advantages of the different numerical approaches, depending on the problem typology and scale, are critically analyzed. The main insight we can achieve from micro and meso numerical modeling concerns the scaling of AE as a function of volume and time, since it is also able to simulate the b-value temporal evolution as the damage spread into the structure. The finite element modeling of the whole structure provides useful hints for the optimal placement of the AE sensors, while the combination of AE monitoring results is crucial for a reliable assessment of structural safety.

  1. Failure Criterion for Brick Masonry: A Micro-Mechanics Approach

    OpenAIRE

    Kawa Marek

    2015-01-01

    The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading ...

  2. Measure Guideline: Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F.; Ueno, K.; Schumacher, C. J.

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  3. Measure Guideline. Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F. [Building Science Corporation (BSC), Somerville, MA (United States); Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Schumacher, C. J. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  4. Seismic fragility evaluation of unreinforced masonry walls

    International Nuclear Information System (INIS)

    Park, Y.J.; Hofmayer, C.H.; Reich, M.; Lee, S.K.

    1991-01-01

    A practical analysis scheme to evaluate the seismic fragility of unreinforced masonry walls which are used at various places in older reactor facilities is presented. Among the several failure modes for such walls, the out-of-plane bending failure is considered to be a major risk contributor in seismic PRA studies. In order to evaluate this failure mode, the use of an equivalent linear approximation method is examined based on comparisons with available test data and nonlinear time history analyses. (author)

  5. The Structural Rehabilitation of a Masonry Building

    OpenAIRE

    Pop, Ioan; Cobîrzan, Nicoleta

    2013-01-01

    The paper presents a structural rehabilitation system for the basement of a strongly damaged building having the walls, columns, arches and cylindrical vaults of brick masonry. As a consequence of deterioration due to humidity presence in the basement, the columns sections were diminished substantially to about 25%...30% of their initial section, the building being in this way very sensitive to collapse. The intervention solution was chosen on financial criteria, and the final purposes it was...

  6. On the dynamics of viscous masonry beams

    Czech Academy of Sciences Publication Activity Database

    Lucchesi, M.; Pintucchi, B.; Šilhavý, Miroslav; Zani, N.

    2015-01-01

    Roč. 27, č. 3 (2015), s. 349-365 ISSN 0935-1175 R&D Projects: GA ČR GA201/09/0473 Institutional support: RVO:67985840 Keywords : non-linear dynamics * no-tension material * masonry slender towers and arches * coupling phenomena * Galerkin method Subject RIV: BA - General Mathematics Impact factor: 1.849, year: 2015 http://link.springer.com/article/10.1007%2Fs00161-014-0352-y

  7. Development of an unfired clay masonry system

    OpenAIRE

    Fourie, Clyde

    2012-01-01

    An unfired clay masonry system complete with renders and fixings was required for the mainstream construction of thin non-load bearing inner leaf or interior walls in domestic dwellings. A determined movement to reduce the impact the building sector has on the environment aims to incorporate natural materials such as earth, animal products and vegetable matter into the development of building products for the construction of domestic dwellings to produce sustainable modern buildings with mini...

  8. Reinforcing masonry walls with composite materials

    Science.gov (United States)

    Jai, John Chia-Han

    1999-10-01

    In this investigation, a procedure is developed for determining the effectiveness of composite materials in retrofitting masonry buildings to reduce seismic damage. The reinforcement considered is a thin layer of fiber-reinforced composite applied to the wall in a wallpaper-like fashion. Models were developed which predicts the behavior of masonry walls reinforced in such a fashion and subjected to static, in-plane normal and shear loads. Solid walls, as well as walls with openings (such as windows and doors), were considered. The models estimate the load-deflection characteristic of the wall, the load set at which the wall fails, and the deflection of the wall at the instant of failure. The models were verified by tests performed with walls constructed of clay bricks and mortar, and with walls made of wood bricks. In these tests, the load versus deflection, the failure load, and the failure deflection were measured. Reasonable agreements were found between the values calculated by the models and the data. Parametric studies were also performed. The results of these studies indicate that composite reinforcement applied in a wallpaper-like fashion may increase substantially the load carrying capacities of masonry walls.

  9. Seismic Safety Of Simple Masonry Buildings

    International Nuclear Information System (INIS)

    Guadagnuolo, Mariateresa; Faella, Giuseppe

    2008-01-01

    Several masonry buildings comply with the rules for simple buildings provided by seismic codes. For these buildings explicit safety verifications are not compulsory if specific code rules are fulfilled. In fact it is assumed that their fulfilment ensures a suitable seismic behaviour of buildings and thus adequate safety under earthquakes. Italian and European seismic codes differ in the requirements for simple masonry buildings, mostly concerning the building typology, the building geometry and the acceleration at site. Obviously, a wide percentage of buildings assumed simple by codes should satisfy the numerical safety verification, so that no confusion and uncertainty have to be given rise to designers who must use the codes. This paper aims at evaluating the seismic response of some simple unreinforced masonry buildings that comply with the provisions of the new Italian seismic code. Two-story buildings, having different geometry, are analysed and results from nonlinear static analyses performed by varying the acceleration at site are presented and discussed. Indications on the congruence between code rules and results of numerical analyses performed according to the code itself are supplied and, in this context, the obtained result can provide a contribution for improving the seismic code requirements

  10. 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.

  11. Thermographic inspection of bond defects in Fiber Reinforced Polymer applied to masonry structures

    Science.gov (United States)

    Masini, N.; Aiello, M. A.; Capozzoli, L.; Vasanelli, E.

    2012-04-01

    Nowadays, externally bonded Fiber Reinforced Polymers (FRP) are extensively used for strengthening and repairing masonry and reinforced concrete existing structures; they have had a rapid spread in the area of rehabilitation for their many advantages over other conventional repair systems, such as lightweight, excellent corrosion and fatigue resistance, high strength, etc. FRP systems applied to masonry or concrete structures are typically installed using a wet-layup technique.The method is susceptible to cause flaws or defects in the bond between the FRP system and the substrate, which may reduce the effectiveness of the reinforcing systems and the correct transfer of load from the structure to the composite. Thus it is of primary importance to detect the presence of defects and to quantify their extension in order to eventually provide correct repair measurements. The IR thermography has been cited by the several guidelines as a good mean to qualitatively evaluate the presence of installation defects and to monitor the reinforcing system with time.The method is non-destructive and does not require contact with the composite or other means except air to detect the reinforcement. Some works in the literature have been published on this topic. Most of the researches aim at using the IR thermography technique to characterize quantitatively the defects in terms of depth, extension and type in order to have an experimental database on defect typology to evaluate the long term performances of the reinforcing system. Nevertheless, most of the works in the literature concerns with FRP applied to concrete structures without considering the case of masonry structures. In the present research artificial bond defects between FRP and the masonry substrate have been reproduced in laboratory and the IR multi temporal thermography technique has been used to detect them. Thermographic analysis has been carried out on two wall samples having limited dimensions (100 x 70 cm) both

  12. Mechanical characterization and force-displacement hysteretic curves from in-plane cyclic tests on strong masonry infills

    Directory of Open Access Journals (Sweden)

    Paolo Morandi

    2018-02-01

    Full Text Available This article contains information related to a recent study “Performance-based interpretation of in-plane cyclic tests on RC frames with strong masonry infills” (Morandi et al., 2017 [1]. Motivated by the necessity to improve the knowledge of the in-plane seismic response of rigid strong masonry infills, a wide experimental campaign based on in-plane cyclic tests on full-scale RC infilled frame specimens, supplemented with a complete characterization of the materials, has been conducted at the laboratory of the Department of Civil Engineering and Architecture of the University of Pavia. The masonry is constituted by vertically perforated 35 cm thick clay units with tongue and groove and dry head-joints and general-purpose mortar bed-joints. The paper reports the results of the mechanical characterization and of the force-displacement hysteretic curves from the in-plane cyclic tests.

  13. Mechanical characterization and force-displacement hysteretic curves from in-plane cyclic tests on strong masonry infills.

    Science.gov (United States)

    Morandi, Paolo; Hak, Sanja; Magenes, Guido

    2018-02-01

    This article contains information related to a recent study "Performance-based interpretation of in-plane cyclic tests on RC frames with strong masonry infills" (Morandi et al., 2017 [1]). Motivated by the necessity to improve the knowledge of the in-plane seismic response of rigid strong masonry infills, a wide experimental campaign based on in-plane cyclic tests on full-scale RC infilled frame specimens, supplemented with a complete characterization of the materials, has been conducted at the laboratory of the Department of Civil Engineering and Architecture of the University of Pavia. The masonry is constituted by vertically perforated 35 cm thick clay units with tongue and groove and dry head-joints and general-purpose mortar bed-joints. The paper reports the results of the mechanical characterization and of the force-displacement hysteretic curves from the in-plane cyclic tests.

  14. Alteration of uraniferous and native copper concretions in the Permian mudrocks of south Devon, United Kingdom

    International Nuclear Information System (INIS)

    Milodowski, A.E.; Styles, M.T.; Horstwood, M.S.A.; Kemp, S.J.

    2002-03-01

    This report presents the results of a study of the mineralogy and alteration characteristics of unusual concretions containing sheets of native copper, and uranium-vanadium mineralised concretions, in mudstones and siltstones of the Pennian Littleham Mudstone Formation, at Littleham Cove, south Devon, England. The main objectives of the study were: 1. To investigate the corrosion characteristics of the native copper as a natural analogue for the long-term behaviour of copper canisters, sealed in a compacted clay (bentonite) backfill, that will be used for the deep geological disposal of spent fuel and high-level radioactive waste (HLW). This study developed from an earlier pilot study, which demonstrated that the alteration of the native copper in the concretions from Littleham Cove was mineralogically and chemically complex. 2. To investigate the alteration and oxidation of minerals containing reduced species (e.g. ferrous iron) within the uranium-rich concretions as a natural analogue for the potential effects of oxidation induced by alpha-radiolysis of water in a HLW repository environment. Native copper-bearing concretions in the Littleham Mudstone Formation are very rare. They occur, as thin lenticular disks developed largely along bedding lamina and thin low-angle fractures cutting the bedding laminae the upper part of the formation, about 10 m below the top of the formation. This part of the sequence comprises laterally discontinuous, fine-grained sheet-flood and channel sandstones and siltstones. Some of these sandstones, are more extensively-cemented by copper sulphides (mainly chalcocite), copper arsenides, cobalt-nickel arsenides, and uranium silicate. The thin permeable sandstones and siltstones, and fractures zones around small faults appear to have acted as the conduits for the movement of mineralising fluids through the mudstones. The native copper sheets all show a similar pattern of corrosion and alteration. However, the intensity of alteration is

  15. Fiber Reinfoced Polymer Used for Flooding Protection of Engineering Structures Made of RC and Brick Masonry

    Directory of Open Access Journals (Sweden)

    Gabriel Oprişan

    2008-01-01

    Full Text Available Urban and rural floods are becoming nowadays a frequent problem to be dealt with, by both the population and the authorities. Floods and flood related natural disasters act against the civil, industrial and agricultural structures by the hydrostatic and hydrodynamic pressures of water. A set of protective solutions based on Fiber Reinforced Polymer (FRP composite materials, for structural elements of buildings subjected to flood loadings, is proposed and analysed. These solutions are achieved by using the hand lay-up forming technique utilizing glass, carbon or aramid fibers fabrics pre-impregnated with thermosetting epoxy, polyester or vynilester resins. The application of these FRP composites is carried out on reinforced concrete columns and beams as well as on brick masonry works aiming to increase in the overall load bearing capacity, especially against horizontal loads. An improved protection against excessive humidity is also envisaged. The Finite Elements Method based LUSAS software was used to simulate a partially flooded structure. The numerical modeling was carried out in both the un-strengthened and strengthened conditions of the structure in order to assess the increasing in load and deformation capacities of the structural elements. Volumetric finite elements were used for modeling the concrete and masonry members.

  16. Behaviour of masonry structures during the Bhuj earthquake of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    2001-01-26

    Jan 26, 2001 ... 3Senior Scientific Officer, Department of Civil Engineering, Indian Institute of Science, Bangalore 560 012, India. A variety of masonry structures suffered damage during the recent Bhuj earthquake. Some of the traditional masonry structures had no earthquake resistant features and suffered considerable.

  17. Characterizing the Material Properties of Dutch Unreinforced Masonry

    NARCIS (Netherlands)

    Jafari, S.; Rots, J.G.; Esposito, R.; Messali, F.

    2017-01-01

    In the northern part of the Netherlands, The recent seismic activities have raised concerns about the behavior of unreinforced masonry structures which were not designed and constructed to resist seismic loading. The first step towards assessment of seismic behavior of masonry structures is to

  18. Recycled construction debris as an aggregates. Production of concrete blocks

    OpenAIRE

    Sousa, J. G. G.; Bauer, E.; Sposto, R. M.

    2003-01-01

    This paper analyzes the use of recycled construction and demolition debris as aggregate for the construction of concrete blocks to be used in sealing masonry. Initial studies addressed the definition of parameters used in the mix of conventional materials (traditionally used in the production of concrete blocks), involving cylindrical test specimens (100x200 mm), molded with the help of a vibratory table. In addition to these definitions, and based on the mixes showing the best results, a new...

  19. Low cost friction seismic base-isolation of residential new masonry buildings in developing countries: A small masonry house case study

    Science.gov (United States)

    Habieb, A. B.; Milani, G.; Tavio, T.; Milani, F.

    2017-07-01

    A Finite element model was established to examine performance of a low-cost friction base-isolation system in reducing seismic vulnerability of rural buildings. This study adopts an experimental investigation of the isolation system which was conducted in India. Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ in static and dynamic friction coefficient obtained through previous research. The FE model was performed based on a macroscopic approach and the masonry wall is assumed as an isotropic element. In order to observe structural response of the masonry house, elastic and plastic parameters of the brick wall were studied. Concrete damage plasticity (CDP) model was adopted to determine non-linear behavior of the brick wall. The results of FE model shows that involving these friction isolation systems could much decrease response acceleration at roof level. It was found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is there was no damage appearing in systems with friction isolation during the test. Meanwhile a severe failure was clearly visible for a system without isolation.

  20. Compressive strength of brick masonry made with weak mortars

    DEFF Research Database (Denmark)

    Pedersen, Erik Steen; Hansen, Klavs Feilberg

    2013-01-01

    in the joint will ensure a certain level of load-carrying capacity. This is due to the interaction between compression in the weak mortar and tension in the adjacent bricks. This paper proposes an expression for the compressive strength of masonry made with weak lime mortars (fm... (fm≈6 N/mm2) compression tests of masonry with perforated bricks show that the EC6 expression is not always safe for Danish masonry. This is probably because the tensile strength of the bricks also has an effect on the compressive strength of masonry when the mortar is stronger than weak lime mortar......The use of weak mortar has a number of advantages (e.g. prevention of expansion joints, environmental issues). However, according to EC6, the strength of masonry vanishes when the compressive strength of the mortar approaches zero. In reality the presence of even unhardened mortar kept in place...

  1. Alteration of uraniferous and native copper concretions in the Permian mudrocks of south Devon, United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Styles, M.T.; Horstwood, M.S.A.; Kemp, S.J. [British Geological Survey, Nottingham (United Kingdom)

    2002-03-01

    This report presents the results of a study of the mineralogy and alteration characteristics of unusual concretions containing sheets of native copper, and uranium-vanadium mineralised concretions, in mudstones and siltstones of the Pennian Littleham Mudstone Formation, at Littleham Cove, south Devon, England. The main objectives of the study were: 1. To investigate the corrosion characteristics of the native copper as a natural analogue for the long-term behaviour of copper canisters, sealed in a compacted clay (bentonite) backfill, that will be used for the deep geological disposal of spent fuel and high-level radioactive waste (HLW). This study developed from an earlier pilot study, which demonstrated that the alteration of the native copper in the concretions from Littleham Cove was mineralogically and chemically complex. 2. To investigate the alteration and oxidation of minerals containing reduced species (e.g. ferrous iron) within the uranium-rich concretions as a natural analogue for the potential effects of oxidation induced by alpha-radiolysis of water in a HLW repository environment. Native copper-bearing concretions in the Littleham Mudstone Formation are very rare. They occur, as thin lenticular disks developed largely along bedding lamina and thin low-angle fractures cutting the bedding laminae the upper part of the formation, about 10 m below the top of the formation. This part of the sequence comprises laterally discontinuous, fine-grained sheet-flood and channel sandstones and siltstones. Some of these sandstones, are more extensively-cemented by copper sulphides (mainly chalcocite), copper arsenides, cobalt-nickel arsenides, and uranium silicate. The thin permeable sandstones and siltstones, and fractures zones around small faults appear to have acted as the conduits for the movement of mineralising fluids through the mudstones. The native copper sheets all show a similar pattern of corrosion and alteration. However, the intensity of alteration is

  2. How Concrete Is Concrete?

    Science.gov (United States)

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  3. Seismic fragility evaluation of unreinforced masonry walls

    International Nuclear Information System (INIS)

    Park, Y.J.; Hofmayer, C.H.; Reich, M.; Lee, S.K.

    1991-01-01

    A practical analysis scheme to evaluate the seismic fragility of unreinforced masonry walls which are used to various places in older reactor facilities is presented. Among the several failure modes for such walls, the out-of-plane bending failure is considered to be a major risk contributor in seismic PRA studies. In order to evaluate this failure mode, the use of an equivalent linear approximation method is examined based on comparisons with available test data and nonlinear time history analyses. 6 refs., 4 figs., 3 tabs

  4. Repair mortars for historic masonry : Effects of the binder choice on durability

    NARCIS (Netherlands)

    Groot, C.J.W.P.

    2016-01-01

    Factors affecting the design of repair mortars for historic masonry are: the type of masonry, the condition of the masonry and the exposure conditions. Especially in case of low-strength masonry exposed to heavy rain and high salt contents the design of a repair mortar may be a challenge. The most

  5. The influence of materials characteristics and workmanship on rain penetration in historic fired clay brick masonry

    NARCIS (Netherlands)

    Groot, C.J.W.P.; Gunneweg, J.T.M.

    2010-01-01

    Moisture is a major source of damage in historic solid masonry. Therefore, control of moisture movement in masonry is instrumental to the durability of masonry buildings. From research and practical experience it is known that many factors may play a role regarding permeability problems in masonry.

  6. Numerical modelling of forces, stresses and breakages of concrete armour units

    NARCIS (Netherlands)

    Latham, John Paul; Xiang, Jiansheng; Anastasaki, Eleni; Guo, Liwei; Karantzoulis, Nikolaos; Viré, A.C.; Pain, Christopher

    2014-01-01

    Numerical modelling has the potential to probe the complexity of the interacting physics of rubble mound armour systems. Through forward modelling of armour unit packs, stochastic variables such as unit displacement and maximum contact force per unit during an external oscillatory disturbance can

  7. Modeling the thermal characteristics of masonry mortar containing recycled materials

    Science.gov (United States)

    Laney, Morgan Gretchen

    As the building industry in the United States rapidly expands, the reuse of recycled demolition waste aggregates is becoming increasingly more important. Currently, the building industry is the largest consumer of natural resources. The constant use of raw virgin aggregate is resulting in depleting resources, lack of space for landfills, increasing costs, and heightened levels of pollution. The use of these recycled aggregates in building envelopes and the study of thermal properties are becoming a popular area of research in order to improve building energy usage. The construction of Zero Energy Buildings (ZEB) is encouraged by the United States government as a result of the unresolved finite resources and environmental pollution. The focus of this research is on the impact of using recycled demolition waste aggregates on thermal properties, including specific heat capacity and thermal conductivity, in masonry mortar applications. The new forms of aggregate were analyzed for efficiency and practical utilization in construction in seven locations across the United States by embedding the new material into the building envelope of a strip mall mercantile build model from the National Renewable Energy Laboratory (NREL) in the EnergyPlus Building Energy Simulation Program (BESP). It was determined that the recycled aggregate mortar mixtures performed as well as or better than the traditional mortar mix. Opportunities for future research in recycled aggregate mortar mixtures exist in a regional analysis, a regional recycled aggregate cost analysis, and a life cycled cost analysis (LCCA).

  8. Structural Identification And Seismic Analysis Of An Existing Masonry Building

    International Nuclear Information System (INIS)

    Del Monte, Emanuele; Galano, Luciano; Ortolani, Barbara; Vignoli, Andrea

    2008-01-01

    The paper presents the diagnostic investigation and the seismic analysis performed on an ancient masonry building in Florence. The building has historical interest and is subjected to conservative restrictions. The investigation involves a preliminary phase concerning the research of the historic documents and a second phase of execution of in situ and laboratory tests to detect the mechanical characteristics of the masonry. This investigation was conceived in order to obtain the 'LC2 Knowledge Level' and to perform the non-linear pushover analysis according to the new Italian Standards for seismic upgrading of existing masonry buildings

  9. Analysis of rotational and sliding collapse modes of masonry arches via Durand-Claye's method

    Science.gov (United States)

    Barsotti, Riccardo; Aita, Danila; Bennati, Stefano

    2017-11-01

    In this paper the mechanical behavior of circular and pointed masonry arches subject to their own weight is examined in order to determine their collapse modes. Different arch's shapes and thicknesses are considered; the influence of the friction coefficient on the arch collapse is analyzed as well. The safety level of arches is investigated by suitably reworking in semi-analytical form the stability area graphical method proposed by a renowned 19th century French scholar, Durand-Claye. Our analysis enables accounting for any given eccentricity of the thrust at the crown; furthermore, also the strength of masonry is taken into account. According to Durand-Claye's method, the arch is safe if along any given joint both the bending moment and the shear force do not exceed some given limit values. It is shown that attainment of a limit condition according to Durand-Claye corresponds to the onset of a collapse mechanism characterized by either relative rotation or sliding between masonry units. All possible symmetric collapse modes for an arch are thoroughly described. As it was expected, pointed and circular arches show different collapse behaviors. Limit values of arch thickness and friction coefficient are assessed. The results obtained are compared with those given by Michon in 1857.

  10. Timbered masonry for earthquake resistance in Europe

    Directory of Open Access Journals (Sweden)

    Dutu, A.

    2012-12-01

    Full Text Available Europe is a continent that is subject to significant seismic activity. Thus, the buildings’ seismic behaviour must be analysed, including not only the new structures, designed under more rigorous codes, but also older ones. This article examines a traditional type of building that uses timber frame/masonry, which is found in Portugal, Turkey, France, England, Greece, Romania, Italy, Spain, Germany and Scandinavia. Although the structures differ in terms of construction details, their structural system is basically the same: the wooden structural system bears mainly the horizontal loads while the masonry supports the gravity loads. The study includes a brief report on the seismicity of each country where this traditional type of building made of timbered framed masonry is found, together with the description of these buildings’ constructive systems.

    Europa es un continente que está sujeto a una significativa actividad sísmica. Por esta razón, se debe analizar el comportamiento sísmico, no sólo de las nuevas estructuras, diseñadas sobre la base de códigos más exigentes, sino también de los diversos tipos de estructuras antiguas. En este artículo se analizan las estructuras constituidas por mampostería y madera, que se pueden encontrar en Portugal, Turquía, Francia, Inglaterra, Grecia, Rumania, Italia, España, Alemania y Escandinavia. Aunque estas estructuras presentan diferencias en cuanto a detalles constructivos, su sistema estructural es idéntico: el sistema estructural de madera absorbe principalmente las cargas horizontales, mientras que la mampostería garantiza la resistencia a la acción de la gravedad. El estudio presentado incluye un breve informe acerca de la sismicidad de los países en que existe el tipo de construcción mencionado, conjuntamente con la descripción de los sistemas constructivos específicos de cada país.

  11. Behavior of fiber reinforced mortar joints in masonry walls subjected to in-plane shear and out-of-plane bending

    Science.gov (United States)

    Armwood, Catherine K.

    In this project, 26 fiber-reinforced mortar (FRM) mixtures are evaluated for their workability and strength characteristics. The specimens tested include two control mixtures and 24 FRMs. The mixtures were made of two types of binders; Type N Portland cement lime (Type N-PCL) and Natural Hydrated Lime 5 (NHL5); and 6 fiber types (5 synthetic fibers and one organic). When tested in flexure, the results indicate that majority of the synthetic fiber mixtures enhanced the performance of the mortar and the nano-nylon and horse hair fibers were the least effective in improving the mortar's modulus of rupture, ductility, and energy absorption. Four FRMs that improved the mortar's mechanical properties most during the flexural strength test were then used to conduct additional experiments. The FRM's compressive strength, as well as flexural and shear bond strength with clay and concrete masonry units were determined. Those four mixtures included Type N-PCL as the binder and 4 synthetic fibers. They were evaluated at a standard laboratory flow rate of 110% +/- 5% and a practical field flow rate of 130% +/- 5%. Results indicate that the use of fibers decreases the compressive strength of the mortar most of the time. However, the bond strength test results were promising: 81% of the FRM mixtures increased the flexural bond strength of the prism. The mixtures at 110 +/- 5% flow rate bonded better with concrete bricks and those ate 130+/-5% flow rate bonded better with clay bricks. The results of the shear bond strength show 50% of the FRM mixtures improved the shear bond strength. The FRM mixtures at 110+/-5% flow rate bonded with clay units provided the most improvement in shear bond strength compared to control specimen results. Along with detailed discussions and derived conclusions of these experiments, this dissertation includes recommendations for the most feasible FRM for different applications.

  12. Phase-change materials in masonry construction

    Science.gov (United States)

    Lang, M.

    1982-01-01

    A demonstration project leading to commercialization of a passive thermal wall using phase change storage materials (PCM) in masonry construction is reported. Techniques of vacuum forming have been identified and characterized making it possible to produce high-volume low-cost packages for insertion into the core of cement blocks. PCM filled packages with aluminum laminated film produces a long life product capable of operating to store and release solar heat over long periods of time. Accelerated tests indicate operability over the life of the building. Five hundred accelerated test cycles have shown insignificant deterioration of capacity of the phase change material. The testing program shows that the wall is capable of both storing and transmitting heat in a similar manner to conventional trombe walls, but with increased thermal capability. Product cost data on return on investment estimates are low enough to be economically attractive.

  13. Seismic Response Of Masonry Plane Walls: A Numerical Study On Spandrel Strength

    International Nuclear Information System (INIS)

    Betti, Michele; Galano, Luciano; Vignoli, Andrea

    2008-01-01

    The paper reports the results of a numerical investigation on masonry walls subjected to in-plane seismic loads. This research aims to verify the formulae of shear and flexural strength of masonry spandrels which are given in the recent Italian Standards. Seismic pushover analyses have been carried out using finite element models of unreinforced walls and strengthened walls introducing reinforced concrete (RC) beams at the floor levels. Two typologies of walls have been considered distinguished for the height to length ratio h/l of the spandrels: a) short beams (h/l = 1.33) and b) slender beams (h/l = 0.5). Results obtained for the unreinforced and the strengthened walls are compared with equations for shear and flexural strength provided in Standards [1]. The numerical analyses show that the reliability of these equations is at least questionable especially for the prediction of the flexural strength. In the cases in which the axial force has not been determined by the structural analysis, Standards seems to overestimate the flexural strength of short spandrels both for the unreinforced and the strengthened wall

  14. Strengthening masonry infill panels using engineered cementitious composites

    DEFF Research Database (Denmark)

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

    2015-01-01

    This comprehensive experimental study aims at investigating the behavior of masonry infill panels strengthened by fiber reinforced engineered cementitious composites (ECC). The experimental program included testing of materials, masonry elements and panels. Material tests were carried out first...... for ECC in order to assess its distinctive mechanical properties such as tensile stress–strain behavior and multiple cracking. To investigate the influence of a thin layer of ECC on plain masonry in terms of changes in stiffness, strength, and deformability, small scale tests have been conducted...... on masonry elements. Finally, a total of 10 brick panels including two control specimens and eight specimens with different ECC-strengthening configuration were selected. The specimens were subjected to diagonal compression loading under displacement control to evaluate their in-plane deformation...

  15. Analysis of Brick Masonry Wall using Applied Element Method

    Science.gov (United States)

    Lincy Christy, D.; Madhavan Pillai, T. M.; Nagarajan, Praveen

    2018-03-01

    The Applied Element Method (AEM) is a versatile tool for structural analysis. Analysis is done by discretising the structure as in the case of Finite Element Method (FEM). In AEM, elements are connected by a set of normal and shear springs instead of nodes. AEM is extensively used for the analysis of brittle materials. Brick masonry wall can be effectively analyzed in the frame of AEM. The composite nature of masonry wall can be easily modelled using springs. The brick springs and mortar springs are assumed to be connected in series. The brick masonry wall is analyzed and failure load is determined for different loading cases. The results were used to find the best aspect ratio of brick to strengthen brick masonry wall.

  16. Masonry Bearing and Shear Walls Retrofitted With Overlay Composite Material

    National Research Council Canada - National Science Library

    Al-Chaar, Ghassan

    1998-01-01

    ...) switch-house structures have been found to be vulnerable to earthquakes. One technique to reduce the seismic vulnerability of these structures is to retrofit the masonry walls using the Hexcel-Fyfe TYFO(TM) system...

  17. Comparison of the design rules for the end of the prestressed concrete double tee component between China and the United States

    Directory of Open Access Journals (Sweden)

    Meng Xian Hong

    2016-01-01

    Full Text Available Precast prestressed concrete double tee is an economic bearing component which can be made into a large span, large coverage area .From the angle of the design for the end of the precast prestressed concrete double tee component, flexure and axial tension in extended end, direct shear, diagonal tension at re-entrant corner, diagonal tension in extended end and the connection of the end of precast prestressed double tee component in China and the United States are compared. The comparative study provide the direction for the future development of China in the double tee,including strengthening the end reinforcement and increasing end connections.

  18. Strengthening Masonry Arches with Lime-Based Mortar Composite

    Directory of Open Access Journals (Sweden)

    Valerio Alecci

    2017-06-01

    Full Text Available In recent decades, many strengthening interventions on masonry elements were performed by using fiber reinforced polymers (FRPs. These advanced materials proved to be effective to increase the load-carrying capacity of masonry elements and to improve their structural behavior, avoiding the most critical failure modes. Despite the advantages of this technique compared to more traditional methods, FRP systems have disadvantages related to their low resistance to high temperatures, impossibility of application on wet surfaces, low permeability, and poor compatibility with masonry supports. Therefore, composite materials made of a fiber textile embedded in an inorganic matrix were recently proposed as alternatives to FRPs for strengthening historic masonry constructions. These composite materials are easier to install, have higher resistance to high temperatures, and permit higher vapor permeability than FRPs. The inorganic matrix is frequently a cement-based mortar, and the composite materials made of a fiber textile embedded in a cement-based mortar are usually identified as FRCM (fabric reinforced cementitious matrix composites. More recently, the use of natural lime mortar as an inorganic matrix has been proposed as an alternative to cement-based mortars when historic compatibility with the substrate is strictly required, as in case of restoration of historic buildings. In this paper, the effectiveness of a fabric made of basalt fibers embedded in lime mortar matrix (Basalt-FRLM for the strengthening of masonry arches is investigated. An experimental investigation was performed on 1:2 scaled brick masonry arches strengthened at the extrados with a layer of Basalt-FRLM and tested under vertical load. The results obtained are compared with previous results obtained by the authors by testing masonry arches strengthened at their extrados with FRCM and FRP composites. This investigation highlights the effectiveness of Basalt-FRLM in increasing load

  19. Innovative retrofitting materials for brick masonry infill walls

    OpenAIRE

    Mora Gómez, Juan

    2012-01-01

    Dissertação de mestrado em Structural Analysis of Monuments and Historical Constructions Last seismic events in Southern Europe have highlighted the vulnerability in the most usual constructive typology in contemporary architecture: framed structures with masonry infills. Contemporary structures have a good capacity to withstand these actions, given that they were considered for their design according to modern codes. Nonetheless, nonstructural elements as masonry infills show ...

  20. Complete experimental characterization of lime mortar and clay brick masonry

    OpenAIRE

    Pelà, Luca; Canella, Elisa; Kasioumi, Konstantina; Roca Fabregat, Pedro; Marastoni, Diego

    2016-01-01

    This work investigates the mechanical behaviour of lime mortar and clay brick masonry by presenting the results of a comprehensive experimental program carried out in the laboratory. Different kinds of masonry samples were built using either aerial or moderately hydraulic lime mortar. Different tests were carried out to evaluate the compression and shear behaviour of the composite material and its constituents. An important contribution of the research is, besides the presentation of the o...

  1. STRUCTURAL SOLUTIONS AND SPECIAL FEATURES OF THE THERMAL PROTECTION ANALYSIS OF EXTERIOR WALLS OF BUILDINGS MADE OF AUTOCLAVED GAS-CONCRETE BLOCKS

    Directory of Open Access Journals (Sweden)

    Bedov Anatolij Ivanovich

    2012-10-01

    Full Text Available Relevant structural solutions, physical and mechanical characteristics, coefficients of thermal conductivity for exterior masonry walls made of autoclaved gas-concrete blocks are provided in the article. If a single-layer wall is under consideration, an autoclaved gas-concrete block is capable of performing the two principal functions of a shell structure, including the function of thermal protection and the bearing function. The functions are performed simultaneously. Therefore, the application of the above masonry material means the design development and erection of exterior walls of residential buildings noteworthy for their thermal efficiency. In the event of frameless structures, the height of the residential building in question may be up to 5 stories, while the use of a monolithic or a ready-made frame makes it possible to build high-rise buildings, and the number of stories is not limited in this case. If the average block density is equal to 400…500 kilograms per cubic meter, the designed wall thickness is to be equal to 400 mm. Its thermal resistance may be lower than the one set in the event of the per-element design of the thermal protection (Rreq = 3.41 м2 C/Watt, in Ufa, although it will meet the requirements of the applicable regulations if per-unit power consumption rate is considered.

  2. TRANSPARENT CONCRETE

    OpenAIRE

    Sandeep Sharma*, Dr. O.P. Reddy

    2017-01-01

    Transparent concrete is the new type of concrete introduced in todays world which carries special property of light transmitting due to presence of light Optical fibres. Which is also known as translucent concrete or light transmitting concrete, it is achieved by replacing coarse aggregates with transparent alternate materials (Optical fibres). The binding material in transparent concrete may be able to transmit light by using clear resins the concrete mix. The concrete used in industry in pr...

  3. Dynamic research of masonry vault in a technical scale

    Science.gov (United States)

    Golebiewski, Michal; Lubowiecka, Izabela; Kujawa, Marcin

    2017-03-01

    The paper presents preliminary results of dynamic tests of the masonry barrel vault in a technical scale. Experimental studies are intended to identify material properties of homogenized masonry vaults under dynamic loads. The aim of the work is to create numerical models to analyse vault's dynamic response to dynamic loads in a simplest and accurate way. The process of building the vault in a technical scale is presented in the paper. Furthermore a excitation of vibrations with an electrodynamic modal exciter placed on the vault, controlled by an arbitrary waveform function generator, is discussed. Finally paper presents trends in the research for homogenization algorithm enabling dynamic analysis of masonry vaults. Experimental results were compared with outcomes of so-called macromodels (macromodel of a brick masonry is a model in which masonry, i.e. a medium consisting of two different fractions - bricks and mortar, is represented by a homogenized, uniformed, material). Homogenization entail significant simplifications, nevertheless according to the authors, can be a useful approach in a static and dynamic analysis of masonry structures.

  4. Failure Criterion for Brick Masonry: A Micro-Mechanics Approach

    Science.gov (United States)

    Kawa, Marek

    2015-02-01

    The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading conditions at different orientations of bed joints. The performance of the approach is verified against solutions obtained for corresponding layered and block microstructures, which provides the upper and lower strength bounds for masonry microstructure, respectively. Subsequently, a phenomenological anisotropic strength criterion for masonry microstructure is proposed. The criterion has a form of conjunction of Jaeger critical plane condition and Tsai-Wu criterion. The model proposed is identified based on the fitting of numerical results obtained from the microstructural analysis. Identified criterion is then verified against results obtained for different loading orientations. It appears that strength of masonry microstructure can be satisfactorily described by the criterion proposed.

  5. Failure Criterion for Brick Masonry: A Micro-Mechanics Approach

    Directory of Open Access Journals (Sweden)

    Kawa Marek

    2015-02-01

    Full Text Available The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading conditions at different orientations of bed joints. The performance of the approach is verified against solutions obtained for corresponding layered and block microstructures, which provides the upper and lower strength bounds for masonry microstructure, respectively. Subsequently, a phenomenological anisotropic strength criterion for masonry microstructure is proposed. The criterion has a form of conjunction of Jaeger critical plane condition and Tsai-Wu criterion. The model proposed is identified based on the fitting of numerical results obtained from the microstructural analysis. Identified criterion is then verified against results obtained for different loading orientations. It appears that strength of masonry microstructure can be satisfactorily described by the criterion proposed.

  6. Study of the brickwork masonry cracking with a cohesive fracture model

    Directory of Open Access Journals (Sweden)

    Reyes, E.

    2011-09-01

    Full Text Available This paper presents a numerical procedure to simulate the cracking process of the brickwork masonry under tensile/shear loading. The model is an extension of the cohesive model prepared by the authors for concrete, and takes into account the anisotropy of the material. The numerical procedure includes two steps: 1 calculation of the crack path with a linear elastic fracture model, 2 after the crack path is obtained, an interface finite element (using the cohesive fracture model is incorporated into the trajectory. Such a model is then implemented into a commercial code by means of a user subroutine, consequently being contrasted with experimental results. Fracture properties of masonry are independently measured for two directions on the composed masonry, and then input in the numerical model. This numerical procedure accurately predicts the experimental mixed mode fracture records for different orientations of the brick layers on masonry panels.

    Este artículo presenta un modelo de cálculo que permite simular el comportamiento en rotura de la fábrica de ladrillo bajo solicitaciones de tracción y cortante. El modelo extiende el modelo cohesivo formulado por los autores para hormigón, considerando la anisotropía del material. El procedimiento de cálculo consta de dos fases: 1 obtención de la trayectoria de grieta mediante un cálculo elástico lineal, 2 incorporación del modelo cohesivo en la misma mediante elementos de intercara. El modelo se ha implementado en un programa de elementos finitos comercial con una subrutina de usuario y se ha contrastado con los resultados experimentales de los ensayos a escala. Las propiedades mecánicas de la fábrica, en especial las de fractura, se miden con ensayos de caracterización en dos direcciones. Éstas se incorporan al modelo de cálculo para simular los ensayos de fractura en modo mixto, prediciendo los resultados adecuadamente para distintas orientaciones de los tendeles.

  7. Materials development and field demonstration of high-recycled-content concrete for energy-efficient building construction; FINAL

    International Nuclear Information System (INIS)

    Ostowari, Ken; Nosson, Ali

    2000-01-01

    The project developed high-recycled-content concrete material with balanced structural and thermal attributes for use in energy-efficient building construction. Recycled plastics, tire, wool, steel and concrete were used as replacement for coarse aggregates in concrete and masonry production. With recycled materials the specific heat and thermal conductivity of concrete could be tailored to enhance the energy-efficiency of concrete buildings. A comprehensive field project was implemented which confirmed the benefits of high-recycled-content concrete for energy-efficient building construction

  8. Numerical modelling of failure of cement concrete using a unit cell ...

    Indian Academy of Sciences (India)

    Unit cell approach is a simple mathematical approximation that helps us to simplify the simulation of mechanical response of multi-phase composites. To model the failure of matrix, brittle cracking model is used, where the entire fracture zone is represented by a band of micro cracked material. Current study involves;. failure ...

  9. A Study of Potential Load Bearing Masonry (LBM System in Malaysia Construction Industry

    Directory of Open Access Journals (Sweden)

    Ramli N.A.

    2014-01-01

    Full Text Available To overcome the problems in increasing of material prices, land prices, shortage of skilled workers, equipping low cost housing demands and maintained the cost of the constructing at an affordable price, there is a need to find the alternative solution for constructing method. The use of the load bearing masonry system (LBM has been identified as a sustainable and an effective alternative method for the construction industry. The system offers several advantages in term of cost and speed of the construction, durability, strength, environmentally friendly practices and aesthetic qualities. Despite these advantages, unfortunately, this system has not been widely used in Malaysia compared to reinforced concrete (RC frame construction. Therefore, this paper aims to discuss the advantages and potential of the system implementation to Malaysia construction industry in the future.

  10. Experimental Evaluation of Lightweight AAC Masonry Wall Prisms with Ferrocement Layers in Compression and Flexure

    KAUST Repository

    Abdel Mooty, Mohamed

    2012-05-01

    An experimental program is designed to evaluate the performance of lightweight autoclaved aerated concrete masonry wall strengthened using ferrocement layers, in a sandwich structure, under in-plane compression and out-of-plane bending. The 25 mm thick ferrocement mortar is reinforced with steel welded wire mesh of 1 mm diameters at 15 mm spacing. Different types of shear connectors are used to evaluate their effect on failure loads. The effect of different design parameters on the wall strength are considered including wall thickness, mortar strength, and type and distribution of shear connectors. A total of 20 prisms are tested in compression and 5 prisms are tested under bending. The proposed ferrocement strengthening technique is easy to apply on existing wall system and results in significant strength and stiffness enhancement of the tested wall specimens. © (2012) Trans Tech Publications.

  11. How Concrete is Concrete

    OpenAIRE

    Koeno Gravemeijer

    2010-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two diff...

  12. CH of masonry materials via meshless meso-modeling

    Directory of Open Access Journals (Sweden)

    Giuseppe Giambanco

    2014-07-01

    Full Text Available In the present study a multi-scale computational strategy for the analysis of masonry structures is presented. The structural macroscopic behaviour is obtained making use of the Computational Homogenization (CH technique based on the solution of the boundary value problem (BVP of a detailed Unit Cell (UC chosen at the meso-scale and representative of the heterogeneous material. The smallest UC is composed by a brick and half of its surrounding joints, the former assumed to behave elastically while the latter considered with an elastoplastic softening response. The governing equations at the macroscopic level are formulated in the framework of finite element method while the Meshless Method (MM is adopted to solve the BVP at the mesoscopic level. The work focuses on the BVP solution. The consistent tangent stiffness matrix at a macroscopic quadrature point is evaluated on the base of BVP results for the UC together with a localisation procedure. Validation of the MM procedure at the meso-scale level is demonstrated by numerical examples that show the results of the BVP for the simple cases of normal and shear loading of the UC.

  13. Role of masonry infill in seismic resistant resistance of RC structures

    International Nuclear Information System (INIS)

    Taher, Salah El-Din F.; Afefy, Hamdy Mohy El-Din

    2008-01-01

    The influence of partial masonry infilling on the seismic lateral behavior of low, medium and high rise buildings is addressed. The most simple equivalent frame system with reduced degrees of freedom is proposed for handling multi-story multi-bay infilled frames. The system is composed of a homogenized continuum for the reinforced concrete members braced with unilateral diagonal struts for each bay, which are only activated in compression. Identification of the equivalent characteristics and nonlinear material properties is accomplished from the concepts of inverse analysis, along with statistical tests of the hypotheses, employed to establish the appropriate filtering scheme and the proper accuracy tolerance. The suggested system allows for nonlinear finite element static and dynamic analysis of sophisticated infilled reinforced concrete frames. Sensitivity analysis is undertaken to check the suitability of the proposed system to manipulate various structural applications. The effect of number of stories, number of bays, infill proportioning and infill locations are investigated. Geometric and material nonlinearity of both infill panel and reinforced concrete frame are considered in the nonlinear finite element analysis. Energy consideration using modified Rayleigh's method is employed to figure out the response parameters under lateral dynamic excitations. The results reflect the significance of infill in increasing the strength, stiffness and frequency of the entire system depending on the position and amount of infilling. Lower infilling is noted to provide more stiffness for the system as compared with upper locations. (author)

  14. How Concrete is Concrete

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2010-07-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics

  15. A General Discussion of Problems Related to the Determination of Concrete Armour Unit Stresses Including Specific Results related to Static and Dynamic Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1989-01-01

    Recent breakwater failures revealed the shortcomings of the traditional design procedures for concrete armour units. This paper deals with one of them, which can be expressed as the "lack of balance between the hydraulic stability of the armour layer and the mechanical strength or integrity...... of the units". This problem is related mainly to the slender types of armour units. The paper discusses the various types of loads, and the practical determination of the wave and gravity induced loads and stresses, especially the model test technique and its restrictions. Examples related to Dolosse...

  16. Measure Guideline. Deep Energy Enclosure Retrofit for Interior Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Musunuru, S. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

    2015-04-30

    This Measure Guideline describes a deep energy enclosure retrofit solution for insulating mass masonry buildings from the interior. It describes the retrofit assembly, technical details, and installation sequence for retrofitting masonry walls. Interior insulation of masonry retrofits might adversely affect the durability of the wall. This guideline includes a review of decision criteria pertinent to retrofitting masonry walls from the interior and the possible risk of freeze-thaw damage.

  17. Influence of the mechanical properties of lime mortar on the strength of brick masonry

    OpenAIRE

    PAVIA, SARA

    2013-01-01

    PUBLISHED This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar?s compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar?s st...

  18. Measure Guideline: Deep Energy Enclosure Retrofit for Interior Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Musunuru, S. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

    2015-04-01

    This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution for insulating mass masonry buildings from the interior. It describes the retrofit assembly, technical details, and installation sequence for retrofitting masonry walls. Interior insulation of masonry retrofits has the potential to adversely affect the durability of the wall; this document includes a review of decision criteria pertinent to retrofitting masonry walls from the interior and the possible risk of freeze-thaw damage.

  19. Performance of masonry structures during earthquake-2005 in kashmir

    International Nuclear Information System (INIS)

    Javed, M.

    2008-01-01

    The Kashmir earthquake of October 8th, 2005 was one of the deadliest earthquakes according to the number of fatalities in the history of indo-Pakistan subcontinent. More than 70,000 people were killed, mainly due to collapse of masonry buildings being widely used in Kashmir and Northern Pakistan. Major causes of damages/ collapse of masonry buildings were: poor quality of mortar, undressed stones, flexible roofs not bonded to supporting walls, lateral thrust from inclined roofs, unbraced parapet and gable walls, non-anchored infilled walls, wide openings without surrounding reinforcement, heavy roofs resting on poor quality masonry walls, etc. A critical review of damages to masonry structures is presented in the paper along with measures that need to be taken in future construction. In order to minimize the losses in masonry structures in case of future seismic activities, strategies such as loss assessment are discuss, a part of which has already been taken as a research project by the authors. (author)

  20. Seismic and Restoration Assessment of Monumental Masonry Structures

    Directory of Open Access Journals (Sweden)

    Panagiotis G. Asteris

    2017-08-01

    Full Text Available Masonry structures are complex systems that require detailed knowledge and information regarding their response under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake-resistant design and/or assessment. However, modelling a real structure with a robust quantitative (mathematical representation is a very difficult, complex and computationally-demanding task. The paper herein presents a new stochastic computational framework for earthquake-resistant design of masonry structural systems. The proposed framework is based on the probabilistic behavior of crucial parameters, such as material strength and seismic characteristics, and utilizes fragility analysis based on different failure criteria for the masonry material. The application of the proposed methodology is illustrated in the case of a historical and monumental masonry structure, namely the assessment of the seismic vulnerability of the Kaisariani Monastery, a byzantine church that was built in Athens, Greece, at the end of the 11th to the beginning of the 12th century. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structure, by means of comparison of the results obtained.

  1. Seismic and Restoration Assessment of Monumental Masonry Structures.

    Science.gov (United States)

    Asteris, Panagiotis G; Douvika, Maria G; Apostolopoulou, Maria; Moropoulou, Antonia

    2017-08-02

    Masonry structures are complex systems that require detailed knowledge and information regarding their response under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake-resistant design and/or assessment. However, modelling a real structure with a robust quantitative (mathematical) representation is a very difficult, complex and computationally-demanding task. The paper herein presents a new stochastic computational framework for earthquake-resistant design of masonry structural systems. The proposed framework is based on the probabilistic behavior of crucial parameters, such as material strength and seismic characteristics, and utilizes fragility analysis based on different failure criteria for the masonry material. The application of the proposed methodology is illustrated in the case of a historical and monumental masonry structure, namely the assessment of the seismic vulnerability of the Kaisariani Monastery, a byzantine church that was built in Athens, Greece, at the end of the 11th to the beginning of the 12th century. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structure, by means of comparison of the results obtained.

  2. Calibration under uncertainty for finite element models of masonry monuments

    Energy Technology Data Exchange (ETDEWEB)

    Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin

    2010-02-01

    Historical unreinforced masonry buildings often include features such as load bearing unreinforced masonry vaults and their supporting framework of piers, fill, buttresses, and walls. The masonry vaults of such buildings are among the most vulnerable structural components and certainly among the most challenging to analyze. The versatility of finite element (FE) analyses in incorporating various constitutive laws, as well as practically all geometric configurations, has resulted in the widespread use of the FE method for the analysis of complex unreinforced masonry structures over the last three decades. However, an FE model is only as accurate as its input parameters, and there are two fundamental challenges while defining FE model input parameters: (1) material properties and (2) support conditions. The difficulties in defining these two aspects of the FE model arise from the lack of knowledge in the common engineering understanding of masonry behavior. As a result, engineers are unable to define these FE model input parameters with certainty, and, inevitably, uncertainties are introduced to the FE model.

  3. Understanding the tensile behaviour of masonry parallel to the bed joints: A numerical approach

    NARCIS (Netherlands)

    Lourenço, P.B.; Rots, J.G.; Pluijm, R. van der

    1999-01-01

    The lack of experimental data for the complete characterisation of the inelastic behaviour of masonry is a key issue in numerical modelling of masonry structures. A solution to obtain the material properties of masonry at the macro-level is to derive them on the basis of the geometrical and material

  4. Partnering with a local concrete block manufacturing plant to improve quality of construction materials in Haiti’s Central Plateau

    Directory of Open Access Journals (Sweden)

    Aaron Gordon

    2016-09-01

    Full Text Available This paper presents a successful ongoing partnership between Clemson Engineers for Developing Countries (CEDC and a concrete masonry unit (CMU manufacturing plant in rural Haiti. The infrastructure destruction and resulting loss of life of the 2010 earthquake in Haiti highlighted the need for improved building materials and codes. This partnership has helped to improve the strength of CMUs in the plant, both creating a safer local built environment and expanding the economic opportunities for this plant. Using samples of aggregate and cement from the site in Haiti, students in Clemson performed experiments to optimise the CMU mix design and made other suggestions to improve efficiency and quality of their product. Consistency continues to be a challenge for the CMU plant, and this paper also describes proposed procedures to help the plant implement quality control and quality assurance plans.

  5. Corrosion and chemical resistant masonry materials handbook

    National Research Council Canada - National Science Library

    Sheppard, Walter Lee

    1986-01-01

    ... and other equipment. But few other than chemists and chemical engineers identify "corrosion" as chemical degradation or destruction of a material, and therefore, something that can happen to nonmetals (concrete, plastics, brick, timber, etc.) as well as to nletals. The National Association of Corrosion Engineers so defined "corrosion" over thirty years ago but this f...

  6. Influence of Additives on Masonry and Protective Paints’ Quality

    Science.gov (United States)

    Kostiunina, I. L.; Vyboishchik, A. V.

    2017-11-01

    The environment is one of main factors influencing the living conditions of urban population in Russia nowadays. One of the main drawbacks restraining the aesthetic improvement process of modern Russian cities is unsatisfactory protection of buildings from atmospheric phenomena. Moreover, industrial waste in modern industrial cities of Russia prevents a long-lasting decoration of urban buildings. The article presents an overview of the composition and physical properties of masonry paints applied in the Chelyabinsk region. The traditional technology of coatings obtaining is studied, the drawbacks of this technology are examined, the new materials and applications are offered. The influence of additives on the basic properties of masonry paints, viz. weather resistance, viscosity, hardness, cost, is considered. The application of new technologies utilizing industrial waste can solve the abovestated problem, which also, along with improving basic physical and chemical properties, will result in the cost reduction and the increase of the masonry paints hardness.

  7. Linear Shrinkage Behaviour of Compacted Loam Masonry Blocks

    Directory of Open Access Journals (Sweden)

    NAWAB ALI LAKHO

    2017-04-01

    Full Text Available Walls of wet loam, used in earthen houses, generally experience more shrinkage which results in cracks and less compressive strength. This paper presents a technique of producing loam masonry blocks that are compacted in drained state during casting process in order to minimize shrinkage. For this purpose, loam masonry blocks were cast and compacted at a pressure of 6 MPa and then dried in shade by covering them in plastic sheet. The results show that linear shrinkage of 2% occurred which is smaller when compared to un-compacted wet loam walls. This implies that the loam masonry blocks compacted in drained state is expected to perform better than un-compacted wet loam walls.

  8. Design of Space Truss Based Insulating Walls for Robotic Fabrication in Concrete

    OpenAIRE

    DUBALLET, Romain; Baverel, Olivier; Dirrenberger, Justin

    2017-01-01

    International audience; This work focuses on the design of ultra-light concrete walls for individual or collective housing, the normative context being constrained masonry. It is stated that current block work building is very inefficient in terms of quantity of concrete used for cinderblocks and mortar joints, and with regards to thermal insulation. Here is proposed a robotic manufacturing technique based on mortar extrusion that allows producing more efficient walls. First we present the fa...

  9. Solidification of low-level radioactive wastes in masonry cement

    International Nuclear Information System (INIS)

    Zhou, H.; Colombo, P.

    1987-03-01

    Portland cements are widely used as solidification agents for low-level radioactive wastes. However, it is known that boric acid wastes, as generated at pressurized water reactors (PWR's) are difficult to solidify using ordinary portland cements. Waste containing as little as 5 wt % boric acid inhibits the curing of the cement. For this purpose, the suitability of masonry cement was investigated. Masonry cement, in the US consists of 50 wt % slaked lime (CaOH 2 ) and 50 wt % of portland type I cement. Addition of boric acid in molar concentrations equal to or less than the molar concentration of the alkali in the cement eliminates any inhibiting effects. Accordingly, 15 wt % boric acid can be satisfactorily incorporated into masonry cement. The suitability of masonry cement for the solidification of sodium sulfate wastes produced at boiling water reactors (BWR's) was also investigated. It was observed that although sodium sulfate - masonry cement waste forms containing as much as 40 wt % Na 2 SO 4 can be prepared, waste forms with more than 7 wt % sodium sulfate undergo catastrophic failure when exposed to an aqueous environment. It was determined by x-ray diffraction that in the presence of water, the sulfate reacts with hydrated calcium aluminate to form calcium aluminum sulfate hydrate (ettringite). This reaction involves a volume increase resulting in failure of the waste form. Formulation data were identified to maximize volumetric efficiency for the solidification of boric acid and sodium sulfate wastes. Measurement of some of the waste form properties relevant to evaluating the potential for the release of radionuclides to the environment included leachability, compression strengths and chemical interactions between the waste components and masonry cement. 15 refs., 19 figs., 9 tabs

  10. Horizontal impact testing of quarter scale flasks using masonry targets

    International Nuclear Information System (INIS)

    Tufton, E.P.S.

    1985-01-01

    The programme leading up to the Train Crash Demonstration included investigation of flask impacts, in horizontal motion, against masonry targets representing abutment structures. An outline is given of a series of eight tests, of which five are described in detail. All the tests used quarter-scale flasks, and the design and construction of the appropriate brick and stone masonry targets is described. A summary of results is given in terms of damage to the model flask compared with the more severe damage seen in regulatory drop tests. (author)

  11. How Concrete is Concrete?

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2011-01-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics.Key words:  Conceret Learning Materials, School Math, Common Sense, Scaffolding, Communication DOI: http://dx.doi.org/10.22342/jme.2.1.780.1-14

  12. Retrofit of a MultiFamily Mass Masonry Building in New England

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Kerrigan, P. [Building Science Corporation, Somerville, MA (United States); Wytrykowska, H. [Building Science Corporation, Somerville, MA (United States); Van Straaten, R. [Building Science Corporation, Somerville, MA (United States)

    2013-08-01

    Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The research performed for this project provides information regarding advanced retrofit packages for multi-family masonry buildings in Cold climates. In particular, this project demonstrates safe, durable, and cost-effective solutions that will potentially benefit millions of multi-family brick buildings throughout the East Coast and Midwest (Cold climates). The retrofit packages provide insight on the opportunities for and constraints on retrofitting multifamily buildings with ambitious energy performance goals but a limited budget. The condominium conversion project will contribute to several areas of research on enclosures, space conditioning, and water heating. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection, and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.

  13. Investigation of Hydraulic Binding Characteristics of Lime Based Mortars Used in Historical Masonry Structures

    Science.gov (United States)

    Binal, Adil

    2017-10-01

    In the historic masonry structures, hard and large rock fragments were used as the construction materials. The hydraulic binder material prepared to keep this used material in its entirety is a different material than the cement used today. Khorasan mortar made by using aggregate and lime exhibits a more flexible structure than the concrete. This feature allows the historic building to be more durable. There is also a significant industrial value because of the use of Khorasan mortar in the restoration of historic masonry structures. Therefore, the calculation of the ideal mixture of Khorasan mortar and the determination of its mechanical and physical properties are of great importance regarding preserving historic buildings. In this study, the mixtures of different lime and brick fractions were prepared. It was determined that Khorasan mortar shows the highest compressive strength in mixtures with water/lime ratio of 0.55 and lime/aggregate ratio of 0.66. By keeping the mixing ratio constant, it was observed that the strengths of the samples kept in the humidity chamber for different curing times increased day by day. The early strength values of samples with the high lime/aggregate ratio (l/a: 0.83) were higher than those with the low lime/aggregate ratio (l/a: 0.5). For the samples with low lime/aggregate ratio, there was an increase in the strength values depending on the curing period. As the cure duration increases, a chemical reaction takes place between the lime and the brick fracture, and as a result of this reaction, the strength values are increased.

  14. Image-Based Delineation and Classification of Built Heritage Masonry

    Directory of Open Access Journals (Sweden)

    Noelia Oses

    2014-02-01

    Full Text Available Fundación Zain is developing new built heritage assessment protocols. The goal is to objectivize and standardize the analysis and decision process that leads to determining the degree of protection of built heritage in the Basque Country. The ultimate step in this objectivization and standardization effort will be the development of an information and communication technology (ICT tool for the assessment of built heritage. This paper presents the ground work carried out to make this tool possible: the automatic, image-based delineation of stone masonry. This is a necessary first step in the development of the tool, as the built heritage that will be assessed consists of stone masonry construction, and many of the features analyzed can be characterized according to the geometry and arrangement of the stones. Much of the assessment is carried out through visual inspection. Thus, this process will be automated by applying image processing on digital images of the elements under inspection. The principal contribution of this paper is the automatic delineation the framework proposed. The other contribution is the performance evaluation of this delineation as the input to a classifier for a geometrically characterized feature of a built heritage object. The element chosen to perform this evaluation is the stone arrangement of masonry walls. The validity of the proposed framework is assessed on real images of masonry walls.

  15. Study on vulnerability matrices of masonry buildings of mainland China

    Science.gov (United States)

    Sun, Baitao; Zhang, Guixin

    2018-04-01

    The degree and distribution of damage to buildings subjected to earthquakes is a concern of the Chinese Government and the public. Seismic damage data indicates that seismic capacities of different types of building structures in various regions throughout mainland China are different. Furthermore, the seismic capacities of the same type of structure in different regions may vary. The contributions of this research are summarized as follows: 1) Vulnerability matrices and earthquake damage matrices of masonry structures in mainland China were chosen as research samples. The aim was to analyze the differences in seismic capacities of sample matrices and to present general rules for categorizing seismic resistance. 2) Curves relating the percentage of damaged masonry structures with different seismic resistances subjected to seismic demand in different regions of seismic intensity (VI to X) have been developed. 3) A method has been proposed to build vulnerability matrices of masonry structures. The damage ratio for masonry structures under high-intensity events such as the Ms 6.1 Panzhihua earthquake in Sichuan province on 30 August 2008, was calculated to verify the applicability of this method. This research offers a significant theoretical basis for predicting seismic damage and direct loss assessment of groups of buildings, as well as for earthquake disaster insurance.

  16. Integration of parametric measures and the statics of masonry panels

    Czech Academy of Sciences Publication Activity Database

    Lucchesi, M.; Šilhavý, Miroslav; Zani, N.

    2011-01-01

    Roč. 2, č. 1 (2011), s. 33-44 ISSN 1867-6936 Institutional research plan: CEZ:AV0Z10190503 Keywords : masonry panels * limit analysis * integration of measures Subject RIV: BA - General Mathematics http://www.springerlink.com/content/e0086750m731182u/

  17. Development of a national code of practice for structural masonry ...

    African Journals Online (AJOL)

    The problems and constraints faced by most developing countries, particularly Ghana, in developing codes of practice for structural masonry are highlighted. The steps that must be undertaken through the coordinated efforts of the National Standards Boards, Research Institutions, Universities and Professional Bodies in the ...

  18. Confusing cracks and difficult deformations : Interpreting structural damage in masonry

    NARCIS (Netherlands)

    De Vent, I.; Rots, J.G.; Van Hees, R.P.J.; Hobbelman, G.J.

    2012-01-01

    Cracks and deformatiçns in masonry are common phenomena in historical buildings. If they are interpreted correctly, they can be an extremely valuable source çf informatiçn on the load history of the premises. Nevertheless, this interpretation is not always as obvious as one may think. In the

  19. Structural damage in masonry : Developing diagnostic decision support

    NARCIS (Netherlands)

    De Vent, I.A.E.

    2011-01-01

    This thesis deals with the diagnosis of structural damage in traditional masonry: cracks, deformations and tilts. Establishing the cause of this type of damage can be difficult. This research project has aimed to improve and facilitate the diagnostic process by offering support in the initial phase

  20. New Frontiers on Seismic Modeling of Masonry Structures

    Directory of Open Access Journals (Sweden)

    Salvatore Caddemi

    2017-07-01

    Full Text Available An accurate evaluation of the non-linear behavior of masonry structural elements in existing buildings still represents a complex issue that rigorously requires non-linear finite element strategies difficult to apply to real large structures. Nevertheless, for the static and seismic assessment of existing structures, involving the contribution of masonry materials, engineers need reliable and efficient numerical tools, whose complexity and computational demand should be suitable for practical purposes. For these reasons, the formulation and the validation of simplified numerical strategies represent a very important issue in masonry computational research. In this paper, an innovative macroelement approach, developed by the authors in the last decade, is presented. The proposed macroelement formulation is based on different, plane and spatial, macroelements for the simulation of both the in-plane and out-of-plane behavior of masonry structures also in presence of masonry elements with curved geometry. The mechanical response of the adopted macroelement is governed by non-linear zero-thickness interfaces, whose calibration follows a straightforward fiber discretization, and the non-linear internal shear deformability is ruled by equivalence with a corresponding geometrically consistent homogenized medium. The approach can be considered as “parsimonious” since the kinematics of the adopted elements is controlled by very few degrees of freedom, if compared to a corresponding discretization performed by using non-linear finite element method strategies. This innovative discrete element strategy has been implemented in two user-oriented software codes 3DMacro (Caliò et al., 2012b and HiStrA (Historical Structures Analysis (Caliò et al., 2015, which simplify the modeling of buildings and historical structures by means of several wizard generation tools and input/output facilities. The proposed approach, that represents a powerful tool for the

  1. Probabilistic seismic vulnerability and risk assessment of stone masonry structures

    Science.gov (United States)

    Abo El Ezz, Ahmad

    Earthquakes represent major natural hazards that regularly impact the built environment in seismic prone areas worldwide and cause considerable social and economic losses. The high losses incurred following the past destructive earthquakes promoted the need for assessment of the seismic vulnerability and risk of the existing buildings. Many historic buildings in the old urban centers in Eastern Canada such as Old Quebec City are built of stone masonry and represent un-measurable architectural and cultural heritage. These buildings were built to resist gravity loads only and generally offer poor resistance to lateral seismic loads. Seismic vulnerability assessment of stone masonry buildings is therefore the first necessary step in developing seismic retrofitting and pre-disaster mitigation plans. The objective of this study is to develop a set of probability-based analytical tools for efficient seismic vulnerability and uncertainty analysis of stone masonry buildings. A simplified probabilistic analytical methodology for vulnerability modelling of stone masonry building with systematic treatment of uncertainties throughout the modelling process is developed in the first part of this study. Building capacity curves are developed using a simplified mechanical model. A displacement based procedure is used to develop damage state fragility functions in terms of spectral displacement response based on drift thresholds of stone masonry walls. A simplified probabilistic seismic demand analysis is proposed to capture the combined uncertainty in capacity and demand on fragility functions. In the second part, a robust analytical procedure for the development of seismic hazard compatible fragility and vulnerability functions is proposed. The results are given by sets of seismic hazard compatible vulnerability functions in terms of structure-independent intensity measure (e.g. spectral acceleration) that can be used for seismic risk analysis. The procedure is very efficient for

  2. Effect of horizontal reinforcement in strengthening of masonry members

    International Nuclear Information System (INIS)

    Farooq, S.H.; Ilyas, M.; Ggaffar, A.

    2008-01-01

    An experimental research program was undertaken to ascertain the effectiveness of a new technique for strengthening masonry wall panels using steel strips on compressive and shear strength enhancement. The experimental work includes eight wall panels, four each for compressive and shear strength evaluation. This work was the phase I of extensive research project which include testing of strengthened masonry wall panels under monotonic load (Phase-I), static cyclic load (Phase-2) and dynamic load (Phase-3). The wall panels were strengthened with different steel strip arrangements, which consist of single/double face application of coarse and fine steel strip mesh with reduced spacing of horizontal strips. This paper investigates only the effectiveness of horizontal steel strips on strength enhancement. Four masonry wall panels are considered in two groups and in each group, one wall was retrofitted with coarse steel mesh on single face and on second wall fine steel mesh was applied on one side. Furthermore, test results of strengthened specimens are also compared with the un-strengthened specimen (REFE). The mechanisms by which load was carried were observed, varying from the initial, uncracked state, and the final, fully cracked state. The results demonstrate a quite significant increase in the compressive and shear capacity of strengthened panels as compared to REFE-panel. However, increase in the compressive strength of fine mesh above that of coarse mesh is negligible. The technique/approach is found quite viable for strengthening of masonry walls, for rehabilitation of old deteriorated buildings and unreinforced masonry structures in seismic zones. (author)

  3. Seismic vulnerability of the Himalayan half-dressed rubble stone masonry structures, experimental and analytical studies

    Directory of Open Access Journals (Sweden)

    N. Ahmad

    2012-11-01

    Full Text Available Half-Dressed rubble stone (DS masonry structures as found in the Himalayan region are investigated using experimental and analytical studies. The experimental study included a shake table test on a one-third scaled structural model, a representative of DS masonry structure employed for public critical facilities, e.g. school buildings, offices, health care units, etc. The aim of the experimental study was to understand the damage mechanism of the model, develop damage scale towards deformation-based assessment and retrieve the lateral force-deformation response of the model besides its elastic dynamic properties, i.e. fundamental vibration period and elastic damping. The analytical study included fragility analysis of building prototypes using a fully probabilistic nonlinear dynamic method. The prototypes are designed as SDOF systems assigned with lateral, force-deformation constitutive law (obtained experimentally. Uncertainties in the constitutive law, i.e. lateral stiffness, strength and deformation limits, are considered through random Monte Carlo simulation. Fifty prototype buildings are analyzed using a suite of ten natural accelerograms and an incremental dynamic analysis technique. Fragility and vulnerability functions are derived for the damageability assessment of structures, economic loss and casualty estimation during an earthquake given the ground shaking intensity, essential within the context of risk assessment of existing stock aiming towards risk mitigation and disaster risk reduction.

  4. Experimental Estimation Of Energy Damping During Free Rocking Of Unreinforced Masonry Walls. First Results

    International Nuclear Information System (INIS)

    Sorrentino, Luigi; Masiani, Renato; Benedetti, Stefano

    2008-01-01

    This paper presents an ongoing experimental program on unreinforced masonry walls undergoing free rocking. Aim of the laboratory campaign is the estimation of kinetic energy damping exhibited by walls released with non-zero initial conditions of motion. Such energy damping is necessary for dynamic modelling of unreinforced masonry local mechanisms. After a brief review of the literature on this topic, the main features of the laboratory tests are presented. The program involves the experimental investigation of several parameters: 1) unit material (brick or tuff), 2) wall aspect ratio (ranging between 14.5 and 7.1), 3) restraint condition (two-sided or one-sided rocking), and 4) depth of the contact surface between facade and transverse walls (one-sided rocking only). All walls are single wythe and the mortar is pozzuolanic. The campaign is still in progress. However, it is possible to present the results on most of the mechanical properties of mortar and bricks. Moreover, a few time histories are reported, already indicating the need to correct some of the assumptions frequent in the literature

  5. Structural Precast Concrete Handbook

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly.......Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly....

  6. Investigation on Wall Panel Sandwiched With Lightweight Concrete

    Science.gov (United States)

    Lakshmikandhan, K. N.; Harshavardhan, B. S.; Prabakar, J.; Saibabu, S.

    2017-08-01

    The rapid population growth and urbanization have made a massive demand for the shelter and construction materials. Masonry walls are the major component in the housing sector and it has brittle characteristics and exhibit poor performance against the uncertain loads. Further, the structure requires heavier sections for carrying the dead weight of masonry walls. The present investigations are carried out to develop a simple, lightweight and cost effective technology for replacing the existing wall systems. The lightweight concrete is developed for the construction of sandwich wall panel. The EPS (Expanded Polystyrene) beads of 3 mm diameter size are mixed with concrete and developed a lightweight concrete with a density 9 kN/m3. The lightweight sandwich panel is cast with a lightweight concrete inner core and ferrocement outer skins. This lightweight wall panel is tested for in-plane compression loading. A nonlinear finite element analysis with damaged plasticity model is carried out with both material and geometrical nonlinearities. The experimental and analytical results were compared. The finite element study predicted the ultimate load carrying capacity of the sandwich panel with reasonable accuracy. The present study showed that the lightweight concrete is well suitable for the lightweight sandwich wall panels.

  7. Glazed Concrete

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    Why glazed concrete? Concrete hardens and finds its strength at room temperature whereas clay products must first be fired before they achieve this strength. They are stronger and three times as durable as clay products, which is a weighty reason for choosing concrete.5 Another reason, which....... If this succeeds, it will be possible to manufacture thin, large-scale glazed concrete panels comparable in size to concrete sandwich construction and larger which, with or without back-casting, can work as load-bearing construction elements....

  8. Concrete performance using low-degradation aggregates.

    Science.gov (United States)

    2012-06-01

    The durability of Portland cement concrete (PCC) has long been identified as a concern by transportation communities around the United States. In this study, the long-term performance of two batches of concrete incorporating either low-degradation (L...

  9. Evaluation of Two CEDA Weatherization Pilot Implementations of an Exterior Insulation and Over-Clad Retrofit Strategy for Residential Masonry Buildings in Chicago

    Energy Technology Data Exchange (ETDEWEB)

    Neuhauser, K.

    2013-08-01

    This project examines the implementation of an exterior insulation and over-clad strategy for brick masonry buildings in Chicago. The strategy was implemented at a free-standing two story two-family dwelling and a larger free-standing multifamily building. The test homes selected for this research represent predominant housing types for the Chicago area. High heating energy use typical in these buildings threaten housing affordability. Uninsulated mass masonry wall assemblies also have a strongly detrimental impact on comfort. Significant changes to the performance of masonry wall assemblies is generally beyond the reach of typical weatherization (Wx) program resources. The Community and Economic Development Association of Cook County, Inc. (CEDA) has secured a Sustainable Energy Resources for Consumers (SERC) innovation grant sponsored by the United States Department of Energy (DOE). This grant provides CEDA the opportunity to pursue a pilot implementation of innovative approaches to retrofit in masonry wall enclosures. The exterior insulation and over-clad strategy implemented through this project was designed to allow implementation by contractors active in CEDA weatherization programs and using materials and methods familiar to these contractors. The retrofit measures are evaluated in terms of feasibility, cost and performance. Through observations of the strategies implemented, the research described in this report identifies measures critical to performance as well as conditions for wider adoption. The research also identifies common factors that must be considered in determining whether the exterior insulation and over-clad strategy is appropriate for the building.

  10. Concrete Hinges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2014-01-01

    In the first part of the 20th century concrete hinges developed by Freyssinet and Mesnager were widely tested and implemented in concrete structures. The concrete hinges were used a great deal in closed-spandrel arch bridges. Since such a bridge type has not been competitive for the past 40 years......, the research in concrete hinges has not evolved significantly in that period. But introducing a new state-of-the-art concrete arch bridge solution (Pearl-Chain arches invented at the Technical University of Denmark) creates a necessity of a concrete hinge research based on modern standards. Back when research....... The present paper uses the prior research results to optimize a test-setup for concrete hinge testing by means of a universal method taking into account the application of the hinge in an arch structure. 3D CAD is utilized in all steps of the planning to reduce errors during assembly of the parts in the test...

  11. Concrete structures

    CERN Document Server

    Setareh, Mehdi

    2017-01-01

    This revised, fully updated second edition covers the analysis, design, and construction of reinforced concrete structures from a real-world perspective. It examines different reinforced concrete elements such as slabs, beams, columns, foundations, basement and retaining walls and pre-stressed concrete incorporating the most up-to-date edition of the American Concrete Institute Code (ACI 318-14) requirements for the design of concrete structures. It includes a chapter on metric system in reinforced concrete design and construction. A new chapter on the design of formworks has been added which is of great value to students in the construction engineering programs along with practicing engineers and architects. This second edition also includes a new appendix with color images illustrating various concrete construction practices, and well-designed buildings. The ACI 318-14 constitutes the most extensive reorganization of the code in the past 40 years. References to the various sections of the ACI 318-14 are pro...

  12. Structural Behaviors of Reinforced Concrete Piers Rehabilitated with FRP Wraps

    Directory of Open Access Journals (Sweden)

    Junsuk Kang

    2017-01-01

    Full Text Available The use of fiber-reinforced polymer (FRP wraps to retrofit and strengthen existing structures such as reinforced concrete piers is becoming popular due to the higher tensile strength, durability, and flexibility gained and the method’s ease of handling and low installation and maintenance costs. As yet, however, few guidelines have been developed for determining the optimum thicknesses of the FRP wraps applied to external surfaces of concrete or masonry structures. In this study, nonlinear pushover finite element analyses were utilized to analyze the complex structural behaviors of FRP-wrapped reinforced rectangular piers. Design parameters such as pier section sizes, pier heights, pier cap lengths, compressive strengths of concrete, and the thicknesses of the FRP wraps used were thoroughly tested under incremental lateral and vertical loads. The results provide useful guidelines for analyzing and designing appropriate FRP wraps for existing concrete piers.

  13. Nonlinear pushover analysis of infilled concrete frames

    Science.gov (United States)

    Huang, Chao Hsun; Tuan, Yungting Alex; Hsu, Ruo Yun

    2006-12-01

    Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provided by rectangular hoops that did not meet current ACI specifications for ductile frames. For comparison purposes, the columns in three of these frames were jacketed by carbon-fiber-reinforced-polymer (CFRP) sheets to avoid possible shear failure. A nonlinear pushover analysis, in which the force-deformation relationships of individual elements were developed based on ACI 318, FEMA 356, and Chen’s model, was carried out for these frames and compared to test results. Both the failure mechanisms and impact of infills on the behaviors of these frames were examined in the study. Conclusions from the present analysis provide structural engineers with valuable information for evaluation and design of infilled concrete frame building structures.

  14. THE EVOLUTION OF THE DESIGN AND CONSTRUCTION OF MASONRY BUILDINGS IN BRAZIL

    Directory of Open Access Journals (Sweden)

    Márcio R. S. Corrêa

    2012-12-01

    Full Text Available This paper presents an overview of the use of masonry in Brazil. Some historical remarks are presented showing how masonry was introduced and has been developed in the country. A brief on the Brazilian Universities is also reviewed, showing the extensive efforts made to improve the educational system and to insert Brazil into the international masonry research environment. Current materials are shown, focusing on the use of structural and non-structural masonry. The paper points out the development of Codes, considering the most important regulated characteristics of masonry in order to be used in Brazilian constructions. The building situation is addressed, stressing the large housing demands and how the masonry industry can help to partly solve the problem. Finally, present and future challenges are discussed, showing Brazil’s constructions needs, as an emerging country.

  15. Materials Considerations Regarding Rain Penetration in Historic Fired Clay Brick Masonry

    Directory of Open Access Journals (Sweden)

    Caspar Groot

    2008-01-01

    Full Text Available Moisture is a major source of damage in historic massive masonry. Therefore control of moisture movement in masonry is instrumental to the durability of masonry buildings. From research and practical experience it is known that a series of causes may play a role regarding permeability problems in masonry. This paper is focused on materials aspects regarding water penetration in historic fired clay masonry walls, constructed with moderate-to-high absorption bricks and lime mortars; the occurrence and influence of parameters such as brick porosity, interface leakage and mortar joint resistance are discussed. Subsequently, quantitative tests results are given on the effects of these parameters on the leakage of massive walls of different thicknesses. The results of the investigations lead to a number of recommendations to be used in case of repair of historic massive masonry. Finally, attention is paid to the influence of workmanship on the permeability behaviour of historic massive walls.

  16. A thermoanalytical, X-ray diffraction and petrographic approach to the forensic assessment of fire affected concrete in the United Arab Emirates.

    Science.gov (United States)

    Alqassim, M A; Jones, M R; Berlouis, L E A; Nic Daeid, N

    2016-07-01

    For most fires, forensic investigation takes place well after building materials have cooled and knowledge of the structural damage due to heat exposure can reveal the temperature reached during an incident. Recently, there have been significant changes in the types and hence characteristics of cementitious materials used in the United Arab Emirates. Few studies focus on the application of thermo-analytical, X-ray diffraction and petrographic techniques on newly developed structures and this work aims to address this deficiency by utilising a series of parametric laboratory-based tests to assess the effects of heat on hardened concrete. Specimens were made with a design mix typically used for low-rise residential homes and storage facilities. The key constituents were: Portland cement (PC), crushed gabbro stone and dune sand with water/cement ratios of 0.4-0.5. Portland cement substitutes included ground granulated blast-furnace slag (GGBS), and silica fume (SF) at replacement percentages of up to 50% and 4%, respectively. The concrete cubes of 100-mm size were produced and standard cured to 28 days and then exposed to heat inside an electric furnace with pre-determined temperature regimes of 150°C, 300°C, 600°C and 900°C. Petrographic examination was utilised to compare the discolouration of the cooled concrete. Data derived from thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are reported in order to assess the usefulness of these techniques in fire scene investigation to differentiate between these temperature regimes. The results from the TGA indicate that the majority of the percentage weight loss for all the mixtures occurred in the range 650-700°C, which corresponds to the decarbonation of calcium carbonate, mainly from the aggregates. The endothermic DSC peak at 70-120°C relates to the loss of evaporable water. Since both of these reactions are irreversible, this information can help fire investigators estimate the

  17. Aspects of alteration of masonry historical buildings without ring beam of floor slabs

    OpenAIRE

    Ryszard Chmielewski; Leopold Kruszka; Janusz Lalka

    2016-01-01

    Some problems of alteration for building structures of a conventional masonry for which working lifetime is approaching or has exceeded the expected design life are presented. In the course of these works, non-bearing masonry walls are often removed and as a result significant damages to supporting structures are often made, and in extreme cases even building collapses. Building surveyors who prepare a structural appraisal for technical reports of damaged masonry structures, as a solution to ...

  18. A geometry-based anisotropic gradient-enhanced damage model for modelling masonry failure

    OpenAIRE

    Vandoren, Bram; Simone, A.; Sluys, L. J.

    2015-01-01

    While masonry is known for its simple method of construction, its computational analysis poses many challenges. Since masonry consists of two distinct materials, i.e. mortar joints and clay bricks, the use of a suitable and efficient numerical model is essential in order to accurately model the orthotropic structural behaviour. Moreover, due to the quasi-brittle nature of both constituents, a numerical masonry model should incorporate a robust and objective description of strain localisation ...

  19. Hygrothermal analysis of surface layers of historical masonry

    Science.gov (United States)

    Kočí, Václav; Maděra, Jiří; Keppert, Martin; Černý, Robert

    2017-11-01

    The paper deals with the hygrothermal analysis of surface layers of historical masonry. Solid brick provided with a traditional and two modified lime-based plasters is studied. The heat and moisture transport in the envelope is induced by an exposure of the wall from the exterior side to dynamic climatic conditions of Olomouc, Czech Republic. The transport processes are described using diffusion type of mathematical model based on experimentally determined material properties. The computational results indicate that hygric transport and accumulation properties of exterior plasters affect the hygrothermal performance of the underlying solid brick in a very significant way, being able to regulate the amount of transported moisture. The modified lime plasters are not found generally superior to the traditional lime plasters in that respect. Therefore, their suitability for historical masonry should be assessed case by case, with a particular attention to the climatic conditions and to the properties of the load bearing structure.

  20. Behaviour of Masonry Walls under Horizontal Shear in Mining Areas

    Science.gov (United States)

    Kadela, Marta; Bartoszek, Marek; Fedorowicz, Jan

    2017-12-01

    The paper discusses behaviour of masonry walls constructed with small-sized elements under the effects of mining activity. It presents some mechanisms of damage occurring in such structures, its forms in real life and the behaviour of large fragments of masonry walls subjected to specific loads in FEM computational models. It offers a constitutive material model, which enables numerical analyses and monitoring of the behaviour of numerical models as regards elastic-plastic performance of the material, with consideration of its degradation. Results from the numerical analyses are discussed for isolated fragments of the wall subjected to horizontal shear, with consideration of degradation, impact of imposed vertical load as well as the effect of weakening of the wall, which was achieved by introducing openings in it, on the performance and deformation of the wall.

  1. 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.

  2. 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)

  3. Seismic Assessment and Retrofit of Historical Masonry Structures

    OpenAIRE

    Cuzzilla, Roberto

    2009-01-01

    The Italian building heritage is composed mainly of masonry structures, which over the years have acquired historic significance and artistic values in the national culture. These buildings are particularly vulnerable to the seismic actions, because they were design for gravitational loads without considering seismic actions applied on them. Thus, the constructive details are not compliant with the present design code provisions (e.g. in plan or elevation structural regularity) and to avoid c...

  4. Investigation of interior post-insulated masonry walls with wooden beam ends

    DEFF Research Database (Denmark)

    Morelli, Martin; Svendsen, Svend

    2013-01-01

    The preponderant number of multistorey buildings constructed in Denmark in the period between 1850 and 1930 were built with masonry walls incorporating wooden floor beams. Given the nature of this construction, it is supposed that significant energy savings could be achieved by simply insulating...... of the wall, and this in turn may lead to increased freeze–thaw damages and moisture problems at the beam ends embedded in the masonry, when the masonry facade is subjected to driving rain. This article presents a method to investigate retrofit measures of interior-insulated masonry walls having wooden floor...... reduce the heat loss of the original wall structure by half....

  5. Concrete and criticality

    International Nuclear Information System (INIS)

    Carter, R.D.

    1978-01-01

    Concrete is a widely used structural material which occurs frequently in systems requiring criticality analyses. Ordinarily, we give little thought to what its actual composition is (as compared to reference compositions), yet in criticality safety, differences in composition can cause large changes in k-effective and it may not be easy to predict in which direction the change will occur. Concrete composition is quite variable with differences in the aggregate used in the concrete in various parts of the country providing relative large differences in k-effective. The water content of concrete can also strongly affect the reactivity of a system in which it acts as a reflector or is interspersed between fissile units. Because concrete is so common and is often (but not always) a better reflector than water, one must know the concrete compositions or be prepared to use a ''worst case'' composition. It may be a problem, however, to determine just what is the worst case. At the Hanford Plant, the aggregate normally used is basalt, which gives a composition very low in carbon as opposed to those areas (e.g., Oak Ridge) where the use of limestone aggregate will result in concrete with a high carbon content. The data presented show some of the effects found in situations using ''Hanford'' concrete, but similar effects might be found with other compositions. In some cases, the use of concrete may be incidental to the effects shown. While the numbers shown are those for actual systems, the primary intent is to alert the reader that these effects can occur. In applying this information, the analyst should use material specific to the systems being analyzed

  6. Glass Masonry - Experimental Verification of Bed Joint under Shear

    Science.gov (United States)

    Fíla, J.; Eliášová, M.; Sokol, Z.

    2017-10-01

    Glass is considered as a traditional material for building industry but was mostly used for glazing of the windows. At present, glass is an integral part of contemporary architecture where glass structural elements such as beams, stairs, railing ribs or columns became popular in the last two decades. However, using glass as structural material started at the beginning of 20th century, when masonry from hollow glass blocks were used. Using solid glass brick is very rare and only a few structures with solid glass bricks walls have been built in the last years. Pillars and walls made from solid glass bricks are mainly loaded by compression and/or bending from the eccentricity of vertical load or wind load. Due to high compressive strength of glass, the limiting factor of the glass masonry is the joint between the glass bricks as the smooth surface requires another type of mortar / glue compared to traditional masonry. Shear resistance and failure modes of brick bed joint was determined during series of tests using various mortars, two types of surface treatment and different thickness of the mortar joint. Shear tests were completed by small scale tests for mortar - determination of flexural and compressive strength of hardened mortar.

  7. Young modulus variation of a brickwork masonry element submitted to high temperatures

    Directory of Open Access Journals (Sweden)

    Maciá, M. E.

    2013-03-01

    Full Text Available In order to understand the thermal behavior of the masonry elements submitted to high temperatures we need to know the variation of their thermal properties with regard to the temperature. Submitted to high temperatures clay brick masonry presents thermomechanical effects (as the variation of Young's modulus, the thermal expansion of the unit and the mortar, spalling, losses of resistance … as well as variation of the properties of the material as result of its degradation. In this article the variation of the module of elasticity of the unit and the mortar is described with regard to high temperatures according to the state of the knowledge. In this article is also exposed the results obtained from the experimental program carried out on elements of clay brick masonry submitted to high temperatures in order to observe the variation of Young's module related to temperature.

    La definición del comportamiento térmico de los elementos de fábrica sometidos a la acción del fuego requiere del conocimiento de la variación de sus propiedades termomecánicas con respecto a la temperatura. Ante las altas temperaturas la fábrica cerámica presenta efectos termomecánicos, como la variación del módulo de Young entre otros, así como la variación de las propiedades del material debidas a la degradación del mismo. En este artículo se describe la variación del módulo de elasticidad de la pieza y el mortero con respecto a altas temperaturas según el estado del conocimiento y se exponen los resultados obtenidos del programa experimental llevado a cabo sobre elementos de fábrica sometidos a altas temperaturas con el fin de observar la variación del módulo de Young con respecto a la temperatura.

  8. Concrete Hinges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2014-01-01

    In the first part of the 20th century concrete hinges developed by Freyssinet and Mesnager were widely tested and implemented in concrete structures. The concrete hinges were used a great deal in closed-spandrel arch bridges. Since such a bridge type has not been competitive for the past 40 years....... The present paper uses the prior research results to optimize a test-setup for concrete hinge testing by means of a universal method taking into account the application of the hinge in an arch structure. 3D CAD is utilized in all steps of the planning to reduce errors during assembly of the parts in the test...

  9. Two innovative solutions based on fibre concrete blocks designed for building substructure

    Science.gov (United States)

    Pazderka, J.; Hájek, P.

    2017-09-01

    Using of fibers in a high-strength concrete allows reduction of the dimensions of small precast concrete elements, which opens up new ways of solution for traditional construction details in buildings. The paper presents two innovative technical solutions for building substructure: The special shaped plinth block from fibre concrete and the fibre concrete elements for new technical solution of ventilated floor. The main advantages of plinth block from fibre concrete blocks (compared with standard plinth solutions) is: easier and faster assembly, higher durability and thanks to the air cavity between the vertical part of the block, the building substructure reduced moisture level of structures under the waterproofing layer and a comprehensive solution to the final surface of building plinth as well as the surface of adjacent terrain. The ventilated floor based on fibre concrete precast blocks is an attractive structural alternative for tackling the problem of increased moisture in masonry in older buildings, lacking a functional waterproof layer in the substructure.

  10. Offshore concrete structures

    International Nuclear Information System (INIS)

    Lamas Pardo, M.; Carral Couce, L. M.

    2011-01-01

    In the offshore industry there are two possible materials for the construction of the hull of a structure; the steel and concrete, with the first one widely used until now, as in the rest of the shiphuidling industry of merchant ships, warships, etc. Materials such as aluminum, GRP or timber areused in small units with lengths lower than 100 m, and in less adverse conditions than in the offshore industry. Nevertheless, some ships/barges have been built of concrete in the past, but have been rather isolated cases which have not changed the practice in the industry. In the First and Second World War were built by the scarcity of materials, while the series of barges by Alfred A. Yee was a rare exception. Other units were also made in concrete, but almost anecdotal. Still, the behaviour of these concrete structures, especially in terms of maintenance, has been excellent. Therefore, the fact that the concrete has not had an adequate reception so far in shipbuilding, does not mean that in will not be the material best suited for the offshore industry in the future. The extra displacement and associated fuel costs in concrete ships have been found prohibitive in the past. But the loss of mobility of a concrete hull in relation to a steel hull can be perfectly offset by the advantages offered by the concrete, as the shipping and offshore industry have very different priorities. One of the main differences in these priorities is in terms of maintenance and resistance to fatigue, precisely where the concrete performs better. ships can easily be dry docked for maintenance and repair, while in the offshore platforms these works have to be done in situ so maintenance and fatigue are crucial to them. Besides these, the concrete has other advantages according to findings of several studies. And although they are interested in the conclusions that the makes as they came from people in the concrete industry, the fact that in recent years concrete offshore unit shave been built

  11. Wood and concrete polymer composites

    International Nuclear Information System (INIS)

    Singer, K.

    1974-01-01

    There are several ways to prepare and use wood and concrete polymer composites. The most important improvements in the case of concrete polymer composites are obtained for compressive and tensile strengths. The progress in this field in United States and other countries is discussed in this rview. (M.S.)

  12. Radon penetration of concrete slab cracks, joints, pipe penetrations, and sealants.

    Science.gov (United States)

    Nielson, K K; Rogers, V C; Holt, R B; Pugh, T D; Grondzik, W A; de Meijer, R J

    1997-10-01

    Radon movement through 12 test slabs with different cracks, pipe penetrations, cold joints, masonry blocks, sealants, and tensile stresses characterized the importance of these anomalous structural domains. Diffusive and advective radon transport were measured with steady-state air pressure differences controlled throughout the deltaP = 0 to 60 Pa range. Diffusion coefficients (deltaP = 0) initially averaged 6.5 x 10(-8) m2 s(-1) among nine slabs with only 8% standard deviation, but increased due to drying by 0.16% per day over a 2-y period to an average of 2.0 x 10(-7) m2 s(-1). An asphalt coating reduced diffusion sixfold but an acrylic surface sealant had no effect. Diffusion was 42 times higher in solid masonry blocks than in concrete and was not affected by small cracks. Advective transport (deltaP slabs (10(-16) m2 permeability), pipe penetrations, and caulked gaps, but was significant for cracks, disturbed pipe penetrations, cold joints, masonry blocks, and concrete under tensile stress. Crack areas calculated to be as small as 10(-7) m2 significantly increased radon advection. Algebraic expressions predict air velocity and effective crack width from enhanced radon transport and air pressures. Masonry blocks, open cracks, and slab cold joints enhance radon penetration but stressed slabs, undisturbed pipe penetrations, and sealed cracks may not.

  13. Finite element analyses of continuous filament ties for masonry applications : final report for the Arquin Corporation.

    Energy Technology Data Exchange (ETDEWEB)

    Quinones, Armando, Sr. (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei

    2008-08-01

    Finite-element analyses were performed to simulate the response of a hypothetical vertical masonry wall subject to different lateral loads with and without continuous horizontal filament ties laid between rows of concrete blocks. A static loading analysis and cost comparison were also performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Simulations of vertical walls subject to static loads representing 100 mph winds (0.2 psi) and a seismic event (0.66 psi) showed that the simulated walls performed similarly and adequately when subject to these loads with and without the ties. Additional simulations and tests are required to assess the performance of actual walls with and without the ties under greater loads and more realistic conditions (e.g., cracks, non-linear response).

  14. NANOMODIFIED CONCRETE

    Directory of Open Access Journals (Sweden)

    B. M. Khroustalev

    2015-01-01

    Full Text Available One of the main directions in construction material science is the development of  next generation concrete that is ultra-dense, high-strength, ultra-porous, high heat efficient, extra corrosion-resistant. Selection of such direction is caused by extreme operational impacts on the concrete, namely: continuously increasing load on the concrete and various dynamics of such loads; the necessity in operation of concrete products in a wide temperature range and their exposure to various chemical and physical effects.The next generation concrete represents high-tech concrete mixtures with additives that takes on and retain the required properties when hardening and being used under any operational conditions. A differential characteristic of the next generation concrete is its complexity that presumes usage of various mineral dispersed components, two- and three fractional fine and coarse aggregates, complex chemical additives, combinations of polymer and iron reinforcement.Design strength and performance properties level of the next generation concrete is achieved by high-quality selection of the composition, proper selection of manufacturing techniques, concrete curing, bringing the quality of concrete items to the required level of technical condition during the operational phase. However, directed formation of its structure is necessary in order to obtain high-tech concrete.Along with the traditional methods for regulation of the next generation concrete structure, modification of concrete while using silica nanoparticles is also considered as a perspective one because the concrete patterning occurs due to introduction of a binder in a mineral matrix. Due to this it is possible to obtain nano-modified materials with completely new properties.The main problem with the creation of nano-modified concrete is a uniform distribution of nano-materials in the volume of the cement matrix which is particularly important in the cases of adding a modifier in

  15. Literature review on the assessment of masonry properties by tests on core samples

    NARCIS (Netherlands)

    Jafari, S.; Esposito, R.; Rots, J.G.; Quist, W.J.; Granneman, S.J.C.; van Hees, R.P.J.

    2017-01-01

    Starting point in this research is to find a quick and non-destructive method to characterize the mechanical properties of existing masonry. Tests on cylindrical cores have been recently introduced as a novel in-situ testing method to identify the properties of existing clay brick masonry.

  16. Two approaches for the analysis of masonry structures : Micro and macro-modeling

    NARCIS (Netherlands)

    Laurenco, P.B.; Rots, J.G.; Blaauwendraad, J.

    1995-01-01

    Two models for the micro- and macro-analysis of masonry structures are presented. For the micromodeling of masonry, an interface failure criterion that includes a straight tension cut-off, the Coulomb friction law and an elliptical cap is proposed. The inelastic behavior includes tensile strength

  17. High Performance Concrete Pavement in Indiana

    OpenAIRE

    Nantung, Tommy E

    2011-01-01

    Until the early 1990s, curling and warping of Portland cement concrete pavement did not concern pavement engineers in many transportation agencies. Since beginning construction of the interstate system in the United States in the late 1950s through the late 1980s, the performance of Portland cement concrete pavement has been associated with properties of concrete as a pavement material. In those years developed standards and design guidelines emphasized better concrete materials and construct...

  18. An efficient Bouc & Wen approach for seismic analysis of masonry tower

    Directory of Open Access Journals (Sweden)

    Luca Facchini

    2014-07-01

    Full Text Available The assessment of existing masonry towers under exceptional loads, such as earthquake loads, requires reliable, expedite and efficient methods of analysis. These approaches should take into account both the randomness that affects the masonry properties (in some cases also the distribution of the elastic parameters and, of course, the nonlinear behavior of masonry. Considering the need of simplified but effective methods to assess the seismic response of such structures, the paper proposes an efficient approach for seismic assessment of masonry towers assuming the material properties as a stochastic field. As a prototype of masonry towers a cantilever beam is analyzed assuming that the first modal shape governs the structural motion. With this hypothesis a nonlinear hysteretic Bouc & Wen model is employed to reproduce the system response which is subsequently employed to evaluate the response bounds. The results of the simplified approach are compared with the results of a finite element model to show the effectiveness of the method.

  19. Non Linear Analyses for the Evaluation of Seismic Behavior of Mixed R.C.-Masonry Structures

    International Nuclear Information System (INIS)

    Liberatore, Laura; Tocci, Cesare; Masiani, Renato

    2008-01-01

    In this work the seismic behavior of masonry buildings with mixed structural system, consisting of perimeter masonry walls and internal r.c. frames, is studied by means of non linear static (pushover) analyses. Several aspects, like the distribution of seismic action between masonry and r.c. elements, the local and global behavior of the structure, the crisis of the connections and the attainment of the ultimate strength of the whole structure are examined. The influence of some parameters, such as the masonry compressive and tensile strength, on the structural behavior is investigated. The numerical analyses are also repeated on a building in which the r.c. internal frames are replaced with masonry walls

  20. Masonry structures built with fictile tubules: Experimental and numerical analyses

    Science.gov (United States)

    Tiberti, Simone; Scuro, Carmelo; Codispoti, Rosamaria; Olivito, Renato S.; Milani, Gabriele

    2017-11-01

    Masonry structures with fictile tubules were a distinctive building technique of the Mediterranean area. This technique dates back to Roman and early Christian times, used to build vaulted constructions and domes with various geometrical forms by virtue of their modular structure. In the present work, experimental tests were carried out to identify the mechanical properties of hollow clay fictile tubules and a possible reinforcing technique for existing buildings employing such elements. The experimental results were then validated by devising and analyzing numerical models with the FE software Abaqus, also aimed at investigating the structural behavior of an arch via linear and nonlinear static analyses.

  1. Seismic Behaviour of Masonry Vault-Slab Structures

    International Nuclear Information System (INIS)

    Chesi, Claudio; Butti, Ferdinando; Ferrari, Marco

    2008-01-01

    Spandrel walls typically play a structural role in masonry buildings, transferring load from a slab to the supporting vault. Some indications are given in the literature on the behaviour of spandrels under the effect of vertical loads, but little attention is given to the effect coming from lateral forces acting on the building. An opportunity to investigate this problem has come from the need of analyzing a monumental building which was damaged by the Nov. 24, 2004 Val Sabbia earthquake in the north of Italy. The finite element model set up for the analysis of the vault-spandrel-slab system is presented and the structural role resulting for the spandrels is discussed

  2. Photocatalyticpaving concrete

    Directory of Open Access Journals (Sweden)

    Lyapidevskaya Ol'ga Borisovna

    2014-02-01

    Full Text Available Today bituminous concrete is a conventional paving material. Among its advantages one can name dustlessness and noiselessness, fine wear (up to 1 mm a year and fine maintainability. As the main disadvantages of this material one can name high slipperiness under humidification, low durability and weather resistance. Besides that, during placement of the bituminous concrete a lot of different air pollutants are emitted, which are harmful for environment and human’s health (they are listed in the paper according to the US Environmental Protection Agency materials. As an alternative, one can use cement-concrete pavement, which is in many ways more efficient than the bituminous concrete. It is proposed to enhance environmental performance of the cement-concrete pavement via usage of photocatalysis. The mechanism of different photocatalytic reactions is described in the paper, namely heterogeneous and homogeneous photocatalysis, photo-induces, photoactivated catalysis and catalytical photoreactions. It is pro-posed to use heterogeneous photocatalysis with titanium dioxide as a photocatalyst. The mechanism of photo oxidation of air contaminants, with the usage of titanium dioxide is2described. The paper sets problems, connected with the sensibilization of TiOto thevisible light (it is proposed to use titanium dioxide, doped with the atoms of certain elements to increase its sensibility to the visible light and with the development of a new photocatalytic paving concrete, which will meet the requirements, specified for paving in the climatic and traffic conditions of the Russian Federation.

  3. Self-Placing Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Certain concrete pours have areas where the congestion of reinforcing bars make placement of concrete almost impossible. Using conventional placing and vibration techniques, the resulting concrete can have considerable honeycombing due to the development of voids. Self-placing concrete is a possible solution to the problem. Also known as self-compactable concrete, self-consolidating concrete, flowable concrete, and non-vibration concrete. These concretes eliminate the need for vibration in a ...

  4. Properties of wastepaper sludge in geopolymer mortars for masonry applications.

    Science.gov (United States)

    Yan, Shiqin; Sagoe-Crentsil, Kwesi

    2012-12-15

    This paper presents the results of an investigation into the use of wastepaper sludge in geopolymer mortar systems for manufacturing construction products. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. Both fresh and hardened geopolymer mortar properties are evaluated for samples incorporating dry wastepaper sludge, and the results indicate potential end-use benefits in building product manufacture. Addition of wastepaper sludge to geopolymer mortar reduces flow properties, primarily due to dry sludge absorbing water from the binder mix. The average 91-day compressive strength of mortar samples incorporating 2.5 wt% and 10 wt% wastepaper sludge respectively retained 92% and 52% of the reference mortar strength. However, contrary to the normal trend of increasing drying shrinkage with increasing paper sludge addition to Portland cement matrices, the corresponding geopolymer drying shrinkage decreased by 34% and 64%. Equally important, the water absorption of hardened geopolymer mortar decreased with increasing paper sludge content at ambient temperatures, providing good prospects of overall potential for wastepaper sludge incorporation in the production of building and masonry elements. The results indicate that, despite its high moisture absorbance due to the organic matter and residual cellulose fibre content, wastepaper sludge appears compatible with geopolymer chemistry, and hence serves as a potential supplementary additive to geopolymer cementitious masonry products. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Fabrication of nanoplate resonating structures via micro-masonry

    International Nuclear Information System (INIS)

    Bhaswara, A; Legrand, B; Mathieu, F; Nicu, L; Leichle, T; Keum, H; Rhee, S; Kim, S

    2014-01-01

    Advantages of using nanoscale membrane and plate resonators over more common cantilever shapes include higher quality factor (Q factor) for an equivalent mass and better suitability to mass sensing applications in fluid. Unfortunately, the current fabrication methods used to obtain such membranes and plates are limited in terms of materials and thickness range, and can potentially cause stiction. This study presents a new method to fabricate nanoplate resonating structures based on micro-masonry, which is the advanced form of the transfer printing technique. Nanoplate resonators were fabricated by transfer printing 0.34 µm thick square-shaped silicon plates by means of polydimethylsiloxane microtip stamps on top of silicon oxide base structures displaying 20 µm diameter cavities, followed by a thermal annealing step to create a rigid bond. Typical resulting suspended structures display vibration characteristics, i.e. a resonance frequency of a few MHz and Q factors above 10 in air at atmospheric pressure, which are in accordance with theory. Moreover, the presented fabrication method enables the realization of multiple suspended structures in a single step and on the same single base, without mechanical crosstalk between the resonators. This work thus demonstrates the suitability and the advantages of the micro-masonry technique for the fabrication of plate resonators for mass sensing purpose. (paper)

  6. Fiberglass Grids as Sustainable Reinforcement of Historic Masonry

    Science.gov (United States)

    Righetti, Luca; Edmondson, Vikki; Corradi, Marco; Borri, Antonio

    2016-01-01

    Fiber-reinforced composite (FRP) materials have gained an increasing success, mostly for strengthening, retrofitting and repair of existing historic masonry structures and may cause a significant enhancement of the mechanical properties of the reinforced members. This article summarizes the results of previous experimental activities aimed at investigating the effectiveness of GFRP (Glass Fiber Reinforced Polymers) grids embedded into an inorganic mortar to reinforce historic masonry. The paper also presents innovative results on the relationship between the durability and the governing material properties of GFRP grids. Measurements of the tensile strength were made using specimens cut off from GFRP grids before and after ageing in aqueous solution. The tensile strength of a commercially available GFRP grid has been tested after up 450 days of storage in deionized water and NaCl solution. A degradation in tensile strength and Young’s modulus up to 30.2% and 13.2% was recorded, respectively. This degradation indicated that extended storage in a wet environment may cause a decrease in the mechanical properties. PMID:28773725

  7. Experimental Analysis of Dynamic Effects of FRP Reinforced Masonry Vaults

    Science.gov (United States)

    Corradi, Marco; Borri, Antonio; Castori, Giulio; Coventry, Kathryn

    2015-01-01

    An increasing interest in the preservation of historic structures has produced a need for new methods for reinforcing curved masonry structures, such as arches and vaults. These structures are generally very ancient, have geometries and materials which are poorly defined and have been exposed to long-term historical movements and actions. Consequently, they are often in need of repair or reinforcement. This article presents the results of an experimental study carried out in the laboratory and during on-site testing to investigate the behaviour of brick masonry vaults under dynamic loading strengthened with FRPs (Fiber Reinforced Polymers). For the laboratory tests, the brick vaults were built with solid sanded clay bricks and weak mortar and were tested under dynamic loading. The experimental tests were designed to facilitate analysis of the dynamic behaviour of undamaged, damaged and reinforced vaulted structures. On-site tests were carried out on an earthquake-damaged thin brick vault of an 18th century aristocratic residence in the city of L’Aquila, Italy. The provision of FRP reinforcement is shown to re-establish elastic behavior previously compromised by time induced damage in the vaults. PMID:28793697

  8. Earthquake response of heavily damaged historical masonry mosques after restoration

    Science.gov (United States)

    Altunışık, Ahmet Can; Fuat Genç, Ali

    2017-10-01

    Restoration works have been accelerated substantially in Turkey in the last decade. Many historical buildings, mosques, minaret, bridges, towers and structures have been restored. With these restorations an important issue arises, namely how restoration work affects the structure. For this reason, we aimed to investigate the restoration effect on the earthquake response of a historical masonry mosque considering the openings on the masonry dome. For this purpose, we used the Hüsrev Pasha Mosque, which is located in the Ortakapı district in the old city of Van, Turkey. The region of Van is in an active seismic zone; therefore, earthquake analyses were performed in this study. Firstly a finite element model of the mosque was constructed considering the restoration drawings and 16 window openings on the dome. Then model was constructed with eight window openings. Structural analyses were performed under dead load and earthquake load, and the mode superposition method was used in analyses. Maximum displacements, maximum-minimum principal stresses and shear stresses are given with contours diagrams. The results are analyzed according to Turkish Earthquake Code (TEC, 2007) and compared between 8 and 16 window openings cases. The results show that reduction of the window openings affected the structural behavior of the mosque positively.

  9. Experimental Analysis of Dynamic Effects of FRP Reinforced Masonry Vaults

    Directory of Open Access Journals (Sweden)

    Marco Corradi

    2015-11-01

    Full Text Available An increasing interest in the preservation of historic structures has produced a need for new methods for reinforcing curved masonry structures, such as arches and vaults. These structures are generally very ancient, have geometries and materials which are poorly defined and have been exposed to long-term historical movements and actions. Consequently, they are often in need of repair or reinforcement. This article presents the results of an experimental study carried out in the laboratory and during on-site testing to investigate the behaviour of brick masonry vaults under dynamic loading strengthened with FRPs (Fiber Reinforced Polymers. For the laboratory tests, the brick vaults were built with solid sanded clay bricks and weak mortar and were tested under dynamic loading. The experimental tests were designed to facilitate analysis of the dynamic behaviour of undamaged, damaged and reinforced vaulted structures. On-site tests were carried out on an earthquake-damaged thin brick vault of an 18th century aristocratic residence in the city of L’Aquila, Italy. The provision of FRP reinforcement is shown to re-establish elastic behavior previously compromised by time induced damage in the vaults.

  10. Experimental Analysis of Dynamic Effects of FRP Reinforced Masonry Vaults.

    Science.gov (United States)

    Corradi, Marco; Borri, Antonio; Castori, Giulio; Coventry, Kathryn

    2015-11-27

    An increasing interest in the preservation of historic structures has produced a need for new methods for reinforcing curved masonry structures, such as arches and vaults. These structures are generally very ancient, have geometries and materials which are poorly defined and have been exposed to long-term historical movements and actions. Consequently, they are often in need of repair or reinforcement. This article presents the results of an experimental study carried out in the laboratory and during on-site testing to investigate the behaviour of brick masonry vaults under dynamic loading strengthened with FRPs (Fiber Reinforced Polymers). For the laboratory tests, the brick vaults were built with solid sanded clay bricks and weak mortar and were tested under dynamic loading. The experimental tests were designed to facilitate analysis of the dynamic behaviour of undamaged, damaged and reinforced vaulted structures. On-site tests were carried out on an earthquake-damaged thin brick vault of an 18th century aristocratic residence in the city of L'Aquila, Italy. The provision of FRP reinforcement is shown to re-establish elastic behavior previously compromised by time induced damage in the vaults.

  11. Fiberglass Grids as Sustainable Reinforcement of Historic Masonry

    Directory of Open Access Journals (Sweden)

    Luca Righetti

    2016-07-01

    Full Text Available Fiber-reinforced composite (FRP materials have gained an increasing success, mostly for strengthening, retrofitting and repair of existing historic masonry structures and may cause a significant enhancement of the mechanical properties of the reinforced members. This article summarizes the results of previous experimental activities aimed at investigating the effectiveness of GFRP (Glass Fiber Reinforced Polymers grids embedded into an inorganic mortar to reinforce historic masonry. The paper also presents innovative results on the relationship between the durability and the governing material properties of GFRP grids. Measurements of the tensile strength were made using specimens cut off from GFRP grids before and after ageing in aqueous solution. The tensile strength of a commercially available GFRP grid has been tested after up 450 days of storage in deionized water and NaCl solution. A degradation in tensile strength and Young’s modulus up to 30.2% and 13.2% was recorded, respectively. This degradation indicated that extended storage in a wet environment may cause a decrease in the mechanical properties.

  12. a Procedural Solution to Model Roman Masonry Structures

    Science.gov (United States)

    Cappellini, V.; Saleri, R.; Stefani, C.; Nony, N.; De Luca, L.

    2013-07-01

    The paper will describe a new approach based on the development of a procedural modelling methodology for archaeological data representation. This is a custom-designed solution based on the recognition of the rules belonging to the construction methods used in roman times. We have conceived a tool for 3D reconstruction of masonry structures starting from photogrammetric surveying. Our protocol considers different steps. Firstly we have focused on the classification of opus based on the basic interconnections that can lead to a descriptive system used for their unequivocal identification and design. Secondly, we have chosen an automatic, accurate, flexible and open-source photogrammetric pipeline named Pastis Apero Micmac - PAM, developed by IGN (Paris). We have employed it to generate ortho-images from non-oriented images, using a user-friendly interface implemented by CNRS Marseille (France). Thirdly, the masonry elements are created in parametric and interactive way, and finally they are adapted to the photogrammetric data. The presented application, currently under construction, is developed with an open source programming language called Processing, useful for visual, animated or static, 2D or 3D, interactive creations. Using this computer language, a Java environment has been developed. Therefore, even if the procedural modelling reveals an accuracy level inferior to the one obtained by manual modelling (brick by brick), this method can be useful when taking into account the static evaluation on buildings (requiring quantitative aspects) and metric measures for restoration purposes.

  13. Concreting organization during Chernobylsk NPP construction

    International Nuclear Information System (INIS)

    Lysyuk, R.I.; Kareva, A.P.

    1984-01-01

    Conreting organization during the Chernobylsk NPP construction is described. Processes of extra heavy concrete production and placement, which specific mass constitutes 4t/m 3 at the age of 28 days wiath metallic aggregates and 3.3-3.5 t/m 3 at the same age without aggregates, are considered in short. Basic characteristics of this concrete are presented. At the 4th power unit labour contents for construction works were a 1.5 times lower as compared to the 3rd power unit erection. This progress was achieved by round-the-clock operation of the concrete plant with the 800 m 3 /day output and also by utilization of special equipment for mechanized concrete placement: concrete pumps, automatic concrete mixer, manipulators and concrete pipelines

  14. Mixture optimization of cement treated demolition waste with recycled masonry and concrete

    NARCIS (Netherlands)

    Xuan, D.X.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.H,

    2011-01-01

    Due to environmental reasons and the shortage of natural resources, it is greatly valuable to recycle construction and demolition waste (CDW) as much as possible. One of effective ways to reuse more CDW is to produce a cemented road base material. The recycled CDW however is a mix of recycled

  15. The influence of construction measurement and structure storey on seismic performance of masonry structure

    Science.gov (United States)

    Sun, Baitao; Zhao, Hexian; Yan, Peilei

    2017-08-01

    The damage of masonry structures in earthquakes is generally more severe than other structures. Through the analysis of two typical earthquake damage buildings in the Wenchuan earthquake in Xuankou middle school, we found that the number of storeys and the construction measures had great influence on the seismic performance of masonry structures. This paper takes a teachers’ dormitory in Xuankou middle school as an example, selected the structure arrangement and storey number as two independent variables to design working conditions. Finally we researched on the seismic performance difference of masonry structure under two variables by finite element analysis method.

  16. Experimental and numerical analysis of pre-compressed masonry walls in two-way-bending with second order effects

    Energy Technology Data Exchange (ETDEWEB)

    Milani, Gabriele, E-mail: milani@stru.polimi.it [Department of Architecture, Built Environment and Construction Engineering (ABC), Politecnico diMilano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Olivito, Renato S. [Dipartimento di Ingegneria Civile - Università della Calabria Via P Bucci 39 B - 87036 RENDE (CS) (Italy); Tralli, Antonio [Department of Engineering, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy)

    2014-10-06

    The buckling behavior of slender unreinforced masonry (URM) walls subjected to axial compression and out-of-plane lateral loads is investigated through a combined experimental and numerical homogenizedapproach. After a preliminary analysis performed on a unit cell meshed by means of elastic FEs and non-linear interfaces, macroscopic moment-curvature diagrams so obtained are implemented at a structural level, discretizing masonry by means of rigid triangular elements and non-linear interfaces. The non-linear incremental response of the structure is accounted for a specific quadratic programming routine. In parallel, a wide experimental campaign is conducted on walls in two way bending, with the double aim of both validating the numerical model and investigating the behavior of walls that may not be reduced to simple cantilevers or simply supported beams. Panels investigated are dry-joint in scale square walls simply supported at the base and on a vertical edge, exhibiting the classical Rondelet’s mechanism. The results obtained are compared with those provided by the numerical model.

  17. Experimental and numerical analysis of pre-compressed masonry walls in two-way-bending with second order effects

    International Nuclear Information System (INIS)

    Milani, Gabriele; Olivito, Renato S.; Tralli, Antonio

    2014-01-01

    The buckling behavior of slender unreinforced masonry (URM) walls subjected to axial compression and out-of-plane lateral loads is investigated through a combined experimental and numerical homogenizedapproach. After a preliminary analysis performed on a unit cell meshed by means of elastic FEs and non-linear interfaces, macroscopic moment-curvature diagrams so obtained are implemented at a structural level, discretizing masonry by means of rigid triangular elements and non-linear interfaces. The non-linear incremental response of the structure is accounted for a specific quadratic programming routine. In parallel, a wide experimental campaign is conducted on walls in two way bending, with the double aim of both validating the numerical model and investigating the behavior of walls that may not be reduced to simple cantilevers or simply supported beams. Panels investigated are dry-joint in scale square walls simply supported at the base and on a vertical edge, exhibiting the classical Rondelet’s mechanism. The results obtained are compared with those provided by the numerical model

  18. Experimental study of masonry wall exposed to blast loading

    Directory of Open Access Journals (Sweden)

    Ahmad, S.

    2014-03-01

    Full Text Available The challenge of protecting the nation against the attack of terrorism has raised the importance to explore the understanding of building materials against the explosion. Unlike most of the building materials, brick masonry materials offer relatively small resistance against blast loading. In this research, a brick masonry wall was exposed to varying blast load at different scaled distances. Six tests with different amounts of explosives at various distances were carried out. Pressure time history, acceleration time history and strain at specific location were measured. The parameters measured from experimental pressure time history and acceleration time history is compared with those determined by ConWep to establish the correlations between experimental determined records and ConWep values. The experimental results were also compared with some researchers. These correlations may assist in understanding the behaviour of masonry structures subjected to explosive loading.Con el reto que supone proteger a la nación contra atentados terroristas se ha visto acrecentada la importancia de conocer el comportamiento de materiales de construcción cuando se someten a una carga explosiva. Al contrario de la mayoría de los materiales, las fábricas de ladrillo ofrecen poca resistencia a dichas cargas. En el presente trabajo, se estudió el comportamiento de una fábrica de ladrillo ante cargas explosivas colocadas a diferentes distancias del muro. Se realizaron seis pruebas con explosivos de potencias distintas y a diferentes distancias. Se trazaron las curvas presión-tiempo y aceleración-tiempo, midiéndose asimismo la deformación en un punto concreto. Los valores experimentales de las curvas presión-tiempo y aceleración-tiempo se compararon con los que se calcularon con la ayuda de la aplicación informática ConWep a fin de establecer las correlaciones entre ambos conjuntos de resultados. También se compararon los resultados experimentales

  19. Historic Concrete : From Concrete Repair to Concrete Conservation

    NARCIS (Netherlands)

    Heinemann, H.A.

    2013-01-01

    Concrete like materials were already applied during the Roman Empire. After the decline of the Roman Empire, a wide scale application of concrete only reappeared in the 19th century. Here lies also the origin of modern (reinforced) concrete. Since then, both concrete application and composition have

  20. Comparative study on diagonal equivalent methods of masonry infill panel

    Science.gov (United States)

    Amalia, Aniendhita Rizki; Iranata, Data

    2017-06-01

    Infrastructure construction in earthquake prone area needs good design process, including modeling a structure in a correct way to reduce damages caused by an earthquake. Earthquakes cause many damages e.g. collapsed buildings that are dangerous. An incorrect modeling in design process certainly affects the structure's ability in responding to load, i.e. an earthquake load, and it needs to be paid attention to in order to reduce damages and fatalities. A correct modeling considers every aspect that affects the strength of a building, including stiffness of resisting lateral loads caused by an earthquake. Most of structural analyses still use open frame method that does not consider the effect of stiffness of masonry panel to the stiffness and strength of the whole structure. Effect of masonry panel is usually not included in design process, but the presence of this panel greatly affects behavior of the building in responding to an earthquake. In worst case scenario, it can even cause the building to collapse as what has been reported after great earthquakes worldwide. Modeling a structure with masonry panel as consideration can be performed by designing the panel as compression brace or shell element. In designing masonry panel as a compression brace, there are fourteen methods popular to be used by structure designers formulated by Saneinejad-Hobbs, Holmes, Stafford-Smith, Mainstones, Mainstones-Weeks, Bazan-Meli, Liauw Kwan, Paulay and Priestley, FEMA 356, Durani Luo, Hendry, Al-Chaar, Papia and Chen-Iranata. Every method has its own equation and parameters to use, therefore the model of every method was compared to results of experimental test to see which one gives closer values. Moreover, those methods also need to be compared to the open frame to see if they can result values within limits. Experimental test that was used in comparing all methods was taken from Mehrabi's research (Fig. 1), which was a prototype of a frame in a structure with 0.5 scale and the

  1. Analysis of Static Load Test of a Masonry Arch Bridge

    Science.gov (United States)

    Shi, Jing-xian; Fang, Tian-tian; Luo, Sheng

    2018-03-01

    In order to know whether the carrying capacity of the masonry arch bridge built in the 1980s on the shipping channel entering and coming out of the factory of a cement company can meet the current requirements of Level II Load of highway, through the equivalent load distribution of the test vehicle according to the current design specifications, this paper conducted the load test, evaluated the bearing capacity of the in-service stone arch bridge, and made theoretical analysis combined with Midas Civil. The results showed that under the most unfavorable load conditions the measured strain and deflection of the test sections were less than the calculated values, the bridge was in the elastic stage under the design load; the structural strength and stiffness of the bridge had a certain degree of prosperity, and under the in the current conditions of Level II load of highway, the bridge structure was in a safe state.

  2. Assessment of historical masonry pillars reinforced by CFRP strips

    Science.gov (United States)

    Fedele, Roberto; Rosati, Giampaolo; Biolzi, Luigi; Cattaneo, Sara

    2014-10-01

    In this methodological study, the ultimate response of masonry pillars strengthened by externally bonded Carbon Fiber Reinforced Polymer (CFRP) was investigated. Historical bricks were derived from a XVII century rural building, whilst a high strength mortar was utilized for the joints. The conventional experimental information, concerning the overall reaction force and relative displacements provided by "point" sensors (LVDTs and clip gauge), were herein enriched with no-contact, full-field kinematic measurements provided by 2D Digital Image Correlation (2D DIC). Experimental information were critically compared with prediction provided by an advanced three-dimensional models, based on nonlinear finite elements under the simplifying assumption of perfect adhesion between the reinforcement and the support.

  3. Calibration of brick masonry partial safety factors for the South African Code

    CSIR Research Space (South Africa)

    Mahachi, J

    2007-09-01

    Full Text Available The current South African Code of Practice for structural use of masonry uses four partial safety factors gm, for materials depending on construction control and quality control. With the boom in the construction industry, new entrants...

  4. Seismic Response of a Half-Scale Masonry Building with Flexible Diaphragms

    National Research Council Canada - National Science Library

    Sweeney, Steven C; Horney, Matthew A; Orton, Sarah L

    2005-01-01

    Unreinforced masonry (URM) buildings constructed on Army installations before the development of modern seismic codes may be susceptible to earthquake damage and therefore could benefit from seismic mitigation measures...

  5. Performance of masonry buildings during the 20 and 27 December 2007 Bala (Ankara earthquakes in Turkey

    Directory of Open Access Journals (Sweden)

    S. Adanur

    2010-12-01

    Full Text Available This paper evaluates the performance of masonry buildings during the 20 and 27 December 2007 Bala (Ankara earthquakes. Bala is a township located 50 km southeast from Ankara city in Turkey. The majority of the buildings in the affected region are built in masonry. Most of masonry buildings were formed with random or coursed stone and mud brick walls without any reinforcement. Many of these buildings were damaged or had collapsed. The cracking and failure patterns of the buildings are examined and interpreted according to current provisions for earthquake resistance of masonry structures. The damages are due to several reasons such as poor construction quality and poor workmanship of the buildings. In addition to these reasons, the two earthquakes hit the buildings within seven days, causing progressive damage.

  6. Global analyses of historical masonry buildings: Equivalent frame vs. 3D solid models

    Science.gov (United States)

    Clementi, Francesco; Mezzapelle, Pardo Antonio; Cocchi, Gianmichele; Lenci, Stefano

    2017-07-01

    The paper analyses the seismic vulnerability of two different masonry buildings. It provides both an advanced 3D modelling with solid elements and an equivalent frame modelling. The global structural behaviour and the dynamic properties of the compound have been evaluated using the Finite Element Modelling (FEM) technique, where the nonlinear behaviour of masonry has been taken into account by proper constitutive assumptions. A sensitivity analysis is done to evaluate the effect of the choice of the structural models.

  7. Mechanical characterization of historical masonry by means of minor destructive techniques

    OpenAIRE

    Pelà, Luca; Roca Fabregat, Pedro

    2016-01-01

    One of the main difficulties encountered in the study of existing masonry structures is found in the adequate characterization of the mechanical properties of the material. The typical features of common masonry structural members (thin bed joints, poor unitmortar bond) make it extremely difficult to obtain sufficiently large-size samples of the material components (mortar, brick or stone) and the composite allowing the application of standardized or conventional experimental tests. A possibl...

  8. Laboratory fatigue evaluation of continuously fiber-reinforced concrete pavement.

    Science.gov (United States)

    2013-09-01

    Portland cement concrete (PCC) is the worlds most versatile construction material. PCC has : been in use in the United States for over 100 years. PCC pavement is generally constructed as : either continually reinforced concrete pavement (CRCP) or ...

  9. Aspects of alteration of masonry historical buildings without ring beam of floor slabs

    Directory of Open Access Journals (Sweden)

    Ryszard Chmielewski

    2016-12-01

    Full Text Available Some problems of alteration for building structures of a conventional masonry for which working lifetime is approaching or has exceeded the expected design life are presented. In the course of these works, non-bearing masonry walls are often removed and as a result significant damages to supporting structures are often made, and in extreme cases even building collapses. Building surveyors who prepare a structural appraisal for technical reports of damaged masonry structures, as a solution to the problem, recommend sometimes to make only surface reinforcement of damaged walls. The question of significant change in the load distribution in alteration for buildings of conventional design is complex and in some cases above the recommended surface repairs may not be sufficient to ensure structural reliability or the safety of buildings exploitation. The paper proposes a scope of evaluation and structural analysis of a building, which allows to properly determine the range of the existing threats, and on this basis to carry out adequate repair of damaged masonry structures, including structural strengthening.[b]Keywords:[/b] masonry structures, buildings without ring beam of floor slabs, damages of masonry walls, structural failures and collapses

  10. Properties of concretes produced with waste concrete aggregate

    International Nuclear Information System (INIS)

    Topcu, Ilker Bekir; Sengel, Selim

    2004-01-01

    An environmentally friendly approach to the disposal of waste materials, a difficult issue to cope with in today's world, would only be possible through a useful recycling process. For this reason, we suggest that clearing the debris from destroyed buildings in such a way as to obtain waste concrete aggregates (WCA) to be reused in concrete production could well be a partial solution to environmental pollution. For this study, the physical and mechanical properties along with their freeze-thaw durability of concrete produced with WCAs were investigated and test results presented. While experimenting with fresh and hardened concrete, mixtures containing recycled concrete aggregates in amounts of 30%, 50%, 70%, and 100% were prepared. Afterward, these mixtures underwent freeze-thaw cycles. As a result, we found out that C16-quality concrete could be produced using less then 30% C14-quality WCA. Moreover, it was observed that the unit weight, workability, and durability of the concretes produced through WCA decreased in inverse proportion to their endurance for freeze-thaw cycle

  11. High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Traian Oneţ

    2009-01-01

    Full Text Available The paper presents the last studies and researches accomplished in Cluj-Napoca related to high performance concrete, high strength concrete and self compacting concrete. The purpose of this paper is to raid upon the advantages and inconveniences when a particular concrete type is used. Two concrete recipes are presented, namely for the concrete used in rigid pavement for roads and another one for self-compacting concrete.

  12. Technology Demonstration of Wet Abrasive Blasting for Removal of Lead- and Asbestos-Containing Paint

    National Research Council Canada - National Science Library

    Race, Timothy

    2003-01-01

    ...). This technology demonstration showed that wet blasting using an engineered abrasive can safely and effectively remove lead- and asbestos-containing paint from exterior concrete masonry unit walls...

  13. Repair and Strengthening by Use of Superficial Fixed Laminates of Cracked Masonry Walls Sheared Horizontally-Laboratory Tests

    International Nuclear Information System (INIS)

    Kubica, Jan; Kwiecien, Arkadiusz; Zajac, Boguslaw

    2008-01-01

    There are many methods of crack repairing in masonry structures. One of them is repair and strengthening by using of superficial fixed laminates, especially in case of masonry walls with plastering on their both sides. The initial laboratory tests of three different types of strengthening of diagonal cracked masonry wallettes are presented. Tests concerned three clay brick masonry walls subjected to horizontal shearing with two levels of precompression and strengthened by flexible polymer injection, superficial glass fixed by polymer fibre laminate plates and using of CRFP strips stiff fixed to the wall surface by polymer and stiff resin epoxy fixing are presented and discussed

  14. Lightweight concrete modification factor for shear friction.

    Science.gov (United States)

    2013-10-01

    This report describes the results of a study initiated to examine the influence of concrete unit weight on the direct shear transfer across an interface of concretes cast at different times. This type of interface is common with structural precast co...

  15. Crablock Concrete Breakwater Armour Unit

    CSIR Research Space (South Africa)

    Phelp, D

    2012-02-01

    Full Text Available During cyclone Gonu, a category 5 storm, which impacted the east coast of Oman in June 2007, a number of small craft harbours were severly damaged. Most of the breakwater structures were armoured with various sizes of rock protection. The Al Masaood...

  16. Concrete evidence

    Energy Technology Data Exchange (ETDEWEB)

    Provis, J.; Duxson, P.; van Deventer, J. [University of Melbourne, Vic. (Australia)

    2008-11-15

    The time is right for a revolution in the cement industry which is responsible for 5-8% of all human-derived carbon dioxide emissions. Zeobond, an Australian company, has developed E-Crete which is a geopolymer concrete using fly ash and blast furnace slags which reduces CO{sub 2} emissions by 80% from the 0.67t of CO{sub 2} per ton of cement emitted by the Australian triple blend of cement, fly ash and slag. The article discusses the products development, standards for cements and challenges to the commercialization of E-Crete. 5 refs., 3 figs.

  17. Seismic performance assessment of three masonry churches through FE simulations

    Science.gov (United States)

    Milani, Gabriele; Shehu, Rafael; Valente, Marco

    2017-07-01

    The paper presents some seismic analyses on three masonry churches located in Emilia-Romagna (Italy), recently stricken by a devastating earthquake sequence from 20th to 29th May 2012. These churches have a similar geometrical configuration, consisting of three naves, a central colonnade and a simple apse. Limit analyses are conducted on the most important macro-elements of the structure and a full investigation of the churches is carried out by means of the commercial FE Code SAP2000, in both linear and non-linear ranges. Two accelerograms are considered: one is defined in accordance with Italian code response spectrum and the other is based on a natural record of the 29th May earthquake. For both scenarios, the seismic behaviour of the churches is analysed in detail and some vulnerability considerations are drawn. A remarkable consistency is found between limit analyses of macro-elements and response spectrum analyses, whilst some discrepancies can be noted for non-linear dynamic analyses. The results put in evidence the insufficient strength of the apses for shear actions, the columns of the naves for bending moments, the façade for overturning and the triumphal arch for the formation of an in-plane four hinges mechanism.

  18. System identification of timber masonry walls using shaking table test

    Science.gov (United States)

    Roy, Timir B.; Guerreiro, Luis; Bagchi, Ashutosh

    2017-04-01

    Dynamic study is important in order to design, repair and rehabilitation of structures. It has played an important role in the behavior characterization of structures; such as: bridges, dams, high rise buildings etc. There had been substantial development in this area over the last few decades, especially in the field of dynamic identification techniques of structural systems. Frequency Domain Decomposition (FDD) and Time Domain Decomposition are most commonly used methods to identify modal parameters; such as: natural frequency, modal damping and mode shape. The focus of the present research is to study the dynamic characteristics of typical timber masonry walls commonly used in Portugal. For that purpose, a multi-storey structural prototype of such wall has been tested on a seismic shake table at the National Laboratory for Civil Engineering, Portugal (LNEC). Signal processing has been performed of the output response, which is collected from the shaking table experiment of the prototype using accelerometers. In the present work signal processing of the output response, based on the input response has been done in two ways: FDD and Stochastic Subspace Identification (SSI). In order to estimate the values of the modal parameters, algorithms for FDD are formulated and parametric functions for the SSI are computed. Finally, estimated values from both the methods are compared to measure the accuracy of both the techniques.

  19. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1" to 1 1/2"), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  20. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States)

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1” to 1 ½”), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  1. Properties of Hydrophilic Mineral Wool for Desalination of Historical Masonry

    Directory of Open Access Journals (Sweden)

    Iñigo ANTEPARA

    2016-05-01

    Full Text Available Hydrophilic mineral wool (HMW is considered as a possible alternative to the commonly used cellulose in desalination of historical masonry. HMW also allows water and salt solutions transport along the hydrophilic fibres, which is the necessary condition for its possible application for desalination measures, but contrary to cellulose it is inorganic material, which reduces maintenance of the poultice. On this account, the hygric transport and storage properties of newly developed HMW is determined in the paper. In order to get detailed information on HMW performance, its thermal properties are measured as well. For its basic characterization, bulk density, matrix density, saturation moisture and salt content, and apparent total open porosity are accessed. The results are in good agreement with those published in literature for similar types of HMW. The process of drying of three different types of sandstone, as typical materials frequently used in historical buildings, using HMW board is monitored to analyse the practical applicability of the proposed desalination treatment. The obtained results show that HMW slows the drying process. However, the final level of drying is the same as without the HMW, which indicates the possible applicability of studied HMW for desalination purposes.

  2. Concrete construction engineering handbook

    CERN Document Server

    Nawy, Edward G

    2008-01-01

    Provides coverage of concrete construction engineering and technology. This work features discussions focusing on: the advances in engineered concrete materials; reinforced concrete construction; specialized construction techniques; and, design recommendations for high performance.

  3. Finite element nonlinear analysis of high-rise unreinforced masonry building

    Directory of Open Access Journals (Sweden)

    A.H. Akhaveissy

    Full Text Available A simple efficient algorithm based on compressive diagonal strength of unreinforced masonry walls is presented to determine capacity curve of unreinforced masonry building. The compressive strength is calculated based on a new close form solution. The new close form solution is determined based on predicted results using interface elements for modeling of mortar joints. Finite element method with two-noded linear elements is used for analyses. Different masonry structures, including low- and high-rise unreinforced masonry buildings, are analyzed using the new closed-form solution and the presented algorithm. A comparison of results of the present work with experimental data and other methods similar to the discrete element method show proper accuracy of the analyses in the present work. Consequently, the closed form solution with proposed algorithm can be used to satisfactorily analyze unreinforced masonry structures to predict the ultimate base shear force and the pushover curve. Hence, practicing engineers can determine the behavior of an URM building and its performance level with proper accuracy under seismic excitation using concepts described in the present work.

  4. Analyzing crack development pattern of masonry structure in seismic oscillation by digital photography

    Science.gov (United States)

    Zhang, Guojian; Yu, Chengxin; Ding, Xinhua

    2018-01-01

    In this study, digital photography is used to monitor the instantaneous deformation of a masonry wall in seismic oscillation. In order to obtain higher measurement accuracy, the image matching-time baseline parallax method (IM-TBPM) is used to correct errors caused by the change of intrinsic and extrinsic parameters of digital cameras. Results show that the average errors of control point C5 are 0.79mm, 0.44mm and 0.96mm in X, Z and comprehensive direction, respectively. The average errors of control point C6 are 0.49mm, 0.44mm and 0.71mm in X, Z and comprehensive direction, respectively. These suggest that IM-TBPM can meet the accuracy requirements of instantaneous deformation monitoring. In seismic oscillation the middle to lower of the masonry wall develops cracks firstly. Then the shear failure occurs on the middle of masonry wall. This study provides technical basis for analyzing the crack development pattern of masonry structure in seismic oscillation and have significant implications for improved construction of masonry structures in earthquake prone areas.

  5. Strengthening of Masonry Columns with BFRCM or with Steel Wires: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Marinella Fossetti

    2016-05-01

    Full Text Available Nowadays, innovative materials are more frequently adopted for strengthening historical constructions and masonry structures. The target of these techniques is to improve the structural efficiency with retrofitting methods while having a reduced aesthetical impact. In particular, the use of basalt fiber together with a cementitious matrix emerges as a new technique. This kind of fiber is obtained by basalt rock without other components, and consequently it could be considered a natural material, compatible with masonry. Another innovative technique for strengthening masonry columns consists of applying steel wires in the correspondence of mortar joints. Both techniques have been recently proposed and some aspects of their structural performances are still open. This paper presents the results of an experimental study on the compressive behavior of clay brick masonry columns reinforced either with Basalt Fiber–Reinforced Cementitious Matrix (BFRCM or with steel wire collaring. Uniaxial compressive tests were performed on eight retrofitted columns and four control specimens until failure. Two masonry grades were considered by varying the mix used for the mortar. Results are presented and discussed in terms of axial stress-strain curves, failure modes and crack patterns of tested specimens. Comparisons with unreinforced columns show the capability of these techniques in increasing ductility with limited strength enhancements.

  6. Rubble masonry response under cyclic actions: The experience of L’Aquila city (Italy)

    International Nuclear Information System (INIS)

    Fonti, Roberta; Barthel, Rainer; Formisano, Antonio; Borri, Antonio; Candela, Michele

    2015-01-01

    Several methods of analysis are available in engineering practice to study old masonry constructions. Two commonly used approaches in the field of seismic engineering are global and local analyses. Despite several years of research in this field, the various methodologies suffer from a lack of comprehensive experimental validation. This is mainly due to the difficulty in simulating the many different kinds of masonry and, accordingly, the non-linear response under horizontal actions. This issue can be addressed by examining the local response of isolated panels under monotonic and/or alternate actions. Different testing methodologies are commonly used to identify the local response of old masonry. These range from simplified pull-out tests to sophisticated in-plane monotonic tests. However, there is a lack of both knowledge and critical comparison between experimental validations and numerical simulations. This is mainly due to the difficulties in implementing irregular settings within both simplified and advanced numerical analyses. Similarly, the simulation of degradation effects within laboratory tests is difficult with respect to old masonry in-situ boundary conditions. Numerical models, particularly on rubble masonry, are commonly simplified. They are mainly based on a kinematic chain of rigid blocks able to perform different “modes of damage” of structures subjected to horizontal actions. This paper presents an innovative methodology for testing; its aim is to identify a simplified model for out-of-plane response of rubbleworks with respect to the experimental evidence. The case study of L’Aquila district is discussed

  7. Rubble masonry response under cyclic actions: The experience of L’Aquila city (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Fonti, Roberta, E-mail: roberta.fonti@tum.de; Barthel, Rainer, E-mail: r.barthel@lrz.tu-muenchen.de [TUM University, Chair of Structural Design, Arcisstraße 21, 80333 Munich (Germany); Formisano, Antonio, E-mail: antoform@unina.it [University of Naples “Federico II”, DIST Department, P.le V. Tecchio, 80, 80125 Naples (Italy); Borri, Antonio, E-mail: antonio.borri@unipg.it [University of Perugia, Department of Engineering, Via G. Duranti 95, 06125 Perugia (Italy); Candela, Michele, E-mail: ing.mcandela@libero.it [University of Reggio Calabria, PAU Department, Salita Melissari 1, 89124 Reggio Calabria (Italy)

    2015-12-31

    Several methods of analysis are available in engineering practice to study old masonry constructions. Two commonly used approaches in the field of seismic engineering are global and local analyses. Despite several years of research in this field, the various methodologies suffer from a lack of comprehensive experimental validation. This is mainly due to the difficulty in simulating the many different kinds of masonry and, accordingly, the non-linear response under horizontal actions. This issue can be addressed by examining the local response of isolated panels under monotonic and/or alternate actions. Different testing methodologies are commonly used to identify the local response of old masonry. These range from simplified pull-out tests to sophisticated in-plane monotonic tests. However, there is a lack of both knowledge and critical comparison between experimental validations and numerical simulations. This is mainly due to the difficulties in implementing irregular settings within both simplified and advanced numerical analyses. Similarly, the simulation of degradation effects within laboratory tests is difficult with respect to old masonry in-situ boundary conditions. Numerical models, particularly on rubble masonry, are commonly simplified. They are mainly based on a kinematic chain of rigid blocks able to perform different “modes of damage” of structures subjected to horizontal actions. This paper presents an innovative methodology for testing; its aim is to identify a simplified model for out-of-plane response of rubbleworks with respect to the experimental evidence. The case study of L’Aquila district is discussed.

  8. Rubble masonry response under cyclic actions: The experience of L'Aquila city (Italy)

    Science.gov (United States)

    Fonti, Roberta; Barthel, Rainer; Formisano, Antonio; Borri, Antonio; Candela, Michele

    2015-12-01

    Several methods of analysis are available in engineering practice to study old masonry constructions. Two commonly used approaches in the field of seismic engineering are global and local analyses. Despite several years of research in this field, the various methodologies suffer from a lack of comprehensive experimental validation. This is mainly due to the difficulty in simulating the many different kinds of masonry and, accordingly, the non-linear response under horizontal actions. This issue can be addressed by examining the local response of isolated panels under monotonic and/or alternate actions. Different testing methodologies are commonly used to identify the local response of old masonry. These range from simplified pull-out tests to sophisticated in-plane monotonic tests. However, there is a lack of both knowledge and critical comparison between experimental validations and numerical simulations. This is mainly due to the difficulties in implementing irregular settings within both simplified and advanced numerical analyses. Similarly, the simulation of degradation effects within laboratory tests is difficult with respect to old masonry in-situ boundary conditions. Numerical models, particularly on rubble masonry, are commonly simplified. They are mainly based on a kinematic chain of rigid blocks able to perform different "modes of damage" of structures subjected to horizontal actions. This paper presents an innovative methodology for testing; its aim is to identify a simplified model for out-of-plane response of rubbleworks with respect to the experimental evidence. The case study of L'Aquila district is discussed.

  9. Recycled concrete aggregate in portland cement concrete.

    Science.gov (United States)

    2013-01-01

    Aggregates can be produced by crushing hydraulic cement concrete and are known as recycled concrete : aggregates (RCA). This report provides results from a New Jersey Department of Transportation study to identify : barriers to the use of RCA in new ...

  10. Characterization and influence of fine recycled aggregates on masonry mortars properties

    Directory of Open Access Journals (Sweden)

    Saiz-Martínez, P.

    2015-09-01

    Full Text Available This research aims to study mechanical behaviour and relevant properties of masonry mortars fabricated using fine recycled aggregate in different mixture proportions. Fine recycled aggregates samples originated from the ceramic and concrete recycling process and coming from two recycling plants of Madrid region have been used. Tests were performed using 1:3:0.5 volumetric cement-to-aggregate-to-water ratio. Standardized sand with fine recycled aggregate replacement percentages were: 10%, 15%, 25%, 35% and 45%. A continuous size distribution curve can be observed and the main crystalline phases determined have been quartz, calcite and gypsum. Compressive strength, shrinkage and bond strength tests revealed poorer performance of recycled mortars compared to the conventional mortars; however, specific values are within the limits established by the manufacturers and standards. This study shows that cement-based mortars prepared with volumetric ratio 1:3:0.5 may contain up to 45% of fine recycled aggregates, without their properties being affected and without presenting significant losses.Esta investigación estudia el comportamiento mecánico y las propiedades más relevantes de los morteros de albañilería fabricados usando arenas recicladas en diferentes proporciones. Muestras pertenecientes a la línea de reciclaje cerámica y de hormigón proceden de dos centrales de reciclaje de la Comunidad de Madrid. Los ensayos se realizaron con una dosificación 1:3:0,5. Los porcentajes de arena reciclada fueron: 10%, 15%, 25%, 35% y 45%. Se observa una línea granulométrica continua y las principales fases cristalinas encontradas son cuarzo, calcita y yeso. Los ensayos de resistencia a compresión, retracción y adherencia muestran un peor comportamiento en los morteros reciclados frente a los morteros elaborados con arena normalizada, aunque dentro de los límites establecidos por normativas y fabricantes. Se deduce que, los morteros de alba

  11. Concrete durability

    Directory of Open Access Journals (Sweden)

    Gaspar Tébar, Demetrio

    1991-03-01

    Full Text Available The evidence that the concrete is not a material for ever was noticed from the beginning of its industrial use. In the present work, the author describes the studies carried out during the last century and the early ages of the present one, mainly devoted to the study of the durability in sea water. At the present days, and in spite of the numerous papers published from then, the study of the concrete durability continues focusing the research priorities and economical resources of researchers and industries related with this material. Moreover, the new laboratory techniques are allowing to understand old problems and even to open again the discussion on reaction mechanisms which were believed to be completely understood. The article finalizes with a brief description of the numerous studies carried out at the Institute Eduardo Torroja on concrete durability, mainly those related with the resistance against gypsum attack (so abundant in our country land and against sea water attack.

    La realidad de que el hormigón no es un material eterno y es susceptible de sufrir ataques por agentes químicos, fue constatada desde el comienzo mismo de su uso industrial. En el presente trabajo el autor enumera los estudios realizados el siglo pasado y a comienzos del presente sobre la durabilidad del hormigón en agua de mar. En la actualidad y a pesar de los numerosos trabajos desarrollados desde entonces, el estudio de la durabilidad del hormigón sigue centrando la atención prioritaria y los recursos económicos de los investigadores e industrias relacionadas con este material. Además las nuevas técnicas de estudio están permitiendo comprender antiguos problemas e incluso reabrir la discusión sobre mecanismos de reacción que se creían completamente explicados. Finaliza el artículo con una descripción somera de los múltiples trabajos realizados en el Instituto Eduardo Torreja sobre la materia, en especial los estudios realizados sobre

  12. Damage propagation in a masonry arch subjected to slow cyclic and dynamic loadings

    Directory of Open Access Journals (Sweden)

    J. Toti

    2014-07-01

    Full Text Available In the present work, the damage propagation of a masonry arch induced by slow cyclic and dynamic loadings is studied. A two-dimensional model of the arch is proposed. A nonlocal damage-plastic constitutive law is adopted to reproduce the hysteretic characteristics of the masonry material, subjected to cyclic static loadings or to harmonic dynamic excitations. In particular, the adopted cohesive model is able to take into account different softening laws in tension and in compression, plastic strains, stiffness recovery and loss due to crack closure and reopening. The latter effect is an unavoidable feature for realistically reproducing hysteretic cycles. In the studied case, an inverse procedure is used to calibrate the model parameters. Then, nonlinear static and dynamic responses of the masonry arch are described together with damage propagation paths.

  13. Proposal of Design Formulae for Equivalent Elasticity of Masonry Structures Made with Bricks of Low Modulus

    Directory of Open Access Journals (Sweden)

    Muhammad Ridwan

    2017-01-01

    Full Text Available Bricks of low elastic modulus are occasionally used in some developing countries, such as Indonesia and India. Most of the previous research efforts focused on masonry structures built with bricks of considerably high elastic modulus. The objective of this study is to quantify the equivalent elastic modulus of lower-stiffness masonry structures, when the mortar has a higher modulus of elasticity than the bricks, by employing finite element (FE simulations and adopting the homogenization technique. The reported numerical simulations adopted the two-dimensional representative volume elements (RVEs using quadrilateral elements with four nodes. The equivalent elastic moduli of composite elements with various bricks and mortar were quantified. The numerically estimated equivalent elastic moduli from the FE simulations were verified using previously established test data. Hence, a new simplified formula for the calculation of the equivalent modulus of elasticity of such masonry structures is proposed in the present study.

  14. Corrosion resistant alloys for reinforced concrete [2007

    Science.gov (United States)

    2007-07-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for 4-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focused ...

  15. Corrosion resistant alloys for reinforced concrete [2009

    Science.gov (United States)

    2009-04-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for four-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focus...

  16. Chapter K: Progress in the Evaluation of Alkali-Aggregate Reaction in Concrete Construction in the Pacific Northwest, United States and Canada

    Science.gov (United States)

    Shrimer, Fred H.

    2005-01-01

    The supply of aggregates suitable for use in construction and maintenance of infrastructure in western North America is a continuing concern to the engineering and resources-management community. Steady population growth throughout the region has fueled demand for high-quality aggregates, in the face of rapid depletion of existing aggregate resources and slow and difficult permitting of new sources of traditional aggregate types. In addition to these challenges, the requirement for aggregates to meet various engineering standards continues to increase. In addition to their physical-mechanical properties, other performance characteristics of construction aggregates specifically depend on their mineralogy and texture. These properties can result in deleterious chemical reactions when aggregate is used in concrete mixes. When this chemical reaction-termed 'alkali-aggregate reaction' (AAR)-occurs, it can pose a major problem for concrete structures, reducing their service life and requiring expensive repair or even replacement of the concrete. AAR is thus to be avoided in order to promote the longevity of concrete structures and to ensure that public moneys invested in infrastructure are well spent. Because the AAR phenomenon is directly related to the mineral composition, texture, and petrogenesis of the rock particles that make up aggregates, an understanding of the relation between the geology and the performance of aggregates in concrete is important. In the Pacific Northwest, some aggregates have a moderate to high AAR potential, but many others have no or only a low AAR potential. Overall, AAR is not as widespread or serious a problem in the Pacific Northwest as in other regions of North America. The identification of reactive aggregates in the Pacific Northwest and the accurate prediction of their behavior in concrete continue to present challenges for the assessment and management of geologic resources to the owners and operators of pits and quarries and to the

  17. On the Numerical Modeling of Confined Masonry Structures for In-plane Earthquake Loads

    Directory of Open Access Journals (Sweden)

    Mircea Barnaure

    2015-07-01

    Full Text Available The seismic design of confined masonry structures involves the use of numerical models. As there are many parameters that influence the structural behavior, these models can be very complex and unsuitable for the current design purposes of practicing engineers. Simplified models could lead to reasonably accurate results, but caution should be given to the simplification assumptions. An analysis of various parameters considered in the numerical modeling of confined masonry structural walls is made. Conclusions regarding the influence of simplified procedures on the results are drawn.

  18. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  19. FUETAP concrete

    International Nuclear Information System (INIS)

    McDaniel, E.W.; Delzer, D.B.

    1988-01-01

    Cement-based waste forms have been used for several decades to immobilize low-level radioactive wastes. With the appropriate formulation for a given waste, the forms - whether as grout sheets placed in shale fractures deep underground, mixed with soil in a trench, or as monoliths in shallow-land burial - can be provided with the ability to immobilize various low-level radioactive components and with adequate compressive and tensile strength to ensure their durability for many years without cracking or disintegration. Because of the high activity inherent in high-level wastes, the incorporation of these wastes into cementitious forms can cause problems such as gas-pressure build-up from pore water radiolysis and expansion and subsequent cracking from the wastes' thermal activity, either of which can result in the release of radionuclides into the environment. This article discusses FUETAP concretes which utilize the thermal power of the waste to accelerate the curing process. If necessary, heat is also applied externally. In the end, a hard, dense product is obtained from which more than 98% of the unbound water has been driven off; the problems of radiolytic decomposition and thermal expansion become negligible

  20. Frequency Analysis of Acoustic Emission Signal to Monitor Damage Evolution in Masonry Structures

    International Nuclear Information System (INIS)

    Masera, D; Bocca, P; Grazzini, A

    2011-01-01

    A crucial aspect in damage evaluation of masonry structures is the analysis of long-term behaviour and for this reason fatigue analysis has a great influence on safety assessment of this structures. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced and unreinforced masonry walls under variable amplitude and static loading has been carried out. During these tests, the AE signals were recorded. The AE signals were analysed using Fast Fourier Transform (FFT) to examine the frequency distribution of the micro and macro cracking. It possible to evaluate the evolution of the wavelength of the AE signal through the two characteristic peak in the AE spectrum signals and the wave speed of the P or S waves. This wavelength evolution can be represent the microcrak and macrocrack evolution in masonry walls. This procedure permits to estimate the fracture dimension characteristic in several loading condition and for several masonry reinforced condition.

  1. Influence of masonry infill walls on longitudinal forces in columns of ...

    African Journals Online (AJOL)

    In this paper the result of conducted numerical studies based on space calculation models are presented. It presents the results of a conducted numerical assessment of the influence of masonry infill walls on variation and redistribution of efforts arising in columns of a cast-in-situ framed building. The quantitative data of the ...

  2. Damage functions for the vulnerability assessment of masonry buildings subjected to tunneling

    NARCIS (Netherlands)

    Giardina, C.; Hendriks, M.A.N.; Rots, J.G.

    2015-01-01

    This paper describes a new framework for the assessment of potential damage caused by tunneling-induced settlement to surface masonry buildings. Finite element models in two and three dimensions, validated through comparison with experimental results and field observations, are used to investigate

  3. Prototype of a diagnostic decision support tool for structural damage in masonry

    NARCIS (Netherlands)

    De Vent, I.A.E.

    2011-01-01

    This prototype of a diagnostic decision support tool for structural damage in traditional masonry is the result of a PhD research project. The research project has aimed to improve and facilitate the diagnostic process by offering support in the initial phase in which hypotheses are generated. The

  4. Collapse mechanisms and the existence of equilibrium solutions for masonry bodies

    Czech Academy of Sciences Publication Activity Database

    Šilhavý, Miroslav

    2014-01-01

    Roč. 19, č. 7 (2014), s. 821-831 ISSN 1081-2865 Institutional support: RVO:67985840 Keywords : equilibrium of masonry bodies * collapse mechanism * coercivity Subject RIV: BA - General Mathematics Impact factor: 1.298, year: 2014 http://mms.sagepub.com/content/19/7/821

  5. Large-scale testing program for the seismic characterization of Dutch masonry walls.

    NARCIS (Netherlands)

    Messali, F.; Ravenshorst, G.J.P.; Esposito, R.; Rots, J.G.

    2017-01-01

    The evaluation of the seismic response of unreinforced masonry buildings is a popular topic all over the world. In recent years, also the Netherlands started to face seismic risk, since the induced seismicity in the north of the country considerably increased (the gas extraction started in 1963, and

  6. Cyclic pushover test on an unreinforced masonry structure reseambling a typical Dutch terraced house

    NARCIS (Netherlands)

    Esposito, R.; Terwel, K.C.; Ravenshorst, G.J.P.; Schipper, H.R.; Messali, F.; Rots, J.G.

    2016-01-01

    During the last years, induced seismicity in the northern part of the Netherlands increased and the seismic assessment of unreinforced masonry (URM) structures became an important issue. As the problem is recent, the current building stock is not designed to withstand earthquakes and national

  7. Computational modeling of the cyclic pushover test on a calcium silicate element masonry assemblage

    NARCIS (Netherlands)

    Pari, M.; Jafari, S.; Messali, F.; Esposito, R.; Rots, J.G.; Quist, W.J.; Granneman, S.J.C.; van Hees, R.P.J.

    2017-01-01

    Induced seismicity in the Groningen region of the Netherlands has led to a large scale testing campaign on Calcium silicate element masonry structures at Delft University of Technology. An overview of the finite element analysis (FEA) using an implicit solver, on the full scale quasi-static cyclic

  8. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken

  9. Damages to masonry due to interaction(s) between mortar and brick

    NARCIS (Netherlands)

    Klugt, L.J.A.R. van der

    1995-01-01

    Masonry consists of brick and mortar. Next to the laying mortar there can be a separate pointing mortar as well. Each of these components can suffer damage. Such damages, of course, have to do with the properties of the components and with the agressiveness of the environment. However, next to their

  10. Collapse mechanisms and the existence of equilibrium solutions for masonry bodies

    Czech Academy of Sciences Publication Activity Database

    Šilhavý, Miroslav

    2014-01-01

    Roč. 19, č. 7 (2014), s. 821-831 ISSN 1081-2865 Institutional support: RVO:67985840 Keywords : equilibrium of masonry bodies * collapse mechanism * coercivity Subject RIV: BA - General Mathematics Impact factor: 1.298, year: 2014 http:// mms .sagepub.com/content/19/7/821

  11. Desalination of historic masonry : From pre-investigation to after-care

    NARCIS (Netherlands)

    Van Hees, R.P.J.; Lubelli, B.

    2010-01-01

    Salt crystallization constitutes one of the most widespread decay mechanisms affecting historic buildings. Desalination is a conservation treatment of growing importance in the case of historic masonry. This paper describes the approach from pre-investigation and treatment to follow-up care as the

  12. Determination of moisture content in masonry materials. Calibration of some direct methods

    NARCIS (Netherlands)

    Binda, L.; Squarcina, T.; Hees, R.P.J. van

    1996-01-01

    The presence of moisture in masonry wails is always a direct or indirect source of damace: the aesthetics of the building, the performance of the materials and the in-door hvgrothermic conditions can heavily change when the moisture content exceeds the normal hygroscopic value. The determination of

  13. Empirical studies of flexural strength for dry-stack Interlocking masonry

    African Journals Online (AJOL)

    Tests were carried out to establish the flexural strength of dry-stack masonry under vertical and horizontal bending. Two formats of wallettes were tested. Format 1 made of specimens constructed span normal to bed joints, which were tested under vertical bending and Format 2 specimens constructed span parallel to bed ...

  14. Update to UFC 3-340-02 for Blast Resistant Design of Masonry Components

    Science.gov (United States)

    2010-07-01

    resistance to cause fixity at the bottom of a reinforced masonry wall than granular soil. The resisting moment from cohesive soil in Figure 1 is calculated...Dowels cause fixity in unreinforced wall 14 14 Moment Restraint Provided by Foundation Clay Soil (Brom’s Method) Granular Soil (Rankine’s Method) 15 15

  15. Expert Meeting Report. Interior Insulation Retrofit of Mass Masonry Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Van Straaten, R. [Building Science Corporation, Somerville, MA (United States)

    2012-02-01

    The Building Science Consortium held an Expert Meeting on Interior Insulation Retrofit of Mass Masonry Wall Assemblies on July 30, 2011, at the Westford Regency Hotel in Westford, MA. This report outlines the extensive information that was presented on assessment of risk factors for premature building deterioration due to interior insulation retrofits, and methods to reduce such risks.

  16. Expert Meeting Report: Interior Insulation Retrofit of Mass Masonry Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Van Straaten, R.

    2012-02-01

    The Building Science Consortium held an Expert Meeting on Interior Insulation Retrofit of Mass Masonry Wall Assemblies on July 30, 2011 at the Westford Regency Hotel in Westford, MA. This report outlines the extensive information that was presented on assessment of risk factors for premature building deterioration due to interior insulation retrofits, and methods to reduce such risks.

  17. The evaluation of damage mechanism of unreinforced masonry buildings after Van (2011) and Elazig (2010) Earthquakes

    International Nuclear Information System (INIS)

    Güney, D; Aydin, E; Öztürk, B

    2015-01-01

    On March 8 th , 2010 Karakocan-Elazig earthquake of magnitude 6.0 occurred at a region where masonry and adobe construction is very common. Karakocan-Elazig is located in a high seismicity region on Eastern Anatolian Fault System (EAFS). Due to the earthquake, 42 people were killed and 14’113 buildings were damaged. Another city, Van located at South east of Turkey is hit by earthquakes with M = 7.2 occurred on October 23 rd , 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanli village) and M = 5.6 on November 9 th , 2011 with an epicenter near the town of Edremit, south of Van and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 10’000 buildings were seriously damaged. There are many traditional types of structures existing in the region hit by earthquakes (both Van and Elazig). These buildings were built as adobe, unreinforced masonry or mixed type. These types of buildings are very common in rural areas (especially south and east) of Turkey because of easy workmanship and cheap construction cost. Many of those traditional type structures experienced serious damages. The use of masonry is very common in some of the world's most hazard-prone regions, such as in Latin America, Africa, the Indian subcontinent and other parts of Asia, the Middle East, and southern Europe. Based on damage and failure mechanism of those buildings, the parameters affecting the seismic performance of those traditional buildings are analyzed in this paper. The foundation type, soil conditions, production method of the masonry blocks, construction method, the geometry of the masonry walls, workmanship quality, existence of wooden beams, type of roof, mortar between adobe blocks are studied in order to understand the reason of damage for these types of buildings. (paper)

  18. Tests and Analysis of the Compressive Performance of an Integrated Masonry Structure of a Brick-Stem-Insulating Layer

    Directory of Open Access Journals (Sweden)

    Suizi Jia

    2016-05-01

    Full Text Available This paper proposes, for low buildings, an integrated wall structure of a brick-stem-insulating layer, which plays a major part in both heat preservation and force bearing. The research team has tested the thermal performance of the structure, the results of which are satisfying. To further study the force-bearing performance, the paper carries out compressive tests of specimens of different structural design, with two types of bricks, i.e., clay and recycled concrete bricks; three types of stems, i.e., square-shaped wood, square-shaped steel pipe and circular steel pipe; and one type of insulating layer, i.e., fly ash masonry blocks. Afterward, the force bearing performance, damage that occurred, compressive deformation and ductility of all of the specimens are compared. On the sideline, the structure is applied in the construction of a pilot residence project, yielding favorable outcomes. The results indicate that in comparison with a brick wall with an insulating layer sandwiched in between, the integrated wall structure of bricks and fly ash blocks is a more preferable choice in terms of compressive performance and ductility. The integrated wall structure of brick-stem-fly ash blocks delivers much better performance to this end. Note that regarding the stem’s contribution to compressive strength, circular steel pipe is highest, followed by square-shaped steel pipe and then square-shaped wood. The compressive performance of the sandwiched blocks surpasses that of the two brick wall pieces combined by a large margin.

  19. Cellular Concrete Bricks with Recycled Expanded Polystyrene Aggregate

    Directory of Open Access Journals (Sweden)

    Juan Bosco Hernández-Zaragoza

    2013-01-01

    Full Text Available Cellular concrete bricks were obtained by using a lightweight mortar with recycled expanded polystyrene aggregate instead of sandy materials. After determining the block properties (absorption, compressive strength, and tensile stresses, it was found that this brick meets the requirements of the masonry standards used in Mexico. The obtained material is lighter than the commercial ones, which facilitates their rapid elaboration, quality control, and transportation. It is less permeable, which helps prevent moisture formation retaining its strength due to the greater adherence shown with dry polystyrene. It was more flexible, which makes it less vulnerable to cracking walls due to soil displacements. Furthermore, it is economical, because it uses recyclable material and has properties that prevent deterioration increasing its useful life. We recommend the use of the fully dry EP under a dry environment to obtain the best properties of brick.

  20. Microscopic examination of deteriorated concrete

    NARCIS (Netherlands)

    Nijland, T.G.; Larbi, J.A.

    2010-01-01

    Concrete petrography is the integrated microscopic and mesoscale (hand specimen size) investigation of hardened concrete, that can provide information on the composition of concrete, the original relationships between the concrete's various constituents, and any changes therein, whether as a result

  1. Sustainable Concrete Technology

    Directory of Open Access Journals (Sweden)

    Sim J.

    2015-12-01

    Full Text Available The growing concern over global warming and significant ecological changes requires sustainable development in all fields of science and technology. Concrete not only consumes huge amount of energy and natural sources, but also emits large amount of CO2, mainly due to the production of cement. It is evident that such large amount of concrete production has put significant impact on the energy, resource, environment, and ecology of the society. Hence, how to develop the concrete technology in a sustainable way has become a significant issue. In this paper, some of Korean researches for sustainable development of concrete are presented. These are sustainable strengthening for deteriorated concrete structure, sustainable reinforcement of new concrete structure, sustainable concrete using recycled aggregate and supplementary cementing materials and finally application of each technique to precast concrete.

  2. Concrete pavement joint deterioration.

    Science.gov (United States)

    2015-12-01

    Concrete pavements are an important part of our national infrastructure. In recent years the relatively small number of reported joints deteriorating prematurely in concrete pavements around Indiana has increased. Changes over the past 45 years in IN...

  3. Concrete aggregate durability study.

    Science.gov (United States)

    2009-06-01

    There are many factors that affect the durability of Portland cement concrete (PCC), including the mix design and the : materials used, the quality of construction, and the environment. Durability is not an intrinsic property of the concrete, but : i...

  4. The neutron physics of concrete reflectors

    International Nuclear Information System (INIS)

    Monahan, S.P.

    1995-01-01

    It has long been known that concrete reflection can be an important factor in determining the critical state of any fissile system, single unit or storage array. Since there can be a large variation in the chemical makeup of concrete, mass-limit reduction factors are necessarily conservative, and may lead to a very uneconomical storage arrangement. This study was undertaken to clarify the importance of the various concrete constituents and to determine some general guidance as to the magnitude of the reactivity effects for the more likely fissile material storage conditions

  5. Sampling and Analysis Instruction for the Demolition of the Masonry Block for the 108-F Biological Laboratory

    International Nuclear Information System (INIS)

    Byrnes, M. E.

    1999-01-01

    This sampling and analysis instruction (SAI) has been prepared to clearly define the sampling and analysis activities to be performed in support of the demolition and disposition (or disposal) of the 108-F Biological Laboratory masonry block walls

  6. concrete5 for developers

    CERN Document Server

    Uzayr, Sufyan bin

    2014-01-01

    Whether you have had some previous experience with concrete5 or are entirely new to it, this book will help you understand all that you need to know in order to get started with concrete5 development. A background in PHP is required; some knowledge of HTML/CSS is needed in order to fully grasp the concepts underlying concrete5 theme development.

  7. Deterioration of Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Chloride ingress is a common cause of deterioration of reinforced concrete bridges. Concrete may be exposed to chloride by seawater or de-icing salts. The chloride initiates corrosion of the reinforcement, which through expansion disrupts the concrete. In addition, the corrosion reduces the cross...

  8. Structures of masonry walls in buildings of permanent ruin – causes of damage and methods of repairs

    Directory of Open Access Journals (Sweden)

    Bartosz Szostak

    2017-12-01

    Full Text Available Currently there is a lot of castles classified as objects of the permanent ruin. In according to conservation doctrine, it is needed to protect this objects and prevent further degradation. Usually one of the most destructed element in this type of object is masonry wall. In this article has been described selected types of the masonry walls of the permanent ruin, causes of their damages and repairs methods.

  9. Nonlinear analyses and failure patterns of typical masonry school buildings in the epicentral zone of the 2016 Italian earthquakes

    Science.gov (United States)

    Clementi, Cristhian; Clementi, Francesco; Lenci, Stefano

    2017-11-01

    The paper discusses the behavior of typical masonry school buildings in the center of Italy built at the end of 1950s without any seismic guidelines. These structures have faced the recent Italian earthquakes in 2016 without diffuse damages. Global numerical models of the building have been built and masonry material has been simulated as nonlinear. Sensitivity analyses are done to evaluate the reliability of the structural models.

  10. A tool for the calculation of rockfall fragility curves for masonry buildings

    Science.gov (United States)

    Mavrouli, Olga

    2017-04-01

    Masonries are common structures in mountainous and coastal areas and they exhibit substantial vulnerability to rockfalls. For big rockfall events or precarious structures the damage is very high and the repair is not cost-effective. Nonetheless, for small or moderate rockfalls, the damage may vary in function of the characteristics of the impacting rock blocks and of the buildings. The evaluation of the expected damage for masonry buildings, and for different small and moderate rockfall scenarios, is useful for assessing the expected direct loss at constructed areas, and its implications for life safety. A tool for the calculation of fragility curves for masonry buildings which are impacted by rock blocks is presented. The fragility curves provide the probability of exceeding a given damage state (low, moderate and high) for increasing impact energies of the rock blocks on the walls. The damage states are defined according to a damage index equal to the percentage of the damaged area of a wall, as being proportional to the repair cost. Aleatoric and epistemic uncertainties are incorporated with respect to the (i) rock block velocity, (ii) rock block size, (iii) masonry width, and (iv) masonry resistance. The calculation of the fragility curves is applied using a Monte Carlo simulation. Given user-defined data for the average value of these four parameters and their variability, random scenarios are developed, the respective damage index is assessed for each scenario, and the probability of exceedance of each damage state is calculated. For the assessment of the damage index, a database developed by the results of 576 analytical simulations is used. The variables range is: wall width 0.4 - 1.0 m, wall tensile strength 0.1 - 0.6 MPa, rock velocity 1-20 m/s, rock size 1-20 m3. Nonetheless this tool permits the use of alternative databases, on the condition that they contain data that correlate the damage with the four aforementioned variables. The fragility curves can

  11. Ground Motion Characteristics of the 2015 Gorkha Earthquake, Survey of Damage to Stone Masonry Structures and Structural Field Tests

    Directory of Open Access Journals (Sweden)

    Rishi Ram Parajuli

    2015-11-01

    Full Text Available On April 25, 2015, a M7.8 earthquake rattled central Nepal; ground motion recorded in Kantipath, Kathmandu, 76.86 km east of the epicenter suggested that the low frequency component was dominant. We consider data from eight aftershocks following the Gorkha earthquake and analyze ground motion characteristics; we found that most of the ground motion records are dominated by low frequencies for events with a moment magnitude greater than 6. The Gorkha earthquake devastated hundreds of thousands of structures. In the countryside, and especially in rural mountainous areas, most of the buildings that collapsed were stone masonry constructions. Detailed damage assessments of stone masonry buildings in Harmi Gorkha had done, with an epicentral distance of about 17 km. Structures were categorized as large, medium and small depending on their plinth area size and number of stories. Most of the structures in the area were damaged; interestingly, all ridge-line structures were heavily damaged. Moreover, Schmidt hammer tests were undertaken to determine the compressive strength of stone masonry, brick masonry with mud mortar for normal buildings and historical monuments. The compressive strengths of stone and brick masonry were found to be 12.38 and 18.75 MPa, respectively. Historical structures constructed with special bricks had a compressive strength of 29.50 MPa. Pullout tests were also conducted to determine the stone masonry-mud mortar bond strength. The cohesive strength of mud mortar and the coefficient of friction were determined.

  12. Recycled Concrete as Aggregate for Structural Concrete Production

    OpenAIRE

    Mirjana Malešev; Vlastimir Radonjanin; Snežana Marinković

    2010-01-01

    A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC) as a control concrete and two types of concrete made with natural fine and recycle...

  13. Autogenous Deformation of Concrete

    DEFF Research Database (Denmark)

    Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions...... at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...

  14. DECISION ANALYSIS AND TECHNOLOGY ASSESSMENTS FOR METAL AND MASONRY DECONTAMINATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Ebadian, Ph.D.

    1999-01-01

    The purpose of this investigation was to conduct a comparative analysis of innovative technologies for the non-aggressive removal of coatings from metal and masonry surfaces and the aggressive removal of one-quarter to one-inch thickness of surface from structural masonry. The technologies tested should be capable of being used in nuclear facilities. Innovative decontamination technologies are being evaluated under standard, non-nuclear conditions at the FIU-HCET technology assessment site in Miami, Florida. This study is being performed to support the OST, the Deactivation and Decommissioning (D&D) Focus Area, and the environmental restoration of DOE facilities throughout the DOE complex by providing objective evaluations of currently available decontamination technologies.

  15. Comparison among different retrofitting strategies for the vulnerability reduction of masonry bell towers

    Science.gov (United States)

    Milani, Gabriele; Shehu, Rafael; Valente, Marco

    2017-11-01

    This paper investigates the effectiveness of reducing the seismic vulnerability of masonry towers by means of innovative and traditional strengthening techniques. The followed strategy for providing the optimal retrofitting for masonry towers subjected to seismic risk relies on preventing active failure mechanisms. These vulnerable mechanisms are pre-assigned failure patterns based on the crack patterns experienced during the past seismic events. An upper bound limit analysis strategy is found suitable to be applied for simplified tower models in their present state and the proposed retrofitted ones. Taking into consideration the variability of geometrical features and the uncertainty of the strengthening techniques, Monte Carlo simulations are implemented into the limit analysis. In this framework a wide range of idealized cases are covered by the conducted analyses. The retrofitting strategies aim to increase the shear strength and the overturning load carrying capacity in order to reduce vulnerability. This methodology gives the possibility to use different materials which can fulfill the structural implementability requirements.

  16. Internal Insulation of Masonry Walls with Wooden Floor Beams in Northern Humid Climate

    DEFF Research Database (Denmark)

    Morelli, Martin; Scheffler, Gregor Albrecht; Nielsen, Toke Rammer

    2010-01-01

    Multi-story buildings in Denmark from 1850–1950 are built with masonry walls and wooden floor beams. Large energy savings can be achieved by insulating the facades. Often interior insulation is the only possibility in order to keep the appearance of the external facade. The internal insulation...... reduces the drying potential of the wall, which might lead to moisture problems in the beam ends embedded in the masonry due to absorption of driving rain. This paper describes a solution to avoid the moisture problems and still achieve large energy savings. The thermal analyses are made in thermal...... depending on the amount of wind-driven rain hitting the facade. The proposed solution would almost halve the heat loss through a typical wall section compared to the original wall structure....

  17. Novel Predictive Model of the Debonding Strength for Masonry Members Retrofitted with FRP

    Directory of Open Access Journals (Sweden)

    Iman Mansouri

    2016-11-01

    Full Text Available Strengthening of masonry members using externally bonded (EB fiber-reinforced polymer (FRP composites has become a famous structural strengthening method over the past decade due to the popular advantages of FRP composites, including their high strength-to-weight ratio and excellent corrosion resistance. In this study, gene expression programming (GEP, as a novel tool, has been used to predict the debonding strength of retrofitted masonry members. The predictions of the new debonding resistance model, as well as several other models, are evaluated by comparing their estimates with experimental results of a large test database. The results indicate that the new model has the best efficiency among the models examined and represents an improvement to other models. The root mean square errors (RMSE of the best empirical Kashyap model in training and test data were, respectively, reduced by 51.7% and 41.3% using the GEP model in estimating debonding strength.

  18. DECISION ANALYSIS AND TECHNOLOGY ASSESSMENTS FOR METAL AND MASONRY DECONTAMINATION TECHNOLOGIES

    International Nuclear Information System (INIS)

    Ebadian, M.A.

    1999-01-01

    The purpose of this investigation was to conduct a comparative analysis of innovative technologies for the non-aggressive removal of coatings from metal and masonry surfaces and the aggressive removal of one-quarter to one-inch thickness of surface from structural masonry. The technologies tested should be capable of being used in nuclear facilities. Innovative decontamination technologies are being evaluated under standard, non-nuclear conditions at the FIU-HCET technology assessment site in Miami, Florida. This study is being performed to support the OST, the Deactivation and Decommissioning (D and D) Focus Area, and the environmental restoration of DOE facilities throughout the DOE complex by providing objective evaluations of currently available decontamination technologies

  19. Processor farming method for multi-scale analysis of masonry structures

    Science.gov (United States)

    Krejčí, Tomáš; Koudelka, Tomáš

    2017-07-01

    This paper describes a processor farming method for a coupled heat and moisture transport in masonry using a two-level approach. The motivation for the two-level description comes from difficulties connected with masonry structures, where the size of stone blocks is much larger than the size of mortar layers and very fine finite element mesh has to be used. The two-level approach is suitable for parallel computing because nearly all computations can be performed independently with little synchronization. This approach is called processor farming. The master processor is dealing with the macro-scale level - the structure and the slave processors are dealing with a homogenization procedure on the meso-scale level which is represented by an appropriate representative volume element.

  20. Study on the ratio and properties of the slurry of light insulation masonry with volcanic slag

    Science.gov (United States)

    Liguang, Xiao; Dawei, Jiang

    2017-12-01

    Volcanic slag is a kind of natural high quality porous material, and it has a good thermal insulation effect, and it is an extremely rich natural resource. Therefore, this paper adopts the natural volcanic slag as the aggregate to build the insulation mortar mix design for the slag masonry, and tests the related performance of the mortar. The results show that adopts natural volcanic slag as the aggregate and the cement use fly ash to replace, and the appropriate uniform sealing pores were introduced into the mortar mix. The performance of the manufactured products can meet the requirements of JC/T890. The coefficient of thermal conductivity of lightweight masonry mortar is less than 0.14W/(m•K), and the frost resistance is greater than 100 times, and it is with a low price.

  1. In Plan Shear Retrofit of Masonry Walls with Fibre Reinforced Polymer Composites Experimental Investigations

    Directory of Open Access Journals (Sweden)

    Tamás Nagy-György

    2006-01-01

    Full Text Available The paper presents the results from tests on clay brick masonry walls strengthened using fiber reinforced polymer (FRP composites. Five 1.50x1.50 m wall specimens have been subjected to pure in plan shear loads up to failure and then retrofitted on one side, with different types, percentages and lay-ups of the fiber sheets. Based on the experi¬mental results, it was proven the effectiveness of using externally bonded composites for retrofitting brick masonry walls, with less disruption during strengthening, and in this way with reduced costs compared with other conventional repairing and strengthening tech¬niques. Performances of the different strengthening configurations were compared in terms of ultimate load, strain in composite and failure mechanism.

  2. Seismic performance evaluation of multi-span existing masonry arch bridge

    Science.gov (United States)

    Laterza, Michelangelo; D'Amato, Michele; Casamassima, Vito Michele

    2017-07-01

    Existing old masonry arch bridges represent an architectural and cultural heritage of inestimable value, assuming nowadays an important strategic role since most of them are still in service and link roads of primary importance for vehicular traffic. They were mostly built in the last century without considering any horizontal action, and nowadays are serving roads characterized by a transit loads certainly heavier and more frequent than the ones of past. Moreover, very often due to absence of maintenance and to weathering conditions, the elements deteriorate more and more with a consequent loss of integrity and reduction of their carrying capacity. In this paper the seismic assessment of an old multi span masonry arch bridge still in service is illustrated. Pushover analyses are performed with the aim to investigate the numerical model sensitivity and the influence on the global nonlinear response of the bridge components.

  3. Utilización del software ArcoTSAM para el aprendizaje del comportamiento de las estructuras de fábrica = Using ArcoTSAM software as a learning tool in behavior of masonry structures

    Directory of Open Access Journals (Sweden)

    Fernando Magdalena Layos

    2017-08-01

    Full Text Available El aprendizaje del comportamiento mecánico de las estructuras de fábrica presenta ciertas dificultades. El conocimiento que subyace al estudio de las estructuras está condicionado por el uso casi exclusivo en su construcción en los últimos cien años de hormigón armado y acero. Los modelos habitualmente utilizados para analizar estas tipologías de estructuras no son aplicables a las construcciones de fábrica. Por ello, al comenzar a estudiar las fábricas hay una dificultad inicial que consiste en reconocer que se trata de una tipología de estructura diferente, y que para su comprensión hay que valerse de herramientas distintas a las que se utilizan habitualmente en la práctica profesional contemporánea. El programa ArcoTSAM que se presenta en este trabajo ha sido realizado por profesores del actual departamento de Estructuras y Física de Edificación (DEFE, de la Escuela Técnica Superior de Arquitectura de Madrid (ETSAM y es una herramienta que permite el análisis de estructuras de fábrica consideradas como agregados de bloques rígidos. Se trata de varios conjuntos de bibliotecas escritas en el lenguaje de programación de Maple. En este trabajo se muestra cómo la herramienta ArcoTSAM puede utilizarse para facilitar el aprendizaje del comportamiento de las estructuras de fábrica en cursos de grado o de máster, además de servir como herramienta de investigación. Abstract The Learning of the behavior of masonry structures have some difficulties. The tools usually applied are based in the knowledge acquired in last hundred years in the use of reinforced concrete and steel in structures. This way of proceeding cannot be used in the study of masonry structures. For this reason, when the study of masonry structures begins, students use to have an initial difficulty that consist in recognizing that masonry is a different kind of structure with a different behavior and other tools are needed in order to understand them. Arco

  4. Concrete blocks. Analysis of UNE, ISO en standards and comparison with other international standards

    Directory of Open Access Journals (Sweden)

    Álvarez Alonso, Marina

    1990-12-01

    Full Text Available This paper attempts to describe the recently approved UNE standards through a systematic analysis of the main specifications therein contained and the values considered for each of them, as well as the drafts for ISO and EN concrete block standards. Furthermore, the study tries to place the set of ISO standards in the international environment through a comparative analysis against a representative sample of the standards prevailing in various geographical regions of the globe to determine the analogies and differences among them. PALABRAS CLAVE: albañilería, análisis de sistemas, bloque de hormigón, muros de fábrica, normativa KEY WORDS: masonry, system analysis, concrete blocks, masonry walls, standards

    En este trabajo se pretende describir la reciente aprobada normativa UNE, analizando sistemáticamente las principales prescripciones contempladas y los valores considerados para cada una de ellas, así como los proyectos de Norma ISO, y EN sobre bloques de hormigón. Asimismo se intenta situar la normativa UNE en al ámbito internacional, haciendo un análisis comparativo con una representación de Normas de distintas regiones geográficas del mundo, determinando sus analogías y diferencias.

  5. Numerical simulations of tests masonry walls from ceramic block using a detailed finite element model

    Directory of Open Access Journals (Sweden)

    V. Salajka

    2017-01-01

    Full Text Available This article deals with an analysis of the behaviour of brick ceramic walls. The behaviour of the walls was analysed experimentally in order to obtain their bearing capacity under static loading and their seismic resistance. Simultaneously, numerical simulations of the experiments were carried out in order to obtain additional information on the behaviour of masonry walls made of ceramic blocks. The results of the geometrically and materially nonlinear computations were compared to the results of the performed tests.

  6. Experimental evaluation of the structural behaviour of adobe masonry structural elements

    OpenAIRE

    Varum, H.; Costa, A.; Pereira, H.; Almeida, J.; Rodrigues, H.; Silveira, D.

    2007-01-01

    Rehabilitation and strengthening of existing adobe masonry constructions have been neglected during the last decades. In Aveiro, Portugal, many adobe buildings present an important level of structural damage and, in many cases, are even near to ruin, having the majority a high vulnerability to seismic actions. To face the lack of information concerning the mechanical properties and structural behaviour of adobe elements, it was developed an experimental campaign. The composition and mechanica...

  7. PIXE, PIGE and NMR study of the masonry of the pyramid of Cheops at Giza

    Energy Technology Data Exchange (ETDEWEB)

    Demortier, Guy E-mail: guy.demortier@fundp.ac.be

    2004-11-01

    The mystery of the construction of the great pyramids of Egypt could be elucidated by physico-chemical measurements on small pieces of the material. In this paper, we give several arguments against the present point of view of most Egyptologists who do not admit another method than hewn blocks. We give several pieces of evidence that the masonry was entirely built by a moulding procedure involving the use of ingredients that were all available in the region of Cairo.

  8. Recycling of waste spent catalyst in road construction and masonry blocks.

    Science.gov (United States)

    Taha, Ramzi; Al-Kamyani, Zahran; Al-Jabri, Khalifa; Baawain, Mahad; Al-Shamsi, Khalid

    2012-08-30

    Waste spent catalyst is generated in Oman as a result of the cracking process of petroleum oil in the Mina Al-Fahl and Sohar Refineries. The disposal of spent catalyst is of a major concern to oil refineries. Stabilized spent catalyst was evaluated for use in road construction as a whole replacement for crushed aggregates in the sub-base and base layers and as a partial replacement for Portland cement in masonry blocks manufacturing. Stabilization is necessary as the waste spent catalyst exists in a powder form and binders are needed to attain the necessary strength required to qualify its use in road construction. Raw spent catalyst was also blended with other virgin aggregates, as a sand or filler replacement, for use in road construction. Compaction, unconfined compressive strength and leaching tests were performed on the stabilized mixtures. For its use in masonry construction, blocks were tested for unconfined compressive strength at various curing periods. Results indicate that the spent catalyst has a promising potential for use in road construction and masonry blocks without causing any negative environmental impacts. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Seismic Response of Pure-Friction Base Isolated Masonry Building with Restricted Base-Sliding

    Directory of Open Access Journals (Sweden)

    M. Qamaruddin

    2007-12-01

    Full Text Available The earthquake response of pure-friction base isolated masonry building with restricted base sliding is presented in this paper. A clear smoothened surface is created at the plinth level of the building above the damp-proof course, and the superstructure rests at this level to slide freely, except for the frictional resistance and the rigid stopper. As the superstructure is free to slide at the plinth level, there will be a feeling to the occupants that it might slide more than the permissible relative displacement limit provided at the top of the substructure. This may create a fear among the occupants that the building may overturn. In view of this, a mathematical model was developed for masonry building with restricted base sliding system using rigid stopper. Feasible position of the stopper has been determined such that the seismic response of the structure is reduced considerably in comparison with that of corresponding fixed base structure. Investigation was also made to determine the seismic response of the buildings with varying time period, mass ratio, coefficient of friction and damping coefficient subjected to Koyna and five other pseudo earthquakes. The pseudo earthquakes were generated either by increasing or decreasing the ground acceleration and duration of the Koyna accelerogram. It turns out from the present study that the pure-friction isolated restricted base sliding system is effective in reducing the seismic force acting on the masonry building with low value of coefficient of friction.

  10. Seismic Retrofit Measures for Masonry Walls of Historical Buildings, from an Energy Saving Perspective

    Directory of Open Access Journals (Sweden)

    Mariangela De Vita

    2018-03-01

    Full Text Available The planning of energy saving and structural retrofit interventions on masonry buildings are usually two separate projects; combined interventions are rare. Solutions tackling both aspects can reduce total refurbishment costs and improve global building performance. However, heavy interventions on the envelope have to be carefully designed in order to improve both seismic and energy performance whilst mitigating environmental impact. National energy saving regulations are generally less strict for historical buildings, making this category of buildings very interesting not only because of their widespread diffusion across Italy but also because of the possibility of planning interventions that will allow significant improvements by combining building efficiency and safety. This research looks at these aspects and proposes new methods for refurbishing masonry buildings combining seismic improvements and energy saving interventions. Among those mostly commonly applied on masonry buildings in Italy, and described in this paper, are various combined retrofit interventions, and we report the results of these interventions on thermal transmittance reduction and global costs.

  11. Role of the masonry in paintings during a seismic event analyzed by infrared vision

    Science.gov (United States)

    López, F.; Sfarra, S.; Ibarra-Castanedo, C.; Ambrosini, D.; Maldague, X. P. V.

    2015-06-01

    In this work, pulsed phase thermography (PPT), principal component thermography (PCT), and partial least squares thermography (PLST) techniques were applied in order to detect the masonry texture, as well as to map the subsurface damages formed beneath three different mural paintings. The latter were inspected after the 2009 earthquake, i.e., the seismic event that devastated L'Aquila City (Italy) and its surroundings. The mural supports explored by infrared thermography (IRT) are constituted by a single leaf, and the sides of the inspected paintings are confined by marble frames or by buried horizontal and vertical structures. Hence, the analyzed objects can be considered as monolithic structures. IRT can help to understand the masonry morphology, e.g. if there exist structural continuity between the arriccio layer (the first coat of plaster) and the support. In the present case, the heating phase was provided by lamps or propane gas and feature detection was enhanced by advanced signal processing. A comparison among the results is presented. Two of the three objects analyzed, painted by the art masters Serbucci and Avicola, are preserved inside Santa Maria della Croce di Roio Church in Roio Poggio (L'Aquila, Italy); they were executed on two masonries built in different periods. The last one was realized in Montorio al Vomano (Teramo, Italy) on the internal cloister of the Zoccolanti's Church (undated). The villages are separated by 50 km as the crow flies. Finally, near-infrared reflectography (NIRR) technique was also used to investigate the condition of the painting layer.

  12. Analysis of hydrogen generation according to the specific concrete composition during severe accident

    International Nuclear Information System (INIS)

    Seo, M. R.; Kim, M. K.

    2001-01-01

    The chemical composition of reactor cavity floor concrete affects the kind and amout of gases generated by MCCI and ablation of concrete. And if affects the physical and chemical characteristics of molten pool formed in the cavity. So, the specific concrete compostion is inputted in the MAAP Code used in the Level 2 PSA. and since Ulchin Unit 3 and 4 PSA, the analysis of concrete composition has been performed by the concrete mold prepared for this usage at the installation of cavity floor concrete. But, the composition of domestic concrete for construction of NPP is nearly the same as that of the standard basaltic concrete, and the effect of minor variation in composition is expected to be negligible. This report analyze the effect of the concrete composition to the generation of hydrogen due to MCCI, and discuss the necessity of analysis about the specific concrete composition for Level 2 PSA

  13. 枠組組積造壁の水平力抵抗機構から推察される無補強組積造建築の高耐震化技術

    OpenAIRE

    真田, 靖士; 中村, 友紀子; 山内, 成人; 雀, Ho; 中埜, 良昭; Sanada, Yasushi; Nakamura, Yukiko; Yamauchi, Naruhito; Choi, Ho; Nakano, Yoshiaki

    2006-01-01

    This paper mainly discusses seismic performances of specially designed unreinforced masonry (URM) structures. Firstly, lateral force resisting mechanisms of masonry in filled frames were introduced through test results of concrete block in filled reinforced concrete frames with and without a door opening. Based on major findings from the tests, a method to enhance seismic performances of URM structures using interlocking masonry units was proposed. Two new URM walls consisting of brittle and ...

  14. Carbonation and CO2 uptake of concrete

    International Nuclear Information System (INIS)

    Yang, Keun-Hyeok; Seo, Eun-A; Tae, Sung-Ho

    2014-01-01

    This study developed a reliable procedure to assess the carbon dioxide (CO 2 ) uptake of concrete by carbonation during the service life of a structure and by the recycling of concrete after demolition. To generalize the amount of absorbable CO 2 per unit volume of concrete, the molar concentration of carbonatable constituents in hardened cement paste was simplified as a function of the unit content of cement, and the degree of hydration of the cement paste was formulated as a function of the water-to-cement ratio. The contribution of the relative humidity, type of finishing material for the concrete surface, and the substitution level of supplementary cementitious materials to the CO 2 diffusion coefficient in concrete was reflected using various correction factors. The following parameters varying with the recycling scenario were also considered: the carbonatable surface area of concrete crusher-runs and underground phenomena of the decreased CO 2 diffusion coefficient and increased CO 2 concentration. Based on the developed procedure, a case study was conducted for an apartment building with a principal wall system and an office building with a Rahmen system, with the aim of examining the CO 2 uptake of each structural element under different exposure environments during the service life and recycling of the building. As input data necessary for the case study, data collected from actual surveys conducted in 2012 in South Korea were used, which included data on the surrounding environments, lifecycle inventory database, life expectancy of structures, and recycling activity scenario. Ultimately, the CO 2 uptake of concrete during a 100-year lifecycle (life expectancy of 40 years and recycling span of 60 years) was estimated to be 15.5%–17% of the CO 2 emissions from concrete production, which roughly corresponds to 18%–21% of the CO 2 emissions from the production of ordinary Portland cement. - Highlights: • CO 2 uptake assessment approach owing to the

  15. Statistical analysis of electrical resistivity as a tool for estimating cement type of 12-year-old concrete specimens

    NARCIS (Netherlands)

    Polder, R.B.; Morales-Napoles, O.; Pacheco, J.

    2012-01-01

    Statistical tests on values of concrete resistivity can be used as a fast tool for estimating the cement type of old concrete. Electrical resistivity of concrete is a material property that describes the electrical resistance of concrete in a unit cell. Influences of binder type, water-to-binder

  16. Special protective concretes

    International Nuclear Information System (INIS)

    Bouniol, P.

    2001-01-01

    Concrete is the most convenient material when large-scale radiation protection is needed. Thus, special concretes for nuclear purposes are used in various facilities like reactors, reprocessing centers, storage sites, accelerators, hospitals with nuclear medicine equipment, food ionization centers etc.. The recent advances made in civil engineering for the improvement of concrete durability and compactness are for a large part transposable to protection concretes. This article presents the basic knowledge about protection concretes with the associated typological and technological aspects. A large part is devoted to the intrinsic properties of concretes and to their behaviour in irradiation and temperature conditions: 1 - definition and field of application of special protective concretes; 2 - evolution of concepts and technologies (durability of structures, techniques of formulation, new additives, market evolution); 3 - design of protective structures (preliminary study, radiation characteristics, thermal constraints, damping and dimensioning, mechanical criteria); 4 - formulation of special concretes (general principles, granulates, hydraulic binders, pulverulent additives, water/cement ratio, reference composition of some special concretes); 5 - properties of special concretes (damping and thermo-mechanical properties); 6 - induced-irradiation and temperature phenomena (activation, radiolysis, mineralogical transformations, drying, shrinking, creep, corrosion of reinforcement). (J.S.)

  17. Use of metallic fibers in concretes

    Directory of Open Access Journals (Sweden)

    Kherbache Souad

    2014-04-01

    Full Text Available The addition of a waste (fibers in construction materials, particularly, the concretes is a technique increasingly used, for several reasons, either ecological, or economic, or to improve some properties in a fresh or hardened state. In our work we studied the behavior of the concrete and the mortar containing metallic fibers resulting from the unit BCR which is in Bordj-Menaiel in Algeria (metallic fibers resulting from the rejection at the end of the domestic operation of silvering of the tools and which is stored in plastic bags which are preserved in metal containers. Our work consists to study the behavior of the concretes and the mortars containing these fibers of cement substitution. We noted that the use of these fibers in the concretes in substitution of cement decreases its of compressive strength and flexural strength but to 10% of waste these strength remain acceptable.

  18. Study of sticky rice-lime mortar technology for the restoration of historical masonry construction.

    Science.gov (United States)

    Yang, Fuwei; Zhang, Bingjian; Ma, Qinglin

    2010-06-15

    Replacing or repairing masonry mortar is usually necessary in the restoration of historical constructions, but the selection of a proper mortar is often problematic. An inappropriate choice can lead to failure of the restoration work, and perhaps even further damage. Thus, a thorough understanding of the original mortar technology and the fabrication of appropriate replacement materials are important research goals. Many kinds of materials have been used over the years in masonry mortars, and the technology has gradually evolved from the single-component mortar of ancient times to hybrid versions containing several ingredients. Beginning in 2450 BCE, lime was used as masonry mortar in Europe. In the Roman era, ground volcanic ash, brick powder, and ceramic chip were added to lime mortar, greatly improving performance. Because of its superior properties, the use of this hydraulic (that is, capable of setting underwater) mortar spread, and it was adopted throughout Europe and western Asia. Perhaps because of the absence of natural materials such as volcanic ash, hydraulic mortar technology was not developed in ancient China. However, a special inorganic-organic composite building material, sticky rice-lime mortar, was developed. This technology was extensively used in important buildings, such as tombs, in urban constructions, and even in water conservancy facilities. It may be the first widespread inorganic-organic composite mortar technology in China, or even in the world. In this Account, we discuss the origins, analysis, performance, and utility in historic preservation of sticky rice-lime mortar. Mortar samples from ancient constructions were analyzed by both chemical methods (including the iodine starch test and the acid attack experiment) and instrumental methods (including thermogravimetric differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy). These analytical results show that the ancient masonry

  19. EXPERIMENTAL AND THEORETICAL STUDIES OF THE STRESS-STRAIN STATE OF WOOD-CONCRETE AND WOOD-GYPSUM MASONRY

    Directory of Open Access Journals (Sweden)

    Likhacheva Svetlana Yur'evna

    2012-12-01

    The findings of the prototype testing include identification of the two areas of deformations: areas of elastic deformations and areas of intensive development of deformations. The first area of partial elastic deformations is characterized by the linear stress function, while the second area demonstrates that this relationship is nonlinear. Permanent deformations appear as of the startup of the loading process and disproportionate stress is demonstrated throughout the deformation process. However, in the first area (partial elastic deformations residual deformations are so small that this area is considered as the area of "the area of incomplete elasticity".

  20. Non-Ductile Behavior of Reinforced Concrete Frames With Masonry Infill Panels Subjected to In-Plane Loading

    National Research Council Canada - National Science Library

    Al-Chaar, Ghassan

    1998-01-01

    Lessons learned from earthquakes in the last 50 years have spurred changes in building seismic code requirements, making it necessary to determine the seismic vulnerability of old military structures...

  1. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  2. Fire Resistance of Geopolymer Concretes

    Science.gov (United States)

    2010-03-21

    and general appearance to Portland cement concrete. Geopolymer concrete has been proposed as an alternative to Portland cement concrete in...1 Project report – Grant FA23860814096, "Fire resistance of geopolymer concretes" – J. Provis, University of Melbourne 1. Background and...experimental program This project provided funding for us to carry out fire testing of geopolymer concrete specimens and associated laboratory

  3. Evaluation of recycled concrete as aggregate in new concrete pavements.

    Science.gov (United States)

    2014-04-01

    This study evaluated the use of recycled concrete as coarse aggregate in new concrete pavements. : Recycled concrete aggregate (RCA) produced from demolished pavements in three geographically dispersed locations in Washington state were used to perfo...

  4. Concrete portable handbook

    CERN Document Server

    Woodson, R Dodge

    2011-01-01

    Whether or not, you are on the job site or back in the office, this book will help you to avoid mistakes, code violations, and wasted time and money. The book's four part treatment begins with constituent materials followed by self contained parts on Concrete Properties, Processes, and Concrete Repair and Rehabilitation. Designed to be an ""all in one"" reference, the author includes a wealth information for the most popular types of testing. This includes: Analysis of Fresh Concrete; Testing Machines; Accelerated Testing Methods; Analysis of Hardened Concrete and Mortar; Core Sampl

  5. An evaluation of new inhibitors for rebar corrosion in concrete.

    Science.gov (United States)

    2003-01-01

    The corrosion of reinforcing steel in concrete is estimated to affect more than 50% of the 575,000 bridges in the United States. One approach to mitigating this problem is to use corrosion-inhibitive compounds admixed into the concrete paste. This st...

  6. Feasibility study of two-lift concrete paving : technical report.

    Science.gov (United States)

    2014-04-01

    Two-lift concrete paving (2LCP) involves placing two layers of concrete (wet-on-wet) instead of a single : homogeneous layer, as is typically done in the United States. 2LCP offers the opportunity to optimize the use of local : aggregates, recycled m...

  7. Danish Investigations on Silica Fume Concretes at Elevated Temperatures

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    1992-01-01

    Describes fire tests in which the increased risk of explosive spalling of concrete densified by silica fume was first discovered. Further results are discussed from tests to define appropriate limits of silica fume content and to develop a new concrete for slender column units. Observations...

  8. Experimental Analysis of Repaired Masonry Elements with Flax-FRCM and PBO-FRCM Composites Subjected to Axial Bending Loads

    Directory of Open Access Journals (Sweden)

    Oscar A. Cevallos

    2015-11-01

    Full Text Available In the construction industry, the use of natural fabrics as a reinforcement for cement-based composites has shown great potential. The use of these sustainable composites to provide strengthening or repair old masonry structures that exhibit structural problems mainly due to a poor tensile strength of the mortar/brick joints is revealed to be a promising area of research. One of the most significant load conditions affecting the mechanical response of masonry structures occurs when axial bending loads are applied on the resistant cross-section. In this study, three different types of masonry elements were built using clay bricks and a lime-based mortar. After 28 days, the samples were subjected to concentric and eccentric compressive loads. In order to produce significant bending effects, the compressive loads were applied with large eccentricity, and a sudden failure characterized the behavior of the unreinforced masonry (URM elements. The tested masonry specimens were repaired using fabric-reinforced cementitious matrix (FRCM composites produced using bi-directional flax and polyparaphenylene benzobisoxazole (PBO fabrics. The mechanical behavior of the URM and repaired samples was compared in terms of load-displacement and moment-curvature responses. Furthermore, the results achieved using flax-FRCM composites were compared with those of using PBO-FRCM composites.

  9. LIGHTWEIGHT CONCRETE BASED GRANSHLAK

    Directory of Open Access Journals (Sweden)

    NETESA M. I.

    2016-02-01

    Full Text Available Raising of problem. Concrete advisable to obtain a low strength with local secondary resources for recycling and reduce the environmental burden on the environment. But it is important to design such concrete compositions with a reduced flow of cement. It is known that the coefficient of efficiency of use of cement in the concrete of the heavy and B10 is less than about 0.5, which is almost two times smaller than in class B15 concrete and above. Even lower coefficient of efficiency in light concrete cement low strength. Therefore, it is important to find patterns determining the composition of lightweight concrete based on local-products industry with more efficient use of cement in them. Purpose.. Based on the analysis of earlier research results, including with the use of methods of mathematical planning of experiments to determine the concrete contents, which can provide the requirements for the underlying layers of the floor, the compressive strength of which should correspond to the class B5. It is important to provide the required strength at minimum flow of the cement, which is the most expensive and energy-intensive part of concrete. Conclusion. Analysis of the test results of control samples of concrete in 28-day-old, the following laws. The required tensile strength of concrete compressive strength of 7.0 MPa can be obtained in the test range when used in formulations as a filler as the Dnieper hydroelectric power station fly ash and tailings Krivoy Rog iron ore YuGOK. To ensure providing the required characteristic strength of the concrete in the underlying layers of the floor is advisable to use a nominal composition per cubic meter of concrete: cement 160 kg granshlaka Plant named after Petrovsky, 675 kg of fly ash Dnieper HPP 390 kg, 400 kg of sand, 230 liters of water. Thus, while ensuring rational grain composition components can obtain the desired strength lightweight concrete based granshlaka plant Petrovsky, using as fillers

  10. Mechanical properties of concrete containing a high volume of tire-rubber particles.

    Science.gov (United States)

    Khaloo, Ali R; Dehestani, M; Rahmatabadi, P

    2008-12-01

    Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire-rubber particles as aggregate in concrete is investigated in this study. Tire-rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 12.5%, 25%, 37.5%, and 50% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire-rubber concrete.

  11. The Service Life Evaluation for Concrete Structure of NPP

    International Nuclear Information System (INIS)

    Lee, Choon Min; Kim, Seong Soo; Bae, Sung Hwan; Sik, Yoon Eui

    2014-01-01

    Prolonged exposure to the marine environment degrades the durability of concrete and shortens the service life of concrete due to degradation factors such as chloride, carbonation, freezing and thawing, sulfate. Therefore, many country's organizations like the Korea Concrete Institute (KCI), the American Concrete Institute (ACI), the International Federation for Structural Concrete (FIB), the American Society for Testing and Material (ASTM) which recognized the seriousness of this deterioration proposed equation models to evaluate the service life for the concrete structures. As a result, this paper is to especially consider the service life evaluation using these equation models for concrete structure of NPP in Korea compared with 60 years as a design service life. The concrete durability evaluation for Shin-Hanul NPP units 1 and 2 is carried out by using typically proposed assessment models in domestic and foreign standard. It is confirmed that the service life of concrete durability for each of deterioration factors is significantly higher than 60 years as a design service life. As a result, the study of combined deterioration for the concrete structures of NPP in future is positively necessary and maintenance control through regular monitoring should be conducted to secure safety margin basis

  12. Utilization of crushed clay brick in cellular concrete production

    Directory of Open Access Journals (Sweden)

    Ali A. Aliabdo

    2014-03-01

    Full Text Available The main objective of this research program is to study the effect of using crushed clay brick as an alternative aggregate in aerated concrete. Two series of mixtures were designed to investigate the physico-mechanical properties and micro-structural analysis of autoclave aerated concrete and foamed concrete, respectively. In each series, natural sand was replaced with crushed clay brick aggregate. In both series results showed a significant reduction in unit weight, thermal conductivity and sound attenuation coefficient while porosity has increased. Improvement on compressive strength of autoclave aerated concrete was observed at a percentage of 25% and 50% replacement, while in foamed concrete compressive strength gradually decreased by increasing crushed clay brick aggregate content. A comparatively uniform distribution of pore in case of foamed concrete with natural sand was observed by scanning electron microscope, while the pores were connected mostly and irregularly for mixes containing a percentage higher than 25% clay brick aggregate.

  13. Radiographic testing of concrete

    International Nuclear Information System (INIS)

    Porter, James F.

    1997-01-01

    The increase in construction activity in the Philippines, reinforced concrete building is still a favorite among designers, because it is much cheaper to build and it requires qualified welders, etc. and extensive nondestructive testing and inspection of metals, welds and castings. Of all the techniques radiography is widely used for concrete

  14. concrete5 Beginner's Guide

    CERN Document Server

    Laubacher, Remo

    2011-01-01

    This book is part of Packt's Beginner's Guide series. You will be guided through the set up of a Concrete5 site with step-by-step practical examples. This book is ideal for developers who would like to build their first site with Concrete5. Some k

  15. Concrete-Design

    Directory of Open Access Journals (Sweden)

    Leczovics Péter

    2014-12-01

    Full Text Available Present paper introduces a new interpretation of concrete, demonstrating some extreme possibilities of this rigid material such as a design element. In the first part a brief overview of the previous achievements are shown. The second part of this paper focuses on the relationship between concrete and fashion.

  16. Concrete deck material properties.

    Science.gov (United States)

    2009-01-01

    The two-fold focus of this study was (a) to develop an understanding of the mechanisms responsible for causing : cracking in the concrete; and (b) to study the influence of the local materials on the performance of NYSDOTs HP : concrete mixture. R...

  17. Fracture Mechanics of Concrete

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Going back in the memory pipeline, it was M F Kaplan1 (in 1961) who tried to obtain the fracture toughness of concrete. It was observed ... of cracks. The next question is how to bring the size effect into codes of practice on the design of reinforced concrete structures, since large structures like dams, nuclear reactors, very tall.

  18. Fracture Mechanics of Concrete

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    This special issue of S¯adhan¯a is rightly dedicated to the fracture mechanics of concrete. In particular, the size effect is highlighted. As appropriately pointed out in the first inter- national conference on fracture mechanics of concrete structures, FraMCos-I, organized by Z P Ba˘zant, at Breckenridge, Colorado in 1992, ...

  19. Experience in concreting of foundation plate for turbine plant at the Krimea NPP

    International Nuclear Information System (INIS)

    Dvorkin, L.I.; Glaznev, M.N.; Khojna, Eh.K.; Yanishevskij, I.V.; Orlovskij, V.M.

    1987-01-01

    The composition of a concrete mixture and methods of concreting when constructing the foundation plate for the Crimea NPP turbo-unit are described. The nomogram developed for operative determination of the heat insulation thickness of the poured concrete is presented

  20. 77 FR 21620 - Notice of the Buy America Waiver Request for Vossloh 101-LV Concrete Ties

    Science.gov (United States)

    2012-04-10

    ... the Buy America Waiver Request for Vossloh 101-LV Concrete Ties AGENCY: Federal Railroad... concrete ties, which contain certain components not manufactured in the United States. In furtherance of... concrete ties. FRA has received this request from the four States for the following projects: (a) The...

  1. Electrokinetic decontamination of concrete

    International Nuclear Information System (INIS)

    Lomasney, H.L.; Yachmenev, V.

    1994-01-01

    Concrete structures which have been contaminated with uranium and other radioisotopes may be decontaminated using in-situ electrokinetic remediation. By placing an electrode cell on the concrete surface and using the concrete's rebar, a ground rod, or another surface cell as the counter electrode, the radioisotopes may be migrated from the concrete into this cell. The process is highly dependent upon the chemical parameters of the species involved; namely, the concrete, the contaminants, and the solubilizers used to mobilize the contaminants. In a preliminary study conducted at the K-25 Site of the Oak Ridge National Labs, an estimated removal of >40 percent of uranium has been observed for a short duration run. This removal occurred using traditional uranium solubilizers in contact with the contaminated surface

  2. An Experimental Investigation of Mechanical Properties in Clay Brick Masonry by Partial Replacement of Fine Aggregate with Clay Brick Waste

    Science.gov (United States)

    Kumavat, Hemraj Ramdas

    2016-09-01

    The compressive stress-strain behavior and mechanical properties of clay brick masonry and its constituents clay bricks and mortar, have been studied by several laboratory tests. Using linear regression analysis, a analytical model has been proposed for obtaining the stress-strain curves for masonry that can be used in the analysis and design procedures. The model requires only the compressive strengths of bricks and mortar as input data, which can be easily obtained experimentally. Development of analytical model from the obtained experimental results of Young's modulus and compressive strength. Simple relationships have been identified for obtaining the modulus of elasticity of bricks, mortar, and masonry from their corresponding compressive strengths. It was observed that the proposed analytical model clearly demonstrates a reasonably good prediction of the stress-strain curves when compared with the experimental curves.

  3. Pushover, Response Spectrum and Time History Analyses of Safe Rooms in a Poor Performance Masonry Building

    International Nuclear Information System (INIS)

    Mazloom, M.

    2008-01-01

    The idea of safe room has been developed for decreasing the earthquake casualties in masonry buildings. The information obtained from the previous ground motions occurring in seismic zones expresses the lack of enough safety of these buildings against earthquakes. For this reason, an attempt has been made to create some safe areas inside the existing masonry buildings, which are called safe rooms. The practical method for making these safe areas is to install some prefabricated steel frames in some parts of the existing structure. These frames do not carry any service loads before an earthquake. However, if a devastating earthquake happens and the load bearing walls of the building are destroyed, some parts of the floors, which are in the safe areas, will fall on the roof of the installed frames and the occupants who have sheltered there will survive. This paper presents the performance of these frames located in a destroying three storey masonry building with favorable conclusions. In fact, the experimental pushover diagram of the safe room located at the ground-floor level of this building is compared with the analytical results and it is concluded that pushover analysis is a good method for seismic performance evaluation of safe rooms. For time history analysis the 1940 El Centro, the 2003 Bam, and the 1990 Manjil earthquake records with the maximum peak accelerations of 0.35g were utilized. Also the design spectrum of Iranian Standard No. 2800-05 for the ground kind 2 is used for response spectrum analysis. The results of time history, response spectrum and pushover analyses show that the strength and displacement capacity of the steel frames are adequate to accommodate the distortions generated by seismic loads and aftershocks properly

  4. Smart bricks for strain sensing and crack detection in masonry structures

    Science.gov (United States)

    Downey, Austin; D'Alessandro, Antonella; Laflamme, Simon; Ubertini, Filippo

    2018-01-01

    The paper proposes the novel concept of smart bricks as a durable sensing solution for structural health monitoring of masonry structures. The term smart bricks denotes piezoresistive clay bricks with suitable electronics capable of outputting measurable changes in their electrical properties under changes in their state of strain. This feature can be exploited to evaluate stress at critical locations inside a masonry wall and to detect changes in loading paths associated with structural damage, for instance following an earthquake. Results from an experimental campaign show that normal clay bricks, fabricated in the laboratory with embedded electrodes made of a special steel for resisting the high baking temperature, exhibit a quite linear and repeatable piezoresistive behavior. That is a change in electrical resistance proportional to a change in axial strain. In order to be able to exploit this feature for strain sensing, high-resolution electronics are used with a biphasic DC measurement approach to eliminate any resistance drift due to material polarization. Then, an enhanced nanocomposite smart brick is proposed, where titania is mixed with clay before baking, in order to enhance the brick’s mechanical properties, improve its noise rejection, and increase its electrical conductivity. Titania was selected among other possible conductive nanofillers due to its resistance to high temperatures and its ability to improve the durability of construction materials while maintaining the aesthetic appearance of clay bricks. An application of smart bricks for crack detection in masonry walls is demonstrated by laboratory testing of a small-scale wall specimen under different loading conditions and controlled damage. Overall, it is demonstrated that a few strategically placed smart bricks enable monitoring of the state of strain within the wall and provide information that is capable of crack detection.

  5. Cooling performance evaluation of the concrete cask

    International Nuclear Information System (INIS)

    Maruoka, Kunio; Matsunaga, Kenichi; Abe, Ganji; Irino, Mitsuhiro; Arikawa, Hiroshi; Tamaki, Mitsuo

    2002-01-01

    The concrete cask storage system stores spent fuel by first sealing it within canisters and then containing such canisters inside a concrete cask. This report describes the results of a full-size model test performed to examine the heat dissipation characteristics of the concrete cask and to ascertain its ability to deal with elevated temperature. The specification to which a full-size concrete cask model was fabricated assumed an interim storage of 17x17UO 2 fuel that was burned in PWR, estimating the heating value of spent fuel containing canister to be approximately 20 kW apiece. The test, which actually covered canister heating values ranging from 10 kW to 30 kW per unit to allow for temperature variations likely to be experienced in actual operation, verified that the concrete cask member did not exceed temperature limits. Test condition anticipated highest air temperature inside the spent fuel storage facility to be 30degC and, with reference to existing standard, set temperature limits of 65degC or less for the main body of concrete and 90degC or less for the local part as criteria. Preliminary 3-D thermo hydrodynamic analysis done prior to the test indicated that the temperature of the local part of the concrete cask member would be below 90degC. It also confirmed that steel material used as the structural member of the canisters or concrete cask would remain around 200degC even in an area where it was highest, validating that the integrity of such material would pose no problem from the analytical point of view. Heat dissipation performance test conducted in steady state verified that the concrete cask was able to have a sufficient cooling capacity against per-canister heating values in the 10 kW to 30 kW range which had been chosen in anticipation of temperature variation thought to be encountered in actual service. Also, to examine the consequence of the concrete cask having lost its cooling ability, another heat dissipation test was carried out under

  6. Structural behaviour of masonry arch with no-horizontal springing settlement

    Directory of Open Access Journals (Sweden)

    P. Zampieri

    2018-01-01

    Full Text Available This paper presents a calculation procedure for assessing the structural integrity of a masonry arch with non-horizontal springing settlement. By applying the Principle of Virtual Work (PVW to the deformed arch system, the procedure proposed herein details the reaction forces and thrust lines for each step of imposed settlement of the support. The procedure can also be used estimate the final displacement that causes complete failure of arch structural capacity. The results of the analysis procedure were compared against those obtained by experimental testing so as to validate the proposed calculation method

  7. Carpentry and Masonry Career Ladders, AFSCs 552X0/552X1/55273.

    Science.gov (United States)

    1985-01-01

    DPAT 3 3 HQ SAC/DPAT 3 3 HiQ SAC/TTGT I 1 *HQ TAC/DPAT 3 3 HQ TAC/TTGT 1 1 HQ JJSAF/XOOTF 1 1 HQ USAF/ MPPT 1 1 11Q USAFE/DPAT 3 3 HQ USAFE/TTGT 1 I *HQ...remove loose stucco apply finish coat to stucco walls apply brown coat for stucco walls inspect plaster or stucco surfaces for damage install control ...Equipment Mechanic WG-5309-8 Cement Finisher WG-3602-8 Maintenance Masonry Worker WG-3603-8 Worker WG-4749-8 Pest Controller WG-5026-6 I Electrical Worker

  8. Seismic fragility analysis of the block masonry wall in nuclear power plants

    International Nuclear Information System (INIS)

    Wang, Z-L.; Pandey, M.D.; Xie, X-C.

    2014-01-01

    The evaluation of seismic fragility of a structure is an integral part in the Seismic Probabilistic Risk Analysis (SPRA). The block masonry wall, a commonly used barrier in nuclear power plants, is fairly vulnerable to failure under an earthquake. In practice, the seismic fragility of block walls is commonly evaluated using a simple deterministic approach called Conservative Deterministic Failure Margin (CDFM) method. This paper presents a more formal fragility analysis of a block wall based on rigorous probabilistic methods and the accuracy of the CDFM method is evaluated by comparison to the more rigorous FA method. (author)

  9. Concrete sample point: 304 Concretion Facility

    International Nuclear Information System (INIS)

    Rollison, M.D.

    1995-01-01

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis

  10. Concrete sample point: 304 Concretion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Rollison, M.D.

    1995-03-10

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis.

  11. Use of nonwoven geotextiles as interlayers in concrete pavement systems.

    Science.gov (United States)

    2009-05-01

    This document describes the potential use of nonwoven geotextile materials as interlayers in concrete pavement systems, particularly unbonded overlays, in the United States. It briefly discusses Germanys experience, availability and cost of nonwov...

  12. Prediction of thermal behavior of pervious concrete pavements in winter.

    Science.gov (United States)

    2017-05-15

    Because application of pervious concrete pavement (PCPs) has extended to cold-climate regions of the United States, the safety and : mobility of PCP installations during the winter season need to be maintained. Timely application of salt, anti-icing,...

  13. Electrokinetic decontamination of concrete

    International Nuclear Information System (INIS)

    Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

    1996-01-01

    ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers' health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE's Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building's concrete floors included ThO 2 and thorium oxalate. The nitric acid was found to facilitate Th extraction

  14. Performance of Waterless Concrete

    Science.gov (United States)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  15. 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)

  16. Monomaterial ecological buildings, with Mopatel® and Ecopierra® concrete

    Directory of Open Access Journals (Sweden)

    Livia Miron

    2013-09-01

    Full Text Available This paper presents a case study performed on a pilot building from Gainesti, Suceava county. The constructive system used is unique in that it employs a monomaterial, namely ecological concrete of type MOPATEL® or ECOPIERRA®. These types of concrete, created by eng. Petrache Teleman, possess international patents and have received awards in Brussels, but they are not yet used in Romania. These materials can be used integrally to make all the constructive elements of a building – load-bearing elements (floors, beams, pillars, walls as well as the secondary elements of a partly finished building, such as screeds or non-load-bearing masonry. The constructive system also uses ecological mortars which integrally ensure the interior and exterior finishing. The final result is a building practically made from a single type of material, in which the effect of thermal bridges is reduced to a maximum. The MOPATEL and ECOPIERRA types of concrete have a mechanical resistance similar to regular concrete, but they also have superior thermal insulation qualities (between 0.09 and 0.28 W/mK, they are permeable to the transfer of water vapours from the interior to the exterior of the building, and, in certain compositions, they can also be considered waterproof.

  17. Strength and deformability of hollow concrete blocks: correlation of block and cylindrical sample test results

    Directory of Open Access Journals (Sweden)

    C. S. Barbosa

    Full Text Available This paper deals with correlations among mechanical properties of hollow blocks and those of concrete used to make them. Concrete hollow blocks and test samples were moulded with plastic consistency concrete, to assure the same material in all cases, in three diferente levels of strength (nominally 10 N/mm², 20 N/mm² and 30 N/mm². The mechanical properties and structural behaviour in axial compression and tension tests were determined by standard tests in blocks and cylinders. Stress and strain analyses were made based on concrete’s modulus of elasticity obtained in the sample tests as well as on measured strain in the blocks’ face-shells and webs. A peculiar stress-strain analysis, based on the superposition of effects, provided an estimation of the block load capacity based on its deformations. In addition, a tentative method to preview the block deformability from the concrete mechanical properties is described and tested. This analysis is a part of a broader research that aims to support a detailed structural analysis of blocks, prisms and masonry constructions.

  18. Biodecontamination of concrete

    International Nuclear Information System (INIS)

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-01-01

    A novel technology for biologically decontaminating concrete is being jointly developed by scientists at the Idaho National Engineering Laboratory (INEL) and British Nuclear Fuels plc (BNFL). The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of concrete. Most radionuclide contamination of concrete is fixed in the outer few mm of the concrete surface. By capturing and controlling this natural process, a biological method of removing the surface of concrete to depths up to several mm is being developed. Three types of bacteria are known to be important in MID of concrete: nitrifying bacteria that produce nitric acid, sulfur oxidizing bacteria that produce sulfuric acid, and certain heterotrophic bacteria that produce organic acids. An investigation of natural environments demonstrated with scanning electron microscopy the presence of bacteria on concrete surfaces of a variety of structures, such as bridges and dams, where corrosion is evident. Enumeration of sulfur oxidizing and nitrifying bacteria revealed their presence and activity on structures to varying degrees in different environments. Under ideal conditions, Thiobacillus thiooxidans, a sulfur oxidizing bacteria, attached to and colonized the surface of concrete specimens. Over 1mm depth of material from a 10 cm x 10 cm square surface was removed in 68 days in the Thiobacillus treated specimen compared to a sterile control. Laboratory and field demonstrations are currently being conducted using experimental chambers designed to be mounted directly to concrete surfaces where radionuclide contamination exists. Data is being obtained in order to determine actual rates of surface removal and limitations to the system. This information will be used to develop a full scale decontamination technology

  19. Numerical test for single concrete armour layer on breakwaters

    OpenAIRE

    Anastasaki, E; Latham, J-P; Xiang, J

    2016-01-01

    The ability of concrete armour units for breakwaters to interlock and form an integral single layer is important for withstanding severe wave conditions. In reality, displacements take place under wave loading, whether they are small and insignificant or large and representing serious structural damage. In this work, a code that combines finite- and discrete-element methods which can simulate motion and interaction among units was used to conduct a numerical investigation. Various concrete ar...

  20. concrete5 cookbook

    CERN Document Server

    Strack, David

    2013-01-01

    The Cookbook-style recipes allow you to go both directly to your topic of interest or follow topics throughout a chapter to gain in-depth knowledge. This practical Cookbook will cater to the needs of both intermediate and advanced concrete5 developers.This book is geared towards intermediate to advanced PHP developers who would like to learn more about the concrete5 content management system. Developers already familiar with concrete5 will learn new time-saving tricks and will find the book to be a great reference tool.

  1. Properties of high-workability concrete with recycled concrete aggregate

    OpenAIRE

    Safiuddin,; Alengaram,Ubagaram Johnson; Salam,Abdus; Jumaat,Mohd Zamin; Jaafar,Fahrol Fadhli; Saad,Hawa Binti

    2011-01-01

    This study presents the effects of recycled concrete aggregate (RCA) on the key fresh and hardened properties of concrete. RCA was used to produce high-workability concrete substituting 0-100% natural coarse aggregate (NCA) by weight. The slump and slump flow of fresh concretes were determined to ensure high workability. In addition, the compressive, flexural and splitting tensile strengths, modulus of elasticity, and permeable voids of hardened concretes were determined. The test results rev...

  2. Electrokinetic Strength Enhancement of Concrete

    Science.gov (United States)

    Cardenas, Henry E. (Inventor)

    2016-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  3. Electrokenitic Corrosion Treatment of Concrete

    Science.gov (United States)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  4. A historical examination of concrete

    International Nuclear Information System (INIS)

    Mallinson, L.G.; Li Davies, I.

    1987-01-01

    The requirement that concrete in radioactive waste repositories be stable physically and chemically for very long times has initiated studies of ancient and old concretes. This report is a contribution to this effort. After a description of the history of cement and concrete, the published literature relating to the analysis of old and ancient concrete is reviewed. A series of samples spanning the history of concrete has been obtained; a variety of physical and chemical techniques have been employed to characterize these samples. Reasons for survival of ancient concretes, and for durability of early, reinforced concretes are identified. Recommendations for further studies are given. 132 refs

  5. Analysis and optimization of the heat-insulating light concrete hollow brick walls design by the finite element method

    International Nuclear Information System (INIS)

    Coz Diaz, J.J. del; Garcia Nieto, P.J.; Betegon Biempica, C.; Prendes Gero, M.B.

    2007-01-01

    Department of Public Works, owners and building proprietors are demanding high-capacity heat-insulating exterior masonry components specifically for further energy savings. For housing and industrial structures there is also a great interest in light building materials with good physical material behaviour, with respect to an energy conscious and ecological design, which fulfils all strength and serviceability requirements. The major variables influencing the thermal conductivity of masonry materials are illustrated in this work by taking blocks made from no-fine lightweight concrete and different mortar properties. The finite element method (FEM) is used for finding accurate solutions of the heat transfer equation for five different light concrete hollow brick walls. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. The conduction and convection phenomena are taking into account in this study for three different values of the mortar conductivity and three different values for the bricks. Optimization of the walls is carried out from the finite element analysis of five hollow brick geometries by means of the mass overall thermal efficiency and the equivalent thermal conductivity. Finally, conclusions of this work are exposed

  6. Analysis and optimization of the heat-insulating light concrete hollow brick walls design by the finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Coz Diaz, J.J. del; Betegon Biempica, C.; Prendes Gero, M.B. [Edificio Departamental Viesques, No 7, 33204 Gijon (Asturias) (Spain); Garcia Nieto, P.J. [Departamento de Matematicas, Facultad de Ciencias, C/Calvo Sotelo s/n, 33007 Oviedo (Asturias) (Spain)

    2007-06-15

    Department of Public Works, owners and building proprietors are demanding high-capacity heat-insulating exterior masonry components specifically for further energy savings. For housing and industrial structures there is also a great interest in light building materials with good physical material behaviour, with respect to an energy conscious and ecological design, which fulfils all strength and serviceability requirements. The major variables influencing the thermal conductivity of masonry materials are illustrated in this work by taking blocks made from no-fine lightweight concrete and different mortar properties. The finite element method (FEM) is used for finding accurate solutions of the heat transfer equation for five different light concrete hollow brick walls. Mathematically, the non-linearity is due to the radiation boundary condition inside the inner recesses of the bricks. The conduction and convection phenomena are taking into account in this study for three different values of the mortar conductivity and three different values for the bricks. Optimization of the walls is carried out from the finite element analysis of five hollow brick geometries by means of the mass overall thermal efficiency and the equivalent thermal conductivity. Finally, conclusions of this work are exposed. (author)

  7. Experimental Characteristics of Dry Stack Masonry under Compression and Shear Loading.

    Science.gov (United States)

    Lin, Kun; Totoev, Yuri Zarevich; Liu, Hongjun; Wei, Chunli

    2015-12-12

    The behavior of dry stack masonry (DSM) is influenced by the interaction of the infill with the frame (especially the joints between bricks), which requires further research. This study investigates the compression and shear behaviors of DSM. First, a series of compression tests were carried out on both masonry prism with mortar (MP_m) and DSM prism (MP_ds). The failure mode of each prism was determined. Different from the MP_m, the stress-strain relationship of the MP_ds was characterized by an upward concavity at the initial stage. The compression strength of the MP_ds was slightly reduced by 15%, while the elastic modulus was reduced by over 62%. In addition, 36 shear-compression tests were carried out under cyclic loads to emphasize the influence of various loads on the shear-compression behavior of DSM. The results showed that the Mohr-Coulomb friction law adequately represents the failure of dry joints at moderate stress levels, and the varying friction coefficients under different load amplitudes cannot be neglected. The experimental setup and results are valuable for further research.

  8. Evaluation of the behavior of brick tile masonry and mortar due to capillary rise of moisture

    Directory of Open Access Journals (Sweden)

    Camino, M. S.

    2014-06-01

    Full Text Available For a better understanding of the behaviour of old brick masonry in facing the rising damp problem, multiple tests were made in the laboratory: water absorption, moisture content, apparent porosity, temperature and thermal camera imaging on brick masonry and its components: brick and mortar. This has allowed us to determine which of the previous tests is the best in predicting the behaviour of a real wall. In addition, the tests have also helped in defining a process to evaluate the moisture content of walls in a buildings, which is important for heritage restoration projects.Para un mejor conocimiento del comportamiento de las fábricas antiguas de ladrillo frente a la ascensión capilar de agua, se han realizado en laboratorio ensayos de absorción de agua, de contenido de humedad, de porosidad aparente, de temperatura e imágenes con cámara termográfica sobre muros de fábrica y sus materiales componentes: ladrillo y argamasa. Ello ha permitido inferir cuál es el ensayo realizado a los ladrillos que mejor predice el comportamiento del muro real. También ha permitido definir un procedimiento para evaluar el contenido de humedad de fábricas existentes, importante para los proyectos de restauración del patrimonio construido.

  9. Development of Interlocking Masonry Bricks and its’ Structural Behaviour: A Review Paper

    Science.gov (United States)

    Al-Fakih, Amin; Mohammed, Bashar S.; Nuruddin, Fadhil; Nikbakht, Ehsan

    2018-04-01

    Conventional bricks are the most elementary building materials for houses construction. However, the rapid growth in today’s construction industry has obliged the civil engineers in searching for a new building technique that may result in even greater economy, more efficient and durable as an alternative for the conventional brick. Moreover, the high demands for having a speedy and less labour and cost building systems is one of the factor that cause the changes of the masonry conventional systems. These changes have led to improved constructability, performance, and cost as well. Several interlocking bricks has been developed and implemented in building constructions and a number of researches had studied the manufacturing of interlocking brick and its structural behaviour as load bearing and non-load bearing element. This technical paper aims to review the development of interlocking brick and its structural behaviour. In conclusion, the concept of interlocking system has been widely used as a replacement of the conventional system where it has been utilized either as load bearing or non-load bearing masonry system.

  10. Ethical Guidelines for Structural Interventions to Small-Scale Historic Stone Masonry Buildings.

    Science.gov (United States)

    Hurol, Yonca; Yüceer, Hülya; Başarır, Hacer

    2015-12-01

    Structural interventions to historic stone masonry buildings require that both structural and heritage values be considered simultaneously. The absence of one of these value systems in implementation can be regarded as an unethical professional action. The research objective of this article is to prepare a guideline for ensuring ethical structural interventions to small-scale stone historic masonry buildings in the conservation areas of Northern Cyprus. The methodology covers an analysis of internationally accepted conservation documents and national laws related to the conservation of historic buildings, an analysis of building codes, especially Turkish building codes, which have been used in Northern Cyprus, and an analysis of the structural interventions introduced to a significant historic building in a semi-intact state in the walled city of Famagusta. This guideline covers issues related to whether buildings are intact or ruined, the presence of earthquake risk, the types of structural decisions in an architectural conservation project, and the values to consider during the decision making phase.

  11. Masonry fireplace emissions test method: Repeatability and sensitivity to fueling protocol.

    Science.gov (United States)

    Stern, C H; Jaasma, D R; Champion, M R

    1993-03-01

    A test method for masonry fireplaces has been evaluated during testing on six masonry fireplace configurations. The method determines carbon monoxide and particulate matter emission rates (g/h) and factors (g/kg) and does not require weighing of the appliance to determine the timing of fuel loading.The intralaboratory repeatability of the test method has been determined from multiple tests on the six fireplaces. For the tested fireplaces, the ratio of the highest to lowest measured PM rate averaged 1.17 and in no case was greater than 1.32. The data suggest that some of the variation is due to differences in fuel properties.The influence of fueling protocol on emissions has also been studied. A modified fueling protocol, tested in large and small fireplaces, reduced CO and PM emission factors by roughly 40% and reduced CO and PM rates from 0 to 30%. For both of these fireplaces, emission rates were less sensitive to fueling protocol than emission factors.

  12. Low cost rubber seismic isolators for masonry housing in developing countries

    Science.gov (United States)

    Habieb, A. B.; Milani, G.; Tavio, Milani, F.

    2017-11-01

    Rubber isolators are used widely in constructions which require a vibration or seismic isolation. It consists of rubber layers and reinforcements that can be steel or fiber lamina. The fiber reinforced isolator results in a lower cost of production and application than that of steel. Using fiber reinforced isolator allows us to make an unbonded model of rubber bearing. This model leads to a smaller horizontal stiffness and larger displacement of isolators. Researchers consider the Unbonded Fiber Reinforced Elastomeric Isolator (U-FREI) as a low-cost form of rubber bearings. U-FREIs are suitable to isolate seismically a masonry building, which is a common type of housing in developing countries. In this work, we present a finite element model (FEM) to predict the behavior of the U-FREIs undergoing moderate deformations. We adopt a Yeoh hyperelasticity model which is available in the standard package of Abaqus FE software and estimate its coefficients through the available experimental data. Then, we apply that isolation system onto masonry housing with some simplified methods. We also observe the horizontal behaviors of U-FREIs under different vertical loads and consider a critical condition when the isolators start to be unstable. In parallel, we perform an analytical model to predict the shear behavior and the deformation limit of isolators. Finally, the results show that the analytical model is sufficiently accurate compared to the FE analyses.

  13. SSI on the Dynamic Behaviour of a Historical Masonry Building: Experimental versus Numerical Results

    Directory of Open Access Journals (Sweden)

    Francesca Ceroni

    2014-11-01

    Full Text Available A reliable procedure to identify the dynamic behaviour of existing masonry buildings is described in the paper, referring to a representative case study: a historical masonry palace located in Benevento (Italy. Since the building has been equipped with a permanent dynamic monitoring system by the Department of Civil Protection, some of the recorded data, acquired in various operating conditions, have been analysed with basic instruments of the Operational Modal Analysis in order to identify the main eigenfrequencies and vibration modes of the structure. The obtained experimental results have been compared to the numerical outcomes provided by three detailed Finite Element (FE models of the building. The influence of Soil-Structure Interaction (SSI has been also introduced in the FE model by a sub-structure approach where concentrated springs were placed at the base of the building to simulate the effect of soil and foundation on the global dynamic behaviour of the structure. The obtained results evidence that subsoil cannot a priori be disregarded in identifying the dynamic response of the building.

  14. Concrete decontamination and demolition methods

    International Nuclear Information System (INIS)

    LaGuardia, T.S.

    1980-01-01

    The US Department of Energy (DOE), Division of Environmental Control Technology, requested Nuclear Energy Services to prepare a handbook for the decontamination and decommissioning (D and D) of DOE-owned and commercially-owned radioactive facilities. the objective of the handbook is to provide the nuclear industry with guidance on the state-of-the-art methods and equipment available for decommissioning and to provide the means to estimate decommissioning costs and environmental impact. The methods available for concrete decontamination and demolition are summarized to provide an overview of some of the state-of-the-art techniques to be discussed at this workshop. The pertinent information on each method will include the selection factors such as the rate of performance in terms of concrete removal per unit time (cubic yards per day), manpower required by craft, unit cost (dollars per cubic yard) and the advantages and disadvantages. The methods included in this overview are those that have been routinely used in nuclear and nonnuclear applications or demonstrated in field tests. These methods include controlled blasting, wrecking ball or slab, backhoe mounted ram, flame torch, thermic lance, rock splitter, demolition compound, sawing, core stitch drilling, explosive cutting, paving breaker and power chisel, drill and spall, scarifying, water cannon and grinding

  15. INORGANIC CEMENT CONCRETE

    Directory of Open Access Journals (Sweden)

    Alisson Clay Rios Silva

    2014-07-01

    Full Text Available In this work, a Geopolymeric Cement Concrete (GCC was developed through adequate portions of geopolymer components. Its characteristics were compared with Portland Cement Concrete (PCC, through of the establishment of some parameters of design, as consumption of binders, water/aggregates ratio and mortar content. The concrete mechanical performance was evaluated with emphasis to the fatigue behavior. Were tested the effects of different tensile strength maximum (increasing and decreasing. The results of fatigue tests had shown that GCC presents a better performance when compared to PCC. Its fatigue strength was 15% higher than that of PCC, when 70% of rupture tension of the concrete in static bending (SR, was applied. Tensions of about 80% SR resulted in 96% of increase, when compared to GCC. The SEM microstructural analysis showed that the GCC has a matrix/aggregate bonding very strong, when compared to PCC, probably due to the massive nature of the geopolymeric matrix.

  16. Anchorage in concrete construction

    CERN Document Server

    Eligehausen, Rolf; Silva, John F

    2013-01-01

    A comprehensive treatment of current fastening technology using inserts (anchor channels, headed stud), anchors (metal expansion anchor, undercut anchor, bonded anchor, concrete screw and plastic anchor) as well as power actuated fasteners in concrete. It describes in detail the fastening elements as well as their effects and load-bearing capacities in cracked and non-cracked concrete. It further focuses on corrosion behaviour, fire resistance and characteristics with earthquakes and shocks. It finishes off with the design of fastenings according to the European Technical Approval Guideline (ETAG 001), the Final Draft of the CEN Technical Specification 'Design of fastenings for use in concrete' and the American Standards ACI 318-05, Appendix D and ACI 349-01, Appendix B.

  17. Concrete Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This is a 20,000-sq ft laboratory that supports research on all aspects of concrete and materials technology. The staff of this facility offer wide-ranging expertise...

  18. Improving concrete overlay construction.

    Science.gov (United States)

    2010-03-01

    Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for : construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, ...

  19. 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...

  20. Concrete decontamination scoping tests

    International Nuclear Information System (INIS)

    Archibald, K.E.

    1995-01-01

    This report details the research efforts and scoping tests performed at the Idaho Chemical Process Plant using scabbling, chemical, and electro-osmotic decontamination techniques on radiologically contaminated concrete

  1. Bituminous concrete overlay studies.

    Science.gov (United States)

    1971-01-01

    Deflection tests conducted on eight sections of primary highway, both before and after asphaltic concrete resurfacings, were analyzed as a study of the utility of such tests in the design of overlays. The application of tentative traffic and allowabl...

  2. Prestressed concrete design

    CERN Document Server

    Hurst, MK

    1998-01-01

    This edition provides up-to-date guidance on the detailed design of prestressed concrete structures. All major topics are dealt with, including prestressed flat slabs, an important and growing application in the design of buildings.

  3. Concrete decontamination by electro-hydraulic scabbling (EHS). Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    Contamination of concrete structures by radionuclides, hazardous metals and organic substances (including PCB`s) occurs at many DOE sites. The contamination of concrete structures (walls, floors, ceilings, etc.) varies in type, concentration, and especially depth of penetration into the concrete. In many instances, only the surface layer of concrete is contaminated, up to a depth of one inch, according to estimates provided in the R and D ID document. Then, removal of the concrete surface layer (scabbling) is considered to be the most effective decontamination method. Textron Systems Corp. (TSC) has developed a scabbling concept based on electro-mechanical phenomena accompanying strong electric pulses generated by applying high voltage at the concrete/water interface. Depending on the conditions, the electric discharge may occur either through a waste layer or through the concrete body itself. This report describes the development, testing, and results of this electro-mechanical process. Phase 1 demonstrated the feasibility of the process for the controlled removal of a thin layer of contaminated concrete. Phase 2 designed, fabricated, and tested an integrated subscale unit. This was tested at Fernald. In Phase 3, the scabbling unit was reconfigured to increase its power and processing rate. Technology transfer to an engineering contracting company is continuing.

  4. Recycling of concrete

    International Nuclear Information System (INIS)

    Halaszovich, S.

    1988-01-01

    The paper reviews potentials and problems of disposal or recycling of concrete removed from nuclear installations. Due to the difficulties in determining radioactivity limits that are compatible with utilization of recycled material in practice, a method is proposed that takes into account inhalation of dusts, as occurring during the reprocessing or recycling of the concrete, for instance in road building. This method is based on the maximum permissible radioactivity uptake by inhalation of a nuclide mixture of unknown composition. (RB) [de

  5. Sulfur polymer cement concrete

    International Nuclear Information System (INIS)

    Weber, H.H.; McBee, W.C.

    1990-01-01

    Sulfur-based composite materials formulated using sulfur polymer cement (SPC) and mineral aggregates are described and compared with conventional portland cement based materials. Materials characteristics presented include mechanical strength, chemical resistance, impact resistance, moisture permeation, and linear shrinkage during placement and curing. Examples of preparation and placement of sulfur polymer cement concrete (SC) are described using commercial scale equipment. SC applications presented are focused into hostile chemical environments where severe portland cement concrete (PCC) failure has occurred

  6. Concrete shaver. Innovative technology summary report

    International Nuclear Information System (INIS)

    1998-12-01

    The US Department of Energy (DOE) is in the process of decontamination and decommissioning (D and D) for many of its nuclear facilities throughout the United States. These facilities must be dismantled and the demolition waste sized into manageable pieces for handling and disposal. The facilities undergoing D and D are typically chemically and/or radiologically contaminated. To facilitate this work, DOE requires a tool capable of removing the surface of radiologically contaminated concrete floors. Operating requirements for the tool include simple and economical operation, the capability of operating in ambient temperatures from 3 C to 40 C (37 F to 104 F), and the ability to be easily decontaminated. The tool also must be safe for workers. The Marcrist Industries Limited concrete shaver is an electrically driven, self-propelled concrete and coating removal system. This technology consists of a 25-cm (10-in.)-wide diamond impregnated shaving drum powered by an electric motor and contains a vacuum port for dust extraction. The concrete shaver is ideal for use on open, flat, floor areas. The shaver may also be used on slightly curved surfaces. This shaver is self-propelled and produces a smooth, even surface with little vibration. The concrete shaver is an attractive alternative to traditional pneumatic scabbling tools, which were considered the baseline in this demonstration. The use of this tool reduces worker fatigue (compared to the baseline) due to lower vibration. The shaver is more than five times faster than the five-piston pneumatic scabbler at removing contamination from concrete. Because of this increased productivity, the shaver is 50% less costly to operate than baseline technologies. The DOE has successfully demonstrated the concrete shaver for decontaminating floors for free-release surveys prior to demolition work

  7. Shear Resistance between Concrete-Concrete Surfaces

    Science.gov (United States)

    Kovačovic, Marek

    2013-12-01

    The application of precast beams and cast-in-situ structural members cast at different times has been typical of bridges and buildings for many years. A load-bearing frame consists of a set of prestressed precast beams supported by columns and diaphragms joined with an additionally cast slab deck. This article is focused on the theoretical and experimental analyses of the shear resistance at an interface. The first part of the paper deals with the state-of-art knowledge of the composite behaviour of concrete-concrete structures and a comparison of the numerical methods introduced in the relevant standards. In the experimental part, a set of specimens with different interface treatments was tested until failure in order to predict the composite behaviour of coupled beams. The experimental part was compared to the numerical analysis performed by means of FEM basis nonlinear software.

  8. Fibre-concrete container

    International Nuclear Information System (INIS)

    2000-01-01

    In this leaflet the fibre-concrete container for radioactive wastes is described. The fibre container is made of fibre-concrete that contains cement, aggregate, sand, filter, flame-silica, super-plastificator, water and scattered metal fibres. The fibre-concrete container has a dice shape with outer dimension 1.7 x 1.7 x 1.7 m. It is mounted of a container body, a container cover and two caps. Total weight of container is 4,240 kg, maximum weight of loaded container do not must exceed 15,000 kg. The physical and mechanical properties of the fibre-concrete container are described in detail. The fibre-concrete container manufactured for storing of low and intermediate radioactive wastes. A fibre-concrete container utilization to store of radioactive wastes solves these problems: increase of stability of stored packages of radioactive waste; watertightness within 300 years at least; static stability of bearing space; better utilization of bearing spaces; insulation of radioactive waste in a case of seismic and geological event; increase of fire resistance; and transport of radioactive waste

  9. Performance of "Waterless Concrete"

    Science.gov (United States)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  10. Evaluation of the seismic response of historical masonry bell towers located in South-East Lombardy, Italy

    Science.gov (United States)

    Valente, Marco; Milani, Gabriele; Shehu, Rafael

    2017-07-01

    This study presents some FE results regarding the behavior under horizontal loads of two existing masonry towers located in South-East Lombardy, Italy. The towers, albeit unique for geometric and architectural features, show some affinities that justify a comparative analysis, as for instance the location and the similar masonry material. Their structural behavior under horizontal loads is therefore influenced by geometrical issues, such as slenderness, walls thickness, perforations, irregularities, presence of internal vaults, etc., which may be responsible for a peculiar output. The geometry of the towers is deduced from both existing available documentation and in-situ surveys. On the basis of such geometrical data, a detailed 3D realistic mesh is conceived, with a point by point characterization of each single geometric element. The FE models are analyzed under seismic loads acting along geometric axes of the plan section, with non-linear dynamic excitation assumptions. A damage-plasticity material model exhibiting softening in both tension and compression, already available in the commercial code Abaqus, is used for masonry. Non-linear dynamic analyses are performed along both the X and Y directions with a real accelerogram scaled to different peak ground accelerations. Some results presented in this paper show the high vulnerability of ancient masonry towers under horizontal loads.

  11. Experimental research into dynamic properties of masonry barrel vaults non-reinforced and reinforced with carbon composite strips

    Czech Academy of Sciences Publication Activity Database

    Zigler, R.; Witzany, J.; Makovička, D.; Urushadze, Shota; Pospíšil, Stanislav; Kubát, J.; Kroftová, K.

    2016-01-01

    Roč. 2016, č. 3 (2016) ISSN 1805-2576 Institutional support: RVO:68378297 Keywords : rehabilitation * strengthening * masonry vaults * FRP fabrics * dynamic load * static load Subject RIV: JM - Building Engineering https://doaj.org/article/a4197d0d1b974dbeadf9188398d45fc8

  12. Effect of filler types on physical, mechanical and microstructure of self compacting concrete and Flow-able concrete

    Directory of Open Access Journals (Sweden)

    Hafez E. Elyamany

    2014-06-01

    Full Text Available The objective of this study is to evaluate the effect of various filler types on the fresh and hardened properties of self-compacting concrete (SCC and Flow-able concrete. For this purpose, two groups of fillers were selected. The first group was pozzolanic fillers (silica fume and metakaolin while the second group was non-pozzolanic fillers (limestone powder, granite dust and marble dust. Cement contents of 400 kg/m3 and 500 kg/m3 were considered while the used filler material was 7.5%, 10% and 15%. Slump and slump flow, T50, sieve stability and bleeding tests were performed on fresh concrete. The studied hardened properties included unit weight, voids ratio, porosity, and water absorption and cube compressive strength. In addition, thermo-gravimetric analysis, X-ray diffraction analysis and scanning electronic microscope were performed. The test results showed that filler type and content have significant effect on fresh concrete properties where non-pozzolanic fillers improve segregation and bleeding resistance. Generally, filler type and content have significant effect on unit weight, water absorption and voids ratio. In addition, non-pozzolanic fillers have insignificant negative effect on concrete compressive strength. Finally, there was a good correlation between fresh concrete properties and hardened concrete properties for SCC and Flow-able concrete.

  13. New generation concretes including reactive powder concretes

    Directory of Open Access Journals (Sweden)

    Stefania Grzeszczyk

    2015-09-01

    Full Text Available Based on a broad literature review, this paper presents characteristics of new generation composites on the basis of cements which are applied in engineering structures and in rehabilitation of structures. The role of cement, microfillers, superplasticizers and fibers in the above stated composites i.e. factors which allow for the maximum packing of particles in the cement matrix and a minimum pore volume, and the increase in composite bending strength, have been discussed. Special attention was paid to Reactive Powder Concrete in which coarse aggregate was replaced by ground quartz and sand. Such composites contain active microfillers and the applied new-generation superplasticizers allow us to decrease the water-cement ratio in the composite up to 0.2. Whereas, steel fibre additive allows us to significantly improve the bending strength.The paper presents the properties of the excellent Ductal — a composite from Reactive Powder Concrete, which at compressive strength from 180 to 230 MPa achieves the tensile strength of 30 to 50 MPa. Its application allows us to create slim profiles and tall light and slender, and simultaneously durable and corrosion-resistant structural elements of considerable span. This paper gives a few examples of Ductal application in practice.[b]Keywords[/b]: civil engineering, composite materials, reactive powder concrete

  14. Recycled Concrete as Aggregate for Structural Concrete Production

    Directory of Open Access Journals (Sweden)

    Mirjana Malešev

    2010-04-01

    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  15. Usage of Crushed Concrete Fines in Decorative Concrete

    Science.gov (United States)

    Pilipenko, Anton; Bazhenova, Sofia

    2017-10-01

    The article is devoted to the questions of usage of crushed concrete fines from concrete scrap for the production of high-quality decorative composite materials based on mixed binder. The main problem in the application of crushed concrete in the manufacture of decorative concrete products is extremely low decorative properties of crushed concrete fines itself, as well as concrete products based on them. However, crushed concrete fines could have a positive impact on the structure of the concrete matrix and could improve the environmental and economic characteristics of the concrete products. Dust fraction of crushed concrete fines contains non-hydrated cement grains, which can be opened in screening process due to the low strength of the contact zone between the hydrated and non-hydrated cement. In addition, the screening process could increase activity of the crushed concrete fines, so it can be used as a fine aggregate and filler for concrete mixes. Previous studies have shown that the effect of the usage of the crushed concrete fines is small and does not allow to obtain concrete products with high strength. However, it is possible to improve the efficiency of the crushed concrete fines as a filler due to the complex of measures prior to mixing. Such measures may include a preliminary mechanochemical activation of the binder (cement binder, iron oxide pigment, silica fume and crushed concrete fines), as well as the usage of polycarboxylate superplasticizers. The development of specific surface area of activated crushed concrete fines ensures strong adhesion between grains of binder and filler during the formation of cement stone matrix. The particle size distribution of the crushed concrete fines could achieve the densest structure of cement stone matrix and improve its resistance to environmental effects. The authors examined the mechanisms of structure of concrete products with crushed concrete fines as a filler. The results of studies of the properties of

  16. Building America Case Study: Retrofit Measure for Embedded Wood Members in Insulated Mass Masonry Walls, Lawrence, Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    2015-10-01

    ?There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw have known solutions. But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content and relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100 percent RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated vs. non-insulated joist pockets do not show large differences. South facing joists have safe (10-15 percent) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

  17. Studies of historic concrete

    International Nuclear Information System (INIS)

    Jull, S.P.; Lees, T.P.

    1990-01-01

    Underground concrete repositories for nuclear waste will have to maintain their integrity for hundreds of years. This study examines ancient concretes and assesses the suitability of equivalent modern materials for underground storage. Thirty four ancient samples have been obtained from Great Britain, Austria and Italy. One 19th century sample was also collected. The samples were examined using a variety of analytical techniques (including scanning electron microscopy, optical microscopy, chemical analysis and pH determination). The samples were also subjected to a range of physical tests. Most of the samples examined were very weak and porous although they had retained full structural integrity. With the exception of the 19th century sample, none of the concretes had maintained pH alkaline enough to immobilize radionuclides. Hydrated calcium silicates have been detected in some samples which are similar to those observed in modern Portland cement concretes. These stable cementitious species have endured for almost two thousand years. All the ancient concretes and mortars examined contained natural pozzolanic material or crushed burnt clay. This may have had some effect on the reduction in alkalinity although the main reason was full carbonation of calcium hydroxide

  18. Durability of lightweight concrete : Phase I : concrete temperature study.

    Science.gov (United States)

    1968-08-01

    This report describes a study conducted to determine the temperature gradient throughout the depth of a six inch concrete bridge deck. The bridge deck selected for study was constructed using lightweight concrete for the center spans and sand and gra...

  19. Vision 2030. A Vision for the U.S. Concrete Industry

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2001-01-01

    On September 27, 2000, the concrete industry's Strategic Development Council hosted a Concrete Vision Workshop in Chicago, Illinois. Meeting participants included over 50 concrete, cement, and other allied industry chief executive officers, presidents, vice-presidents, laboratory and industry research managers, and government representatives. Participants discussed the state of the concrete industry 30 years ago, the state of the current industry, and their vision for the United States concrete industry in 2030. Moreover, they identified specific goals to achieve the industry's Vision 2030. This document, Vision 2030, is the product of that workshop and the comments received after a broad industry review.

  20. Using of Stone Flour from Some Mineral Rocks in Modern Concrete

    Science.gov (United States)

    Roman, Moskvin; Elena, Belyakova; Marina, Moroz

    2018-03-01

    There is shown the possibility of using mill ground rocks in SCC without deterioration of rheological properties of concrete mixtures. Obtained high-strength concrete of the new generation with high technical and economic indices and low unit costs per unit of cement strength.

  1. Concrete Cover in Thin-Wall Reinforced Concrete Floating Piers

    Science.gov (United States)

    1976-07-01

    application of a waterproof material to the exterior surface of the concrete vessel, before immersion in seawater or brine solutions, will prevent...introduction to prestressed concrete: Volume 1. Concrete Publications Ltd., London. pp. 343-344. 17. Chapman, C. M. (1911). The effect of electrolysis on...of concrete in brine storage tanks. Proc. ACT, 44:141-147; discussion, 44:148-1 thru 148-3. 35. Kuenning, W. H. et al. (1966). Guide for the

  2. Characterisation of an unprocessed landfill ash for application in concrete.

    Science.gov (United States)

    Snelson, David G; Kinuthia, John M

    2010-11-01

    An investigation was carried out to establish the physical, mechanical and durability characteristics of an unprocessed pulverised fuel ash (PFA) from a former landfill site at the Power Station Hill near Church Village, South Wales, United Kingdom. This was aimed at establishing the suitability of the ash in the construction of the Church Village Bypass (embankment and pavement) and also in concrete to be used in the construction of the proposed highway. Concrete made using binder blends using various levels of PFA as replacement to Portland cement (PC) were subjected to compressive strength tests to establish performance. The concrete was also subjected to sodium sulphate attack by soaking concrete specimens in sulphate solution to establish performance in a sulphatic environment. Strength development up to 365 days for the concrete made with PC-PFA blends as binders (PC-PFA concrete), and 180 days for the PC-PFA paste, is reported. The binary PC-PFA concrete did not show good early strength development, but tended to improve at longer curing periods. The low early strength observed means that PC-PFA concrete can be used for low to medium strength applications for example blinding, low-strength foundations, crash barriers, noise reduction barriers, cycle paths, footpaths and material for pipe bedding. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Water Entrainment in Concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    This report gives a survey of different techniques for incorporation of designed, water-filled cavities in concrete: Water entrainment. Also an estimate of the optimum size of the water inclusions is given. Water entrainment can be used to avoid self-desiccation and self-desiccation shrinkage...... during hydration [1,26]. What is needed is some sort of container which retains the shape of the water when mixed into the concrete. The container may function based on several different physical or chemical principles. Cells and gels are examples of containers found in nature. A cell membrane provides...... a boundary to water, whereas a polymer network incorporates water in its intersticious space with its affinity due to interaction energy and polymer entropy. Such containers allow water to be stored as an entity. In relation to concrete the water encapsulation may be accomplished either before or after start...

  4. Drying of Concrete

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Geiker, Mette Rica; Nygaard, Peter Vagn

    2002-01-01

    Estimated and measured relative humidity (RH) change during drying are compared for two concretes, 1: w/c=0.46 and 2: w/(c+0.5fa+2sf)=0.50. The estimations were undertaken by means of the Swedish program TorkaS 1.0. Measurements were performed by RH-sensors type Humi-Guard. Drying of 150 mm thick...... samples from sides at 60% RH and 22 °C took place from 4 to 56 days after casting. At the end of the drying period the measured RH was about 4% lower than the estimated RH at 1/5th depth from the exposed surface for both concretes. In the middle of the samples, the measured RH of concretes 1 and 2 were 2...

  5. Mechanical behavior analysis of small-scale modeling of ceramic block masonry structures: geometries effect

    Directory of Open Access Journals (Sweden)

    E. Rizzatti

    Full Text Available This paper presents the experimental results of a research program with ceramic block masonry under compression. Four different block geometries were investigated. Two of them had circular hollows with different net area. The third one had two rectangular hollow and the last block was with rectangular hollows and a double central webs. The prisms and walls were built with two mortar type 1:1:6 (I and 1:0,5:4 (II (proportions by volume of cement: lime: sand. One:three small scale blocks were used to test block, prisms and walls on compression. It was possible to conclude that the block with double central webs gave better results of compressive strength showing to be more efficient. The mortar didn't influenced the compressive strength of prisms and walls.

  6. Non-linear characterisation of the physical model of an ancient masonry bridge

    International Nuclear Information System (INIS)

    Fragonara, L Zanotti; Ceravolo, R; Matta, E; Quattrone, A; De Stefano, A; Pecorelli, M

    2012-01-01

    This paper presents the non-linear investigations carried out on a scaled model of a two-span masonry arch bridge. The model has been built in order to study the effect of the central pile settlement due to riverbank erosion. Progressive damage was induced in several steps by applying increasing settlements at the central pier. For each settlement step, harmonic shaker tests were conducted under different excitation levels, this allowing for the non-linear identification of the progressively damaged system. The shaker tests have been performed at resonance with the modal frequency of the structure, which were determined from a previous linear identification. Estimated non-linearity parameters, which result from the systematic application of restoring force based identification algorithms, can corroborate models to be used in the reassessment of existing structures. The method used for non-linear identification allows monitoring the evolution of non-linear parameters or indicators which can be used in damage and safety assessment.

  7. A vibration-based health monitoring program for a large and seismically vulnerable masonry dome

    Science.gov (United States)

    Pecorelli, M. L.; Ceravolo, R.; De Lucia, G.; Epicoco, R.

    2017-05-01

    Vibration-based health monitoring of monumental structures must rely on efficient and, as far as possible, automatic modal analysis procedures. Relatively low excitation energy provided by traffic, wind and other sources is usually sufficient to detect structural changes, as those produced by earthquakes and extreme events. Above all, in-operation modal analysis is a non-invasive diagnostic technique that can support optimal strategies for the preservation of architectural heritage, especially if complemented by model-driven procedures. In this paper, the preliminary steps towards a fully automated vibration-based monitoring of the world’s largest masonry oval dome (internal axes of 37.23 by 24.89 m) are presented. More specifically, the paper reports on signal treatment operations conducted to set up the permanent dynamic monitoring system of the dome and to realise a robust automatic identification procedure. Preliminary considerations on the effects of temperature on dynamic parameters are finally reported.

  8. Elastic, plastic, fracture analysis of masonry arches: A multi-span bridge case study

    Science.gov (United States)

    Lacidogna, Giuseppe; Accornero, Federico

    2018-01-01

    In this work a comparison is presented between elastic, plastic, and fracture analysis of the monumental arch bridge of Porta Napoli, Taranto (Italy). By means of a FEM model and applying the Mery's Method, the behavior of the curved structure under service loads is verified, while considering the Safe Theorem approach byHeyman, the ultimate carrying capacity of the structure is investigated. Moreover, by using Fracture Mechanics concepts, the damage process which takes place when the conditions assessed through linear elastic analysis are no longer valid, and before the set-in of the conditions established by means of the plastic limit analysis, is numerically analyzed. The study of these transitions returns an accurate and effective whole service life assessment of the Porta Napoli masonry arch bridge.

  9. Force-displacement response of unreinforced masonry walls for seismic design

    International Nuclear Information System (INIS)

    Petry, S.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology EPFL contributes to the improvement of the design and assessment methods for unreinforced masonry (URM) wall structures built with modern hollow core clay bricks. First, an experimental campaign on the lateral nonlinear in-plane response of URM walls is presented; secondly, an existing dataset on URM walls is extended and reanalysed. A newly developed mechanical model which describes the full force-displacement response of URM walls is described. Two series of URM walls tested under lateral in-plane loading are presented. Throughout the quasi-cyclic tests of all URM walls, the deformations were recorded using a digital photogrammetric measurement system which tracked the displacement field of the walls. Based on these findings, a new mechanical model is proposed which describes the nonlinear force-displacement response of flexural dominated URM walls up to near collapse

  10. Use of fiber reinforced concrete for concrete pavement slab replacement.

    Science.gov (United States)

    2014-03-01

    Unlike ordinary concrete pavement, replacement concrete slabs need to be open to traffic within 24 hours (sooner in : some cases). Thus, high early-strength concrete is used; however, it frequently cracks prematurely as a result of high : heat of hyd...

  11. Simplified Assessment of R3 Nominal Assurance Degree to Seismic Action of the Existing Masonry Dwellings

    Directory of Open Access Journals (Sweden)

    Teodor Broşteanu

    2008-01-01

    Full Text Available This paper refers to the assessment of the performance level of a building for a given seismic hazard level. Building performance level describes the expected seismic performance given by the computation of R3 Nominal Assurance Degree to Seismic Action of the Existing Masonry Dwellings and Monumental Buildings according to the Romanian Norm P100:1992 [1], modified on 1996 with the chapters 11 and 12, until the Part 3 of P100-1:2006 [2], will be performed for the Assessment and Strengthening Structural Design of the Seismic Vulnerable, Existing Buildings, in the frame of SR EN 1998-1:2004 EC8 [3]. The framing of damages into the potential risk degrees has a social and economic impact. Assessment and retrofitting of the existing buildings have represented a huge engineering challenge as a distinct problem versus a new building design. The performance level of a vulnerable existing building shows us the expected seismic performance level due to the classified damages, the pattern of cracks, the interruption of function, the economic losses and the needed interventions, all in function of the importance class of building on next life span of use. On recommends the computation of R (R3 Nominal Assurance Degree to Seismic Action of the Vulnerable Dwellings for the assessing and strengthening design, in comparison to both norms because of the bearing conventional seismic load computed by [1], will result less than the value which will be computed by the Part 3 of P100-1:2006, i.e. the norm P100:1992 is more severe. In the case of the breakable fracture probability of the existing structural masonry members, one recommends a bigger value of ? – reduction factor unless the given values by [1] for a new structure with a high ductility, especially for the deflections calibration on the same limit state.

  12. Technical Note: Alterations in the stone masonry of the Capitol Room of Sevilla City Hall

    Directory of Open Access Journals (Sweden)

    García Navarro, J.

    2006-12-01

    Full Text Available The main aim of this work has been to determine the causes of stone loss (small particles and one larger piece and mortar loss in the coffered vault of the Capitol Room in the City Hall of Seville. The analyses and assays carried out during the course of this research have revealed that this masonry comprises a covering of oil paints over mortar-stucco of calcite, quartz, gypsum,and lead white with linseed oil when the walls were not covered. In addition, it was confirmed that the installation of air-conditioning caused a change in the humidity and temperature in the vault, aggravated by the elimination of the cross-ventilation that the structure had since it was built. The combination of these two circumstances likely triggered the pathology in the masonry.Este trabajo ha tenido como objetivo principal determinarlas causas que han originado desprendimientos de partículas y un fragmento importante de las piedras y del mortero que conforman la bóveda-artesonado de la Sala Capitular del Ayuntamiento de Sevilla. Los diferentes análisis y ensayos realizados evidencian que estas fábricas tienen un revestimiento realizado a base de pinturas al óleo sobre estuco-mortero de calcita, cuarzo, yeso y presencia de blanco de plomo con impregnación de aceite de linaza, en tanto que las fábricas de los muros no tienen revestimiento alguno. Igualmente se ha constatado el cambio de la humedad-temperatura ambiental en la bóveda, generado por la implantación de aire acondicionado y la eliminación de la ventilación cruzada natural que tenía desde su construcción. La conjunción de ambas acciones parece ser el desencadenante de las anomalías reseñadas.

  13. Properties of normal- and high-strength concrete containing metakaolin

    Energy Technology Data Exchange (ETDEWEB)

    Balaguru, P. [Rutgers State Univ. of New Jersey, NJ (United States)

    2001-07-01

    A study was conducted which confirmed the findings of an earlier study that showed that the addition of metakaolin in concrete can improve the compressive strength of concrete and reduce its permeability. Metakaolin is made by calcining purified kaolinite at a specific temperature range. It combines with calcium hydroxide to form calcium silicate and calcium aluminate hydrates. The main objective of this study was to examine the influence of 5 and 9 per cent of metakaolin on plastic and hardened concrete properties. The independent variables were the size of the compressive strength, the type of cement, type of curing and the age at the time of testing. The specimens were cured at 100 per cent relative humidity at 22 degrees C or in warm water maintained at 50 degrees C. The response variables were slump, unit weight, air content, and concrete temperature for fresh concrete. Other variables were compressive strength, modulus of elasticity, modulus of rupture and rapid chloride permeability for hardened concrete. It was shown that air content and curing temperature was not affected by metakaolin, and the effect on unit weight was negligible. Metakaolin was found to improve early compressive strength and also improved the strength at later ages. It also enhances the modulus of elasticity and has little effect on modulus rupture. Control concretes had a low chloride ion permeability. Metakaolin reduced the permeability even further. 8 refs., 11 tabs., 7 figs.

  14. Sprayed concrete linings

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, D.

    1999-12-01

    Sprayed concrete, or shotcrete, was invented in the 1920s for preserving dinosaur skeletons and was used underground initially in coalmines for the preservation and fine proofing of timber supports. Its use as a support lining in rock tunnelling was developed in the 1950s and 60s. The article surveys equipment available from major manufacturers and suppliers of concrete spraying equipment (Aliva, Cifa, GIA, Industri, Ingersoll Rand, etc.), specialist cement and additive manufacturers (Castle, Cement, Moria Carbotech). manufacturers of lattice girders and fibre reinforcement, and manufacturers of instrumentation for tunnel linings. 5 tabs., 9 photos.

  15. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  16. Structural Materials: 95. Concrete

    International Nuclear Information System (INIS)

    Naus, Dan J.

    2012-01-01

    Nuclear power plant concrete structures and their materials of construction are described, and their operating experience noted. Aging and environmental factors that can affect the durability of the concrete structures are identified. Basic components of a program to manage aging of these structures are identified and described. Application of structural reliability theory to devise uniform risk-based criteria by which existing facilities can be evaluated to achieve a desired performance level when subjected to uncertain demands and to quantify the effects of degradation is outlined. Finally, several areas are identified where additional research is desired.

  17. Improved concretes for corrosion resistance

    Science.gov (United States)

    1997-07-01

    The deterioration of various reinforced concrete bridge components containing conventional black steel reinforcement is the most important problem facing U.S. highway agencies. A major cause of this concrete deterioration (cracking, delamination, and...

  18. 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...

  19. Cylindrical prestressed concrete pressure vessel for a nuclear power plant

    International Nuclear Information System (INIS)

    Horner, M.; Hodzic, A.; Haferkamp, D.

    1976-01-01

    A prestressed concrete pressure vessel for a HTGR is proposed which encloses, in addition to the reactor core, not only the heat-exchanging facilities but also the turbine unit. The reinforcement of the cylindrical concrete body is to be carried out with special care, it is provided for horizontal tendons, the prestressed concrete pressure vessel has a wire-winding device, while the longitudinal reinforcement is achieved by tendous guided in parallel to the vesses axes through the interspaces between the pods. (UWI) [de

  20. APPLICATION OF COMPUTER SIMULATION IN THE EVALUATION OF THE STRESS-STRAIN STATE OF LOAD-BEARING STRUCTURES OF BUILDINGS MASONRY

    Directory of Open Access Journals (Sweden)

    Anatoliy I. Bedov

    2017-03-01

    Full Text Available The results of studies on the analysis of the stress-strain state of the structures of bearing walls of high-hollow pottery. The way of modeling masonry finite element method. The experimental study of masonry structures produced in the Republic of Bashkortostan high-hollow pottery, set the nature of their work load, the mechanism of destruction. The results of the comparative evaluation of the calculations in the software package and the traditional “manual” calculation.