Effects of Adhesive Connection on Composite Action between FRP Bridge Deck and Steel Girder

NARCIS (Netherlands)

Jiang, X.; Luo, Chengwei; Qiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2017-01-01

The FRP-steel girder composite bridge system is increasingly used in new constructions of bridges as well as rehabilitation of old bridges. However, the understanding of composite action between FRP decks and steel girders is limited and needs to be systematically investigated. In this paper,

A calculation model for the noise from steel railway bridges

NARCIS (Netherlands)

Janssens, M.H.A.; Thompson, D.J.

1996-01-01

The sound level of a train crossing a steel railway bridge is usually about 10 dB higher than on plain track. In the Netherlands there are many such bridges which, for practical reasons, cannot be replaced by more intrinsically quiet concrete bridges. A computational model is described for the

Dragon bridge - the world largest dragon-shaped (ARCH steel bridge as element of smart city

Directory of Open Access Journals (Sweden)

Chinh Luong Minh

2016-01-01

Full Text Available Dragon Bridge - The world’s largest dragon-shaped steel bridge, with an installation cost of $85 million USD, features 6 lanes for two separate directions, 666 meters of undulating steel in the shape of a dragon in the Ly Dynasty, the symbol of prosperity in Vietnamese culture. This unique and beautifully lit bridge, which also breathes fire and sprays water. It’s the purposeful integration of the lighting hardware articulates the dragon’s form, and the fire-breathing dragon head. This project transcends the notion of monumental bridge with dynamic colour-changing lighting, creating an iconic sculpture in the skyline that is both reverent and whimsical. The signature feature of the bridge was the massive undulating support structure resembling a dragon flying over the river. The dragon is prominent in Vietnamese culture as a symbol of power and nobility. Dragon Bridge stands out as a model of innovation. It has received worldwide attention in the design community and from the global media for its unique arch support system. Dragon Bridge serves as an example of how aesthetic quality of a design can serve cultural, economic and functional purposes. The article presents design solutions of the object and the evaluation of the technical condition before putting the facility into service.

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

OpenAIRE

Kang, Donghoon; Chung, Wonseok

2013-01-01

This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sen...

Water flow patterns induced by bridge oscillation of magnetic fluid between two permanent magnets subjected to alternating magnetic field

International Nuclear Information System (INIS)

Sudo, Seiichi; Yamamoto, Kazuki; Ishimoto, Yukitaka; Nix, Stephanie

2017-01-01

This paper describes the characteristics of water flow induced by the bridge oscillation of magnetic fluid between two permanent magnets subject to an external alternating magnetic field. The magnetic fluid bridge is formed in the space between a pair of identical coaxial cylindrical permanent magnets submerged in water. The direction of alternating magnetic field is parallel /antiparallel to the magnetic field produced by two permanent magnets. The magnetic fluid bridge responds to the external alternating magnetic field with harmonic oscillation. The oscillation of magnetic fluid bridge generates water flow around the bridge. Water flow is visualized using a thin milk film at the container bottom. Water flows are observed with a high-speed video camera analysis system. The experimental results show that the flow pattern induced by the bridge oscillation depends on the Keulegan–Carpenter number.

Water flow patterns induced by bridge oscillation of magnetic fluid between two permanent magnets subjected to alternating magnetic field

Energy Technology Data Exchange (ETDEWEB)

Sudo, Seiichi, E-mail: sudo@akita-pu.ac.jp [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan); Yamamoto, Kazuki [Graduate School of Engineering, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Ishimoto, Yukitaka; Nix, Stephanie [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan)

2017-06-01

This paper describes the characteristics of water flow induced by the bridge oscillation of magnetic fluid between two permanent magnets subject to an external alternating magnetic field. The magnetic fluid bridge is formed in the space between a pair of identical coaxial cylindrical permanent magnets submerged in water. The direction of alternating magnetic field is parallel /antiparallel to the magnetic field produced by two permanent magnets. The magnetic fluid bridge responds to the external alternating magnetic field with harmonic oscillation. The oscillation of magnetic fluid bridge generates water flow around the bridge. Water flow is visualized using a thin milk film at the container bottom. Water flows are observed with a high-speed video camera analysis system. The experimental results show that the flow pattern induced by the bridge oscillation depends on the Keulegan–Carpenter number.

Fatigue-Prone Details in Steel Bridges

Directory of Open Access Journals (Sweden)

Mohsen Heshmati

2012-11-01

Full Text Available This paper reviews the results of a comprehensive investigation including more than 100 fatigue damage cases, reported for steel and composite bridges. The damage cases are categorized according to types of detail. The mechanisms behind fatigue damage in each category are identified and studied. It was found that more than 90% of all reported damage cases are of deformation-induced type and generated by some kind of unintentional or otherwise overlooked interaction between different load-carrying members or systems in the bridge. Poor detailing, with unstiffened gaps and abrupt changes in stiffness at the connections between different members were also found to contribute to fatigue cracking in many details.

Influence of microclimate on the sustainability and reliability of weathering steel bridge

Science.gov (United States)

Kubzova, M.; Krivy, V.; Kreislova, K.

2018-04-01

Reliability and sustainability of bridge structures designed from weathering steel are influenced by the development of a sufficiently protective layer of corrosion products on its surface. The development of this protective layer is affected by several parameters such as air pollution around the bridge structure, the microclimate under the bridge, the location of surface within the bridge structure and the time of wetness. Design of structural details also significantly influences the development of the protective corrosion layer. The article deals with the results of the experimental tests carried out on the road bridge located in the city of Ostrava in the Czech Republic. The development of the protective corrosion layer on the surface of the bridge is significantly influenced by the intensive traffic under the bridge construction and the design solution of the bridge itself. Attention is focused mainly on the influence of chloride deposition on the protective function of the corrosion layer. Corrosion samples were placed on the bridge to evaluate the influence of the above-mentioned parameters. The deposition rate of chlorides spreading from the road to surfaces of the steel structure is also measured.

Static and fatigue investigation of second generation steel free bridge decks

International Nuclear Information System (INIS)

Klowak, C.; Memon, Amjad H.; Mufti, Aftab A.

2006-01-01

This paper outlines the static and fatigue behavior of two different cast-in-place second generation steel-free bridge decks, which are: hybrid carbon fiber reinforced polymer (CFRP); and glass fiber reinforced polymer (GFRP) and steel strap design. Although cast monolithically, the first deck slab was divided into three segments with different reinforcement configurations. All three segments were tested under a 222kN cyclic loading to investigate fatigue behavior. The second bridge deck comprised an internal panel and two cantilevers and was equipped with a civionics system. The internal panel static test that this paper deals with is useful in the development of fatigue theory derived from fatigue testing of the first bridge deck. Test results form the cyclic loading of the first bridge deck indicated that the cross-sectional area of the reinforcement used in the test bridge deck can be reduced by 40% based on the reinforcement provided in the deck under service loads. The hybrid system also reduced the development of longitudinal crack widths to approximately 0.4 mm under service conditions, compared to the cracks that occurred approximately halfway between adjacent bridge girders that were determined to be roughly 1 mm in several first generation steel-free bridge decks constructed in Canada. Civionics, also discussed in the paper, is a new term coined from Civil-Electronics, which is the application of electronics to civil structures. The Civionics Specifications (2004) developed by ISIS Canada researchers are a helpful design tool for engineers and contractors to develop civionics and structural health monitoring systems for civil infrastructure that will last the lifetime of a structure. The use of civionics for the second test bridge deck ensured the survival of 100% of the 63 internal sensors throughout the rigors of the construction and casting of the deck. (author)

Estimation of Structure-Borne Noise Reduction Effect of Steel Railway Bridge Equipped with Floating Ladder Track and Floating Reinforced-Concrete Deck

Science.gov (United States)

Watanabe, Tsutomu; Sogabe, Masamichi; Asanuma, Kiyoshi; Wakui, Hajime

A number of steel railway bridges have been constructed in Japan. Thin steel members used for the bridges easily tend to vibrate and generate structure-borne noise. Accordingly, the number of constructions of steel railway bridges tends to decrease in the urban areas from a viewpoint of environmental preservation. Then, as a countermeasure against structure-borne noise generated from steel railway bridges, we have developed a new type of the steel railway bridge equipped with a floating-ladder track and a floating reinforced-concrete (RC) deck. As a result of train-running experiment, it became apparent that the new steel railway bridge installed by double floating system has reduced a vibration velocity level by 10.5 dB(A) at main girder web as compared with a steel railway bridge installed by directly fastened track. This reduction effect was achieved by the ladder track and RC deck supported by resilient materials.

Structural health monitoring in end-of-life prediction for steel bridges subjected to fatigue cracking

NARCIS (Netherlands)

Attema, T.; Courage, W.M.G.; Maljaars, J.; Meerveld, H. van; Paulissen, J.H.; Pijpers, R.J.M.; Slobbe, A.T.

2015-01-01

This paper presents a monitoring and modelling methodology to assess the current and future conditions of steel bridges subjected to fatigue cracking. Steel bridges are subjected to fatigue cracking as a result of fluctuating stresses caused by the crossing of heavy vehicles. Specifically for

Research on construction technology for orthotropic steel deck pavement of Haihe River Chunyi Bridge

Science.gov (United States)

Xue, Y. C.; Qian, Z. D.; Zhang, M.

2017-01-01

In order to ensure the good service quality of orthotropic steel deck pavement of Haihe River Chunyi Bridge in Tianjin, and to reduce the occurrence of pavement diseases like lateral and longitudinal cracks, the key working procedures such as steel deck cleaning, anticorrosive coating, bonding layer spraying, seam cutting, epoxy asphalt concrete’s mixing, transportation, paving and compaction were studied. The study was based on the main features of epoxy asphalt concrete which is the pavement materials of Haihe River Chunyi Bridge, and combined with the basic characteristics and construction conditions of Haihe River Chunyi Bridge. Furthermore, some processing measures like controlling time and temperature, continuous paving with two pavers, lateral feeding, and improving the compaction method were proposed. The project example shows that the processing measures can effectively solve the technical difficulties in the construction of orthotropic steel deck pavement of Haihe River Chunyi Bridge, can greatly improve the construction speed and quality, and can provide reference for the same kinds of orthotropic steel deck pavement construction.

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

Directory of Open Access Journals (Sweden)

Donghoon Kang

2013-01-01

Full Text Available This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sensor arrays is proposed in order to measure curvature changes in this study. They are embedded in a full-scale test bridge and measured local strains, which are finally converted to curvatures. From the result of curvature changes, it is successfully ensured that the key idea of the proposed bridge, expected theoretically, is viable.

Effects of Adhesive Connection on Composite Action between FRP Bridge Deck and Steel Girder

Directory of Open Access Journals (Sweden)

Xu Jiang

2017-01-01

Full Text Available The FRP-steel girder composite bridge system is increasingly used in new constructions of bridges as well as rehabilitation of old bridges. However, the understanding of composite action between FRP decks and steel girders is limited and needs to be systematically investigated. In this paper, depending on the experimental investigations of FRP to steel girder system, the Finite Element (FE models on experiments were developed and analyzed. Comparison between experiments and FE results indicated that the FE models were much stiffer for in-plane shear stiffness of the FRP deck panel. To modify the FE models, rotational spring elements were added between webs and flanges of FRP decks, to simulate the semirigid connections. Numerical analyses were also conducted on four-point bending experiments of FRP-steel composite girders. Good agreement between experimental results and FE analysis was achieved by comparing the load-deflection curves at midspan and contribution of composite action from FRP decks. With the validated FE models, the parametric studies were conducted on adhesively bonded connection between FRP decks and steel girders, which indicated that the loading transfer capacity of adhesive connection was not simply dependent on the shear modulus or thickness of adhesive layer but dominated by the in-plane shear stiffness K.

Optimal, Generic Planning of Maintenance and Inspection of Steel Bridges

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Faber, Michael Havbro

2002-01-01

Fatigue damage is an important deterioration mechanism for steel bridges. This paper describes a simplified and generic approach for reliability and risk based inspection planning of fatigue sensitive structural details. Fatigue sensitive details are categorized according to their loading charact...

Conversion of a Temporary Tent with Steel Frame into a Permanent Warehouse

Science.gov (United States)

Georgescu, Mircea; Ungureanu, Viorel; Grecea, Daniel; Petran, Ioan

2017-10-01

The paper is dealing with the problem of a functional conversion (involving both architectural and structural issues) applied to the case of an industrial building. As well known, temporary tents, designed according to the European Code EN13782, represent a remarkable stake on the building market and a fast and practical solution for some situations. It is exactly the case approached by the paper, where the investor has initially decided to erect on his platform a provisional shelter for agricultural machines and subsequent staff, built of a light steel structure covered by PVC roofing and cladding. This temporary tent has been acquired from a specialized supplier in form of a series product. After using the tent for a number of years, the investor has decided to convert the existing structure from architectural and structural point of view by switching to a permanent structure designed accordingly. Important changes were thus imposed both to the architectural part (technological flows, openings, facades) and especially to the structural part where this switch imposed a re-design to the codes of permanent structures (especially as far as climatic loadings are concerned). The required architectural change implied the building of a 70 cm high concrete plinth and replacing the PVC membrane temporary roofing and cladding by permanent 60 mm thick PUR sandwich panels. Together with a new system of openings this has led to renewed facades of the buildings. As for the structural change, the required conversion has imposed a thorough checking of the existing steel structure (very slender and typical to a tent) in view of transforming it into a permanent structure. The consolidation measures of the existing galvanized steel structure are described, together with the measures applied at infrastructure level in order to implement the required conversion.

Design and evaluation of steel bridges with double composite action

Science.gov (United States)

2010-02-01

This report presents findings from a cooperative USF/URS/FDOT research study undertaken to develop design rules for : double composite steel bridges. In the study, a 48 ft long, 16 ft wide, 4 ft. 10 in. deep trapezoidal HPS 70W box section : desig...

Seismic damage sensing of bridge structures with TRIP reinforcement steel bars

Science.gov (United States)

Adachi, Yukio; Unjoh, Shigeki

2001-07-01

Intelligent reinforced concrete structures with transformation-induced-plasticity (TRIP) steel rebars that have self-diagnosis function are proposed. TRIP steel is special steel with Fe-Cr based formulation. It undergoes a permanent change in crystal structure in proportion to peak strain. This changes from non-magnetic to magnetic steel. By using the TRIP steel rebars, the seismic damage level of reinforced concrete structures can be easily recognized by measuring the residual magnetic level of the TRIP rebars, that is directly related to the peak strain during a seismic event. This information will be most helpful for repairing the damaged structures. In this paper, the feasibility of the proposed intelligent reinforced concrete structure for seismic damage sensing is experimentally studied. The relation among the damage level, peak strain of rebars, and residual magnetic level of rebars of reinforced concrete beams implemented with TRIP steel bars was experimentally studied. As the result of this study, this intelligent structure can diagnose accumulated strain/damage anticipated during seismic event.

Mechanism of Fatigue Crack Growth of Bridge Steel Structures

Directory of Open Access Journals (Sweden)

Zhu H.

2016-12-01

Full Text Available This study was carried out on the background of Sutong Bridge project based on fracture mechanics, aiming at analyzing the growth mechanism of fatigue cracks of a bridge under the load of vehicles. Stress intensity factor (SIF can be calculated by various methods. Three steel plates with different kinds of cracks were taken as the samples in this study. With the combination of finite element analysis software ABAQUS and the J integral method, SIF values of the samples were calculated. After that, the extended finite element method in the simulation of fatigue crack growth was introduced, and the simulation of crack growth paths under different external loads was analyzed. At last, we took a partial model from the Sutong Bridge and supposed its two dangerous parts already had fine cracks; then simulative vehicle load was added onto the U-rib to predict crack growth paths using the extended finite element method.

Study of displacements of a bridge abutment using FEM

Science.gov (United States)

Wymysłowski, Michał; Kurałowicz, Zygmunt

2016-06-01

Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Construction Simulation Analysis of 60m-span Concrete Filled Steel Tube arch bridge

Science.gov (United States)

Shi, Jing Xian; Ding, Qing Hua

2018-06-01

The construction process of the CFST arch bridge is complicated. The construction process not only affects the structural stress in the installation, but also determines the form a bridge and internal force of the bridge. In this paper, a 60m span concrete filled steel tube tied arch bridge is taken as the background, and a three-dimensional finite element simulation model is established by using the MIDAS/Civil bridge structure analysis software. The elevation of the main arch ring, the beam stress, the forces in hanger rods and the modal frequency of the main arch during the construction stage are calculated, and the construction process is simulated and analyzed. Effectively and reasonably guide the construction and ensure that the line and force conditions of the completed bridge meet the design requirements and provides a reliable technical guarantee for the safe construction of the bridge.

Numerical investigation into thermal load responses of steel railway bridge

Science.gov (United States)

Saravana Raja Mohan, K.; Sreemathy, J. R.; Saravanan, U.

2017-07-01

Bridge design requires consideration of the effects produced by temperature variations and the resultant thermal gradients in the structure. Temperature fluctuation leads to expansion and contraction of bridges and these movements are taken care by providing expansion joints and bearings. Free movements of a member can be restrained by imposing certain boundary condition but at the same time considerable allowances should be made for the stresses resulting from this restrained condition since the additional deformations and stresses produced may affect the ultimate and serviceability limit states of the structure. If the reaction force generated by the restraints is very large, then its omission can lead to unsafe design. The principal objective of this research is to study the effects of temperature variation on stresses and deflection in a steel railway bridge. A numerical model, based on finite element analysis is presented for evaluating the thermal performance of the bridge. The selected bridge is analyzed and the temperature field distribution and the corresponding thermal stresses and strains are calculated using the finite element software ABAQUS. A thorough understanding of the thermal load responses of a structure will result in safer and dependable design practices.

Laser welded steel sandwich panel bridge deck development : finite element analysis and stake weld strength tests.

Science.gov (United States)

2009-09-01

This report summarizes the analysis of laser welded steel sandwich panels for use in bridge structures and : static testing of laser stake welded lap shear coupons. Steel sandwich panels consist of two face sheets : connected by a relatively low-dens...

Vertical impedance measurements on concrete bridge decks for assessing susceptibility of reinforcing steel to corrosion

Science.gov (United States)

Bartholomew, Paul D.; Guthrie, W. Spencer; Mazzeo, Brian A.

2012-08-01

Corrosion is a pressing problem for aging concrete infrastructure, especially bridge decks. Because of its sensitivity to factors that affect corrosion of reinforcing steel in concrete, resistivity is an important structural health indicator for reinforced concrete structures. In this research, an instrument was developed to measure vertical impedance on concrete bridge decks. Measurements of vertical impedance on slabs prepared in the laboratory, on slabs removed from decommissioned bridge decks, and on an in-service bridge deck in the field demonstrate the utility of the new apparatus.

Research on structural dynamic characteristics of continuous steel box girder-bridge with lager ratio of wide-span

Directory of Open Access Journals (Sweden)

Yin Haijun

2018-01-01

Full Text Available Structure natural frequency and mode of vibration can not only reflect the structure modal parameters of dynamic properties, but also incarnate the dynamic evaluation characteristics of bridge structure. This paper applies ANSYS to establish the finite element model based on a continuous steel box girder bridge in order to obtain the corresponding modal analysis parameters. Through the environmental stimulation test, The results show that height of the steel box girder and the setting of diaphragm plate is reasonable, transverse space of piers not merely provide enough support but also ensure lateral stability of the bridge, as well as offering aside the maximum lateral clearance of the existing road. Meanwhile, the calculation results have important engineering practical values. which can provide basic data for the design, construction and maintenance of similar Bridges.

Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

Directory of Open Access Journals (Sweden)

Hao Wang

2014-01-01

Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

Microstructural characterisation and corrosion performance of old railway girder bridge steel and modern weathering structural steel

International Nuclear Information System (INIS)

Tewary, N.K.; Kundu, A.; Nandi, R.; Saha, J.K.; Ghosh, S.K.

2016-01-01

Highlights: • Microstructure and corrosion performance are compared for two structural steels. • Microstructure evolution shows primarily ferrite-pearlite in both the steels. • Steels show higher corrosion rate in 1% HCl solution than in 3.5% NaCl solution. • The corrosion products show the presence of oxide, hydroxide and oxy-hydroxides. • The corroded surface reveals morphologies like flowery, cotton balls and rosette. - Abstract: A comparison on microstructure and corrosion performance has been made between the two structural steels used in old railway girder bridge (Sample A) and modern grades of weathering structural steel (Sample B). The microstructures, viewed under optical microscope and scanning electron microscope (SEM), show mainly ferrite-pearlite phase constituents in both the steels, A and B. The phase fraction analysis shows higher amount of pearlite in steel A compared to that of steel B. The grain size of steel A is larger than that of steel B under identical processing condition. The immersion corrosion test in 3.5% NaCl shows that the corrosion rate of steel A increases with time, while the same for steel B decreases with time. On the other hand, corrosion test in 1% HCl shows that the corrosion rate of both steel A and B is higher as compared to that of NaCl which always decreases with time. The XRD analysis of corrosion products show the presence of many oxides, hydroxide and oxy-hydroxide like Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Akaganeite (β-FeOOH), Magnetite (Fe_3O_4) and Maghemite (γ-Fe_2O_3) in both the steels. The SEM images of corroded surfaces reveal different morphologies like flowery, cotton balls and rosette etc. which indicate that the corrosion products primarily contain Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH) and Akaganeite (β-FeOOH).

Dynamic and Fatigue Analysis of an 18th Century Steel Arch Bridge

International Nuclear Information System (INIS)

Boumechra, Nadir; Hamdaoui, Karim

2008-01-01

Within the 'Oran-Tlemcen' railway line realization project (159 km), several bridges were built by the Railroads Algerian West Company. 7 km from the east of Tlemcen city, this railway line must cross a very broken mountainous collar, that's why the French engineer 'Gustave Eiffel' was solicited to construct a 68 m length bridge. In 1890, an arch steel truss bridge was realized. The bridge presents 300 m of apron curvature radius and, currently, is considered as one of the most important monuments of the Algerian historical heritage. Considering the age of the bridge and the evolution of the railway loads in time, it was essential to check the good behavior of the studied structure. For that, analyses to verify the physical and mechanical properties of the growth iron members are made. A finite element model of the bridge was built and numerical simulations were drawn. The structural vibration conducted analysis permit to understand the behavior of this particular structure, then to evaluate (in detail) the rate of the structure fatigue

Self-supporting method; an alternative method for steel truss bridge element replacement

Science.gov (United States)

Arsyad, Muhammad; Sangadji, Senot; As'ad, Sholihin

2017-11-01

Steel truss bridge often requires replacement of its element due to serious damage caused by traffic accidents. This replacement is carried out using temporary supporting structure. It would be difficult when the available space for the temporary structure is quite limited and or the position of work is at a high elevation. The self-supporting method is proposed instead of temporary supporting structure. This paper will discuss an innovative method of bridge rehabilitation by utilizing the existing bridge structure. It requires such temporary connecting structure that installed on the existing bridge element, therefore, the forces during replacement process could be transferred to the bridge foundation directly. By taking the case on a steel truss bridge Jetis Salatiga which requires element replacement due to its damages on two main diagonals, a modeling is carried out to get a proper repair method. Structural analysis is conducted for three temporary connecting structure models: “I,” “V,” and triangular model. Stresses and translations that occur in the structure are used as constraints. Bridge bearings are modeled in two different modes: fixed-fixed system and fixed-free one. Temperature load is given in each condition to obtain the appropriate time for execution. The triangular model is chosen as the best one. In the fixed-fixed mode, this method can be carried out in a temperature range 27-28.8° C, while in fixed-free one, the temperature it is allowed between 27-43.4 °C. The D4 is dismantled first by cutting the D4 leaving an area of 1140.2 mm2 or 127 mm web length to enable plastic condition until the D4 collapses. At the beginning of elongation occurs, immediately performed a slowly jacking on a temporary connecting structure so that the force on D4 is gradually transferred to the temporary connecting structure then the D4 and D5 are set in their place.

Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members’ Joints

Directory of Open Access Journals (Sweden)

Gocál Jozef

2014-12-01

Full Text Available The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

Study of displacements of a bridge abutment using FEM

Directory of Open Access Journals (Sweden)

Wymysłowski Michał

2016-06-01

Full Text Available Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Treatment of ectopically erupting maxillary permanent first molars with a distal extended stainless steel crown.

Science.gov (United States)

Roberts, M W

1986-01-01

The exaggerated mesial eruption of the permanent first molar can result in the tooth becoming impacted, or the premature atypical resorption and exfoliation of the primary molar, with a resultant loss of space. A stainless steel crown with a distal guide plane was placed on a primary molar to correct the aberrant eruption angle of the permanent tooth. This procedure can be used successfully for both partially and totally tissue-impacted teeth, and is described in this report.

Arch-Axis Coefficient Optimization of Long-Span Deck-Type Concrete-Filled Steel Tubular Arch Bridge

Science.gov (United States)

Liu, Q. J.; Wan, S.; Liu, H. C.

2017-11-01

This paper is based on Nanpuxi super major bridge which is under construction and starts from Wencheng Zhejiang province to Taishun highway. A finite element model of the whole bridge is constructed using Midas Civil finite element software. The most adverse load combination in the specification is taken into consideration to determine the method of calculating the arch-axis coefficient of long-span deck-type concrete-filled steel tubular arch bridge. By doing this, this paper aims at providing references for similar engineering projects.

Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports.

Science.gov (United States)

2014-05-01

Different problems in straight skewed steel I-girder bridges are often associated with the methods used for detailing the cross-frames. Use of theoretical terms to describe these detailing methods and absence of complete and simplified design approac...

Magnetic-based NDE of steel in prestressed and post-tensioned concrete bridges

Science.gov (United States)

Ghorbanpoor, Al

1998-03-01

This paper addresses a study, funded by the Federal Highway Administration (FHWA), the U.S. Department of Transportation (DOT), that is currently underway at the University of Wisconsin-Milwaukee. The objective of the study is to develop an automated non-destructive testing system based on the magnetic flux leakage principle that would allow assessment of the condition of reinforcing and prestressing steels in concrete bridge components. Corrosion or cracking of steel within concrete members will be detected and evaluated. The system will be used as a self clamping and moving sensing device that can be installed on a concrete girder. Data from the sensing device is transmitted via a wireless communication system to data recording/analysis equipment on the ground. The sensing device may also be operated manually to allow inspection of local areas such as the end bearing or cable anchorage locations in cable bridges. Through performing a correlation analysis of recorded data, an assessment of the condition of the member under test is made. Reference data base for the correlation analysis is established through laboratory and field testing with known conditions.

Suppression of deicing salt corrosion of weathering steel bridges by washing

International Nuclear Information System (INIS)

Hara, Shuichi; Miura, Masazumi; Uchiumi, Yasushi; Fujiwara, Toshiaki; Yamamoto, Masataka

2005-01-01

To elucidate the influences of deicing salts and high pressure (2-4 MPa) washing on the characteristics of the rust formed on weathering steel bridges, washing experiments have been carried out for three years. The rust was characterized by means of ion chromatography, X-ray diffraction and adsorption of N 2 . The rust thickness was measured, and also the rust weight per unit area of the steel surface was measured. It was found that water-soluble chloride accelerated the rate of corrosion because the rust particles grow by the chloride ions and micro-pore structure of the rust appeared by the chloride ions. Washing with water suppressed corrosion owing to the disappearance of chloride ions

Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

Assessment of exposure pathways connected with construction and operation of concrete bridge reinforced with very low level radioactive steel

International Nuclear Information System (INIS)

Panik, M.; Necas, V.

2012-01-01

Large amount of low level radioactive material arises during decommissioning of nuclear power plants. Material mostly comprises metal scrap and concrete ruble. Paper deals with recycling and reuse of metal scrap and its utilization as part of reinforcement of concrete bridges under the conditional release concept. Radiation exposure originating in very low level reinforcement steel consists of several exposure pathways. Short-term radiation impact is represented mostly by external exposure pathway and it is relevant to the construction workers and users of the bridge. Long-term radiation impacts on inhabitants living near finished bridge and it is divided into inhalation and ingestion of radionuclides-internal exposure pathways. Radiation impact caused by utilization of very low level radioactive waste was calculated using simulation software VISIPLAN 3D ALARA and GOLDSIM. Results of calculations provide fair summary of possibilities of utilization of conditionally released steel as reinforcement of concrete bridges. (Authors)

Multi-parameters sensitivity analysis of natural vibration modal for steel arch bridge

Directory of Open Access Journals (Sweden)

WANG Ying

2014-02-01

Full Text Available Because of the vehicle loads and environmental factors,the behaviors of bridge structure in service is becoming deterioration.The modal parameters are important indexes of structure,so sensitivity analysis of natural vibration is an important way to evaluate the behavior of bridge structure.In this paper,using the finite element software Ansys,calculation model of a steel arch bridge was built,and the natural vibration modals were obtained.In order to compare the different sensitivity of material parameters which may affect the natural vibration modal,5 factors were chosen to perform the calculation.The results indicated that different 5 factors had different sensitivity.The leading factor was elastic modulus of arch rib,and the elastic modulus of suspender had little effect to the sensitivity.Another argument was the opposite sensitivity effect happened between the elastic modulus and density of the material.

Evaluation of external exposure during building and operation of concrete bridges constructions that reuse the conditionally released steels - 59120

International Nuclear Information System (INIS)

Panik, Michal; Necas, Vladimir

2012-01-01

This paper presents ongoing results of the project presented at ICEM'10 [1] related to the topics of reusing the conditionally released materials from decommissioning. The subject of the reuse of conditionally released materials in this case is modeling of bridge constructions which reuse the conditionally released steel in the form of reinforcement bars for the concrete bridges. A general approach for the project was presented at ICEM'10. The activities of the project continue in evaluating the individual effective doses from the external exposure based on reused conditionally released steels separately for public and for professionals (the internal exposure will be evaluated in next stages of the project). Evaluated scenarios are related to critical groups of professionals constructing the bridges (worker's scenarios). The computer code VISIPLAN 3D ALARA 4.0 planning tool was used for the calculation of the individual effective dose for professionals. Various limits of the annual individual effective dose are used for the evaluation of calculation results. The aim of the ongoing modeling is to develop a set of data of maximal radioactivity concentration for individual radionuclides in the conditionally released steel used in the bridges model constructions in order not to exceed the limits for the individual effective dose. (authors)

Effect of magnetic properties of non-oriented electrical steel on torque characteristics of interior-permanent-magnet synchronous motor

Energy Technology Data Exchange (ETDEWEB)

Fujimura, Hiroshi [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., 1-8 Fuso-cho, Amagasaki 660-0891 (Japan)], E-mail: fujimura-hrs@sumitomometals.co.jp; Nitomi, Hirokatsu; Yashiki, Hiroyoshi [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., 1-8 Fuso-cho, Amagasaki 660-0891 (Japan)

2008-10-15

The torque characteristics of interior-permanent-magnet synchronous motor (IPMSM), in which core materials were our conventional non-oriented electrical steel 35SX250 and our developed steels 35SXH, 27SXH with high permeability, were measured by a pulse wave modulation (PWM) inverter control. The torque characteristics of the motor with developed steels were superior to that of conventional steel. The advantage of developed steels was remarkable in the high-toque region. Experimental torque separation using current phase control showed that reluctance torque was strongly affected by the magnetic properties of core materials. And we did magnetic field analysis of the motors by finite element method (FEM). The flux density in the teeth of the stator core was higher in the high permeability steels than that in the conventional steel under the same current condition. The developed steels are expected to be suited to the stator material of IPMSM used as drive motors for electric vehicles and compressor motors for air conditioner.

Effect of magnetic properties of non-oriented electrical steel on torque characteristics of interior-permanent-magnet synchronous motor

International Nuclear Information System (INIS)

Fujimura, Hiroshi; Nitomi, Hirokatsu; Yashiki, Hiroyoshi

2008-01-01

The torque characteristics of interior-permanent-magnet synchronous motor (IPMSM), in which core materials were our conventional non-oriented electrical steel 35SX250 and our developed steels 35SXH, 27SXH with high permeability, were measured by a pulse wave modulation (PWM) inverter control. The torque characteristics of the motor with developed steels were superior to that of conventional steel. The advantage of developed steels was remarkable in the high-toque region. Experimental torque separation using current phase control showed that reluctance torque was strongly affected by the magnetic properties of core materials. And we did magnetic field analysis of the motors by finite element method (FEM). The flux density in the teeth of the stator core was higher in the high permeability steels than that in the conventional steel under the same current condition. The developed steels are expected to be suited to the stator material of IPMSM used as drive motors for electric vehicles and compressor motors for air conditioner

Students design composite bridges

NARCIS (Netherlands)

Stark, J.W.B.; Galjaard, J.C.; Brekelmans, J.W.P.M.

1999-01-01

The paper gives an overview of recent research on steel-concrete composite bridge design by students of Delft University of Technology doing their master's thesis. Primary objective of this research was to find possibilities for application of steel-concrete composite bridges in the Netherlands,

Timber in Bridge Structures

OpenAIRE

Detkin, Viktoria

2016-01-01

The purpose of this final year project was to study the properties of timber as a structural material and the suitability of wood in load bearing members for bridge structures. For a case study, an existing timber bridge was selected. Due to its condition the bridge should be replaced. The design of a new bridge with steel beams holding a glulam deck was made. During the case study the replacement of steel beams by glulam timber ones was discussed. Some calculations were made in order to ...

A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets

Directory of Open Access Journals (Sweden)

Dongge Deng

2016-10-01

Full Text Available A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

Numerical simulations and experimental measurements of steel and ice impacts on concrete for acoustic interrogation of delaminations in bridge decks

Energy Technology Data Exchange (ETDEWEB)

Mazzeo, Brian A.; Patil, Anjali N.; Klis, Jeffrey M. [Brigham Young University, Department of Electrical and Computer Engineering, Provo, Utah, 84602 (United States); Hurd, Randy C.; Truscott, Tadd T. [Brigham Young University, Department of Mechanical Engineering, Provo, Utah, 84602 (United States); Guthrie, W. Spencer [Brigham Young University, Department of Civil and Environmental Engineering, Provo, Utah, 84602 (United States)

2014-02-18

Delaminations in bridge decks typically result from corrosion of the top mat of reinforcing steel, which leads to a localized separation of the concrete cover from the underlying concrete. Because delaminations cannot be detected using visual inspection, rapid, large-area interrogation methods are desired to characterize bridge decks without disruption to traffic, without the subjectivity inherent in existing methods, and with increased inspector safety. To this end, disposable impactors such as water droplets or ice chips can be dropped using automatic dispensers onto concrete surfaces to excite mechanical vibrations while acoustic responses can be recorded using air-coupled microphones. In this work, numerical simulations are used to characterize the flexural response of a model concrete bridge deck subject to both steel and ice impactors, and the results are compared with similar experiments performed in the laboratory on a partially delaminated concrete bridge deck slab. The simulations offer greater understanding of the kinetics of impacts and the responses of materials.

Experimental Investigation of Membrane Materials used in Multilayer Surfacing Systems for Orthotropic Steel Deck Bridges

NARCIS (Netherlands)

Tzimiris, G.

2017-01-01

In the Netherlands asphaltic surfacings on orthotropic steel deck bridges (OSDB) mostly consist of two structural layers. The upper layer consists of what is known as very open porous asphalt (ZOAB) for noise reduction. For the lower layer Guss Asphalt (GA) is used. Earlier investigations have shown

Fatigue assessment for selected connections of structural steel bridge components using the finite elements method

Science.gov (United States)

Śledziewski, Krzysztof

2018-01-01

Material fatigue it is one of the most frequent causes of steel bridge failures, particularly the bridges already existing. Thus, the procedure of fatigue life assessment is one of the most relevant procedures in a comprehensive assessment of load-carrying capacity and service life of the structure. A reliable assessment of the fatigue life is predominantly decisive for estimation of the remaining service life. Hitherto, calculation methods of welded joints took into account only stresses occurring in cross sections of whole elements and did not take into account stress concentration occurring in the vicinity of the weld, caused by geometrical aspects of the detail. At present, use of the Finite Element Analysis, makes possible looking for more accurate approach to the fatigue design of steel structures. The method of geometrical stresses is just such approach which is based on definition of stresses which take into account geometry of the detail. The study presents fatigue assessment of a representative type of welded joint in welded bridge structures. The testing covered longitudinal attachments. The main analyses were carried out on the basis of FEM and the method of local stresses, so-called "hot-spot" stresses. The obtained values of stresses were compared with the values obtained in accordance with the method of nominal stress.

Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere

Science.gov (United States)

Li, Dong-liang; Fu, Gui-qin; Zhu, Miao-yong; Li, Qing; Yin, Cheng-xiang

2018-03-01

The corrosion resistance of weathering bridge steels containing conventional contents of Ni (0.20wt%, 0.42wt%, 1.50wt%) and a higher content of Ni (3.55wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low (≤0.42wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher ( 3.55wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe2O2 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42wt% to 1.50wt%, the corrosion resistance of the bridge steel increased only slightly.

Numerical Simulation of Hysteretic Live Load Effect in a Soil-Steel Bridge

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Sobótka Maciej

2014-03-01

Full Text Available The paper presents numerical simulation of hysteretic live load effect in a soil-steel bridge. The effect was originally identified experimentally by Machelski [1], [2]. The truck was crossing the bridge one way and the other in the full-scale test performed. At the same time, displacements and stress in the shell were measured. The major conclusion from the research was that the measured quantities formed hysteretic loops. A numerical simulation of that effect is addressed in the present work. The analysis was performed using Flac finite difference code. The methodology of solving the mechanical problems implemented in Flac enables us to solve the problem concerning a sequence of load and non-linear mechanical behaviour of the structure. The numerical model incorporates linear elastic constitutive relations for the soil backfill, for the steel shell and the sheet piles, being a flexible substructure for the shell. Contact zone between the shell and the soil backfill is assumed to reflect elastic-plastic constitutive model. Maximum shear stress in contact zone is limited by the Coulomb condition. The plastic flow rule is described by dilation angle ψ = 0. The obtained results of numerical analysis are in fair agreement with the experimental evidence. The primary finding from the performed simulation is that the slip in the interface can be considered an explanation of the hysteresis occurrence in the charts of displacement and stress in the shell.

Comprehensive evaluation of fracture critical bridges.

Science.gov (United States)

2014-02-01

Two-girder steel bridges are classified as fracture critical bridges based on the definition given in the AASHTO LRFD Bridge Design Specifications. In a fracture critical bridge a failure of a tension member leads to collapse of the bridge. However, ...

AE characteristic for monitoring of fatigue crack in steel bridge members

Science.gov (United States)

Yoon, Dong-Jin; Jung, Juong-Chae; Park, Philip; Lee, Seung-Seok

2000-06-01

Acoustic emission technique was employed for the monitoring of crack activity in both steel bridge members and laboratory specimen. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity as well as conventional AE parameter analysis was discussed. A field test was also conducted on a railway bridge, which contain several fatigue cracks. Crack activities were investigated while in service with strain measurement. From the results, in the laboratory tests, the features of three parameters such as the length of crack growth, the AE energy, and the cumulative AE events, showed the almost same trend in their increase as the number of fatigue cycle increased. From the comparisons of peak amplitude and AE energy with stress intensity factor, it was verified that the higher stress intensity factors generated AE signals with higher peak amplitude and a large number of AE counts. In the field test, real crack propagation signals were captured and the crack activity was verified in two cases.

X-ray diffraction analysis of rust layer on a weathering steel bridge with surface treatment using synchrotron radiation

International Nuclear Information System (INIS)

Yamashita, Masato; Hara, Shuichi; Kamimura, Takayuki; Miyuki, Hideaki; Sato, Masugu

2007-01-01

We have examined the structure of rust layer formed on a weathering steel bridge, to which the surface treatment, employing the effect of Cr 2 (SO 4 ) 3 sophisticatedly designed to form the protective goethite (α-FeOOH) rust layer which contains a certain amount of Cr, Cr-goethite, was applied in 1996, using X-ray diffraction at SPring-8 synchrotron radiation facility. It was shown that the formation of α-FeOOH was promoted and/or crystal growth of γ-FeOOH was suppressed by the surface treatment. The increase in the protective ability index (PAI) of the rust layer indicates that the protective goethite was predominantly formed under the effect of the surface treatment. In conclusion, it can be said that the surface treatment worked well to promote the formation of the protective goethite rust layer on the weathering steel bridge during the 10-year exposure. (author)

APPLICATION OF STEEL PIPE PILE LOADING TESTS TO DESIGN VERIFICATION OF FOUNDATION OF THE TOKYO GATE BRIDGE

Science.gov (United States)

Saitou, Yutaka; Kikuchi, Yoshiaki; Kusakabe, Osamu; Kiyomiya, Osamu; Yoneyama, Haruo; Kawakami, Taiji

Steel sheet pipe pile foundations with large diameter steel pipe sheet pile were used for the foundation of the main pier of the Tokyo Gateway bridge. However, as for the large diameter steel pipe pile, the bearing mechanism including a pile tip plugging effect is still unclear due to lack of the practical examinations even though loading tests are performed on Trans-Tokyo Bay Highway. In the light of the foregoing problems, static pile loading tests both vertical and horizontal directions, a dynamic loading test, and cone penetration tests we re conducted for determining proper design parameters of the ground for the foundations. Design parameters were determined rationally based on the tests results. Rational design verification was obtained from this research.

Optimum design of large span concrete filled steel tubular arch bridge based on static, stability and modal analysis

Institute of Scientific and Technical Information of China (English)

赵长军; 胡隽; 徐兴

2002-01-01

A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant.

Steel bridges structural health monitoring based on operational modal analysis accommodating evaluation of uncertainty

Directory of Open Access Journals (Sweden)

Saeid Jahan

2017-11-01

Full Text Available Structural damage detection is based on that the dynamic response of structure will change because of damage. Hence, it is possible to estimate the location and severity of damage leads to changes in the dynamic response before and after the damage. In this study, the genetic fuzzy system has been used for bridge structural health monitoring. A key objective of using genetic algorithms is to automate the design of fuzzy systems. This method is used for damage detection of a single span railway bridge with steel girders and a concrete bridge. For studying damage detection, the numerical models of these two bridges are built with the measured dynamic characteristics. A three-dimensional finite element model and a single two-dimensional girders model of the bridge have been constructed to study usefulness of the genetic fuzzy system for damage detection and the effectiveness of modeling. After analysis to control the uncertainties, the measured frequencies are contaminated with some noise and the effect of that on the achievement of damage detection method is evaluated. The present study has shown that the natural frequency has appropriate sensitivity to different damage scenarios in the structure. In addition, the natural frequency in comparison with other modal parameters, is less affected by random noise. Increasing the number of measurement modes and using torsional modes, will lead to an accurate damage diagnosis even in symmetrical structures.

An Automated Sensing System for Steel Bridge Inspection Using GMR Sensor Array and Magnetic Wheels of Climbing Robot

Directory of Open Access Journals (Sweden)

Rui Wang

2016-01-01

Full Text Available Corrosion is one of the main causes of deterioration of steel bridges. It may cause metal loss and fatigue cracks in the steel components, which would lead to the collapse of steel bridges. This paper presents an automated sensing system to detect corrosion, crack, and other kinds of defects using a GMR (Giant Magnetoresistance sensor array. Defects will change the relative permeability and electrical conductivity of the material. As a result, magnetic field density generated by ferromagnetic material and the magnetic wheels will be changed. The defects are able to be detected by using GMR sensor array to measure the changes of magnetic flux density. In this study, magnetic wheels are used not only as the adhesion device of the robot, but also as an excitation source to provide the exciting magnetic field for the sensing system. Furthermore, compared to the eddy current method and the MFL (magnetic flux leakage method, this sensing system suppresses the noise from lift-off value fluctuation by measuring the vertical component of induced magnetic field that is perpendicular to the surface of the specimen in the corrosion inspection. Simulations and experimental results validated the feasibility of the system for the automated defect inspection.

The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor

Directory of Open Access Journals (Sweden)

Hong Zhang

2016-09-01

Full Text Available This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obtained from magnetic sensor-based measurement and numerical calculation, it is shown that the curves of tangential magnetic field at different lift-off height all intersect near the edge of the steel corrosion zone. The result indicates that the intersection of magnetic field curves can be used to detect and evaluate the range of the inner steel corrosion in engineering structures. The findings of this work propose a new and effective non-destructive test method for steel corrosion, and therefore enlarge the application of the micro-magnetic sensor.

Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading : Arcan Test Study and Numerical Modeling

NARCIS (Netherlands)

Jiang, X.; Qiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2016-01-01

The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress,

Dynamic Response of a Long-Span Concrete-Filled Steel Tube Tied Arch Bridge and the Riding Comfort of Monorail Trains

Directory of Open Access Journals (Sweden)

Hongye Gou

2018-04-01

Full Text Available In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train–bridge system is established to investigate the dynamic behaviors of the bridge under moving trains. A refined three-dimensional finite element model is built for the bridge and a 15 degrees-of-freedom vehicle model is presented for the train. The numerical model is validated using in-situ test results and then used to analyze the dynamic displacement and acceleration of the bridge and the trains on the bridge. Based on the simulation results, the impact factor of the bridge is investigated and the riding comfort of the trains is evaluated. The investigation results show that the impact factor of vehicle loads reaches the maximum value when the resonance of the bridge is induced by the moving vehicles. The effect of train braking predominates the longitudinal vibration of the bridge but is negligible in the transverse and vertical directions. The vehicle speed is the dominating factor for the riding comfort of the train.

Modal analysis of cable-stayed UHPC bridge

Directory of Open Access Journals (Sweden)

Tej Petr

2017-01-01

Full Text Available This paper deals with the dynamic analysis of cable-stayed UHPC bridge over the Vltava river near town Melnik in Czech Republic, Europe. Bridge serves for pedestrians and cyclists. This work aims to familiarize the reader with dynamic calculations carried out and the results obtained, describing the dynamic properties of proposed bridge. The construction of bridge is designed as a cable-stayed structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tonnes. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings.

Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

Directory of Open Access Journals (Sweden)

Kittisak Kuntiyawichai

2014-01-01

Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

Evaluation of stresses generated in steel finger joint of bridge by X-ray stress measurement

International Nuclear Information System (INIS)

Kohri, Ami; Kawano, Yutaka; Nishido, Takayuki

2017-01-01

In a steel bridge, the evaluation of the stress generated in the finger joint without a gap to absorb temperature change can be an index when evaluating the remaining life. This study chose as the object the finger joint of a diagonal bridge, where the generated stress state is considered to be more complicated, prepared a finger joint test specimen that simulated an actual part, and performed a load test. For judgment, FEM analysis, non-destructive X-ray stress measurement, and measurement of the generated stress using strain gauge were applied. Compared with the FEM analysis results, the difference in the stress value was generated due to the difference in the contact state, but the trends of the stress distribution were equivalent. In addition, the same measurement value as the strain gauge was obtained, and the validity of the X-ray stress measurement method was confirmed. As a result, it was found that the stress measurement method by X-ray is effective for measuring the generated stress including the residual stress of the finger joint without gap at a bridge. (A.O.)

Field application of a cable NDT system for cable-stayed bridge using MFL sensors integrated

Energy Technology Data Exchange (ETDEWEB)

Kim, Ju Won; Choi, Jun Sung; Park, Seung Hee [Sungkyunkwan University, Seoul (Korea, Republic of); Lee, Eun Chan [Korea Maintance Co., Ltd., Seoul (Korea, Republic of)

2014-02-15

In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

Field application of a cable NDT system for cable-stayed bridge using MFL sensors integrated

International Nuclear Information System (INIS)

Kim, Ju Won; Choi, Jun Sung; Park, Seung Hee; Lee, Eun Chan

2014-01-01

In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

CALCULATION OF INDUCTANCE OF THE INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR

Directory of Open Access Journals (Sweden)

Phyong Le Ngo

2017-01-01

Full Text Available Interior permanent magnet synchronous motor (IPMSM refers to salient-pole synchronous motors, characterized by inequality of inductances of longitudinal (d and transverse (q axes. Electromagnetic torque of IPMSM consists of two components: active torque and reactive torque; the latter depends on inductances of d and q axes. An analytical method to calculate own inductances and mutual inductances of a three-phase IPMSM is presented. Distributed windings of the stator are substituted by equivalent sine distributed windings. An interior permanent magnets rotor is substituted by an equivalent salient-pole rotor. Sections of a magnetic circuit comprising interior permanent magnets, air barriers and steel bridges are substituted by equivalent air-gap. The expressions of the magnetic induction created by current of the stator windings at each point of the air gap as well as of magnetic flux linkage of the stator windings have been obtained. The equations of the self-inductances of phases A, B, C, and of inductance of mutual induction are determined from magnetic flux linkage. The inductance of the d and q axes have been obtained as a result of transformation of the axes abc–dq. The results obtained with the use of the proposed analytical method and the finite element method are presented in the form of a graph; the calculations that have been obtained by these two methods were compared. 

Static and Dynamic Mechanical Properties of Long-Span Cable-Stayed Bridges Using CFRP Cables

Directory of Open Access Journals (Sweden)

Mei Kuihua

2017-01-01

Full Text Available The elastic modulus and deadweight of carbon fiber-reinforced polymer (CFRP cables are different from those of steel cables. Thus, the static and dynamic behaviors of cable-stayed bridges using CFRP cables are different from those of cable-stayed bridges using steel cables. The static and dynamic performances of the two kinds of bridges with a span of 1000 m were studied using the numerical method. The effects of geometric nonlinear factors on static performance of the two kinds of cable-stayed bridges were analyzed. The live load effects and temperature effects of the two cable-stayed bridges were also analyzed. The influences of design parameters, including different structural systems, the numbers of auxiliary piers, and the space arrangement types of cable, on the dynamic performance of the cable-stayed bridge using CFRP cables were also studied. Results demonstrate that sag effect of the CFRP cable is much smaller than that of steel cable. The temperature effects of CFRP cable-stayed bridge are less than those of steel cable-stayed bridge. The vertical bending natural vibration frequency of the CFRP cable-stayed bridge is generally lower than that of steel cable-stayed bridge, whereas the torsional natural vibration frequency of the former is higher than that of the latter.

75 FR 62181 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

Science.gov (United States)

2010-10-07

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, HIBT-30, (202) 366-1575, or Mr. Thomas Everett, Office of Bridge Technology, HIBT-30, (202) 366-4675, Federal Highway Administration, 1200 New... is categorized by the following material types, which are identified in the NBI: steel, concrete, pre...

77 FR 53251 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

Science.gov (United States)

2012-08-31

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, (202) 366-1575, or via email at [email protected] or Mr. Thomas Everett, Office of Bridge Technology, (202) 366-4675, or via email at thomas... the NBI: steel, concrete, pre-stressed concrete, and other. The category ``other'' includes wood...

76 FR 55160 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

Science.gov (United States)

2011-09-06

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, HIBT-30, (202) 366-1575, or Mr. Thomas Everett, Office of Bridge Technology, HIBT-30, (202) 366-4675, Federal Highway Administration, 1200 New... is categorized by the following material types, which are identified in the NBI: steel, concrete, pre...

Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

International Nuclear Information System (INIS)

An, Yun-Kyu; Song, Homin; Sohn, Hoon

2014-01-01

This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge. (paper)

Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

Directory of Open Access Journals (Sweden)

Lingyu Yu

2012-01-01

Full Text Available Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS. After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated through both static and compact tension fatigue tests. With the use of coaxial cable wiring, PWAS AE signal quality has been improved. The active ultrasonic inspection is conducted by the damage index and wave imaging approach. The results in the paper show that such an integration of passive acoustic emission detection with active ultrasonic sensing is a technological leap forward from the current practice of periodic and subjective visual inspection and bridge management based primarily on history of past performance.

Technical features of steel structure construction by Kawasaki Steel; Kawasaki Seitetsu no kokozo gijutsu no tokucho

Energy Technology Data Exchange (ETDEWEB)

Kaneko, T.; Urata, I.; Okata, S. [Kawasaki Steel Corp., Tokyo (Japan)

1996-03-01

In the steel structure technology of Kawasaki Steel, the joint technique (e.g., welding) is added to them while developing or improving the products that meet the social needs as a material supplier. Moreover, the execution technique that manufactures materials or constructs them as an integrated structure, the structural analysis that conforms to the function and application of a structure, and the design technique on dynamic properties or durability such as earthquake resistance, fatigue, and corrosion resistance are synthetically expanded for engineering. In this paper, a building steel frame, non-residence building, bridge, and harbor structure as steel structure in the building and construction fields were described for each structure genre. The structural technology of a building steel frame is summarized to the products of pillar materials. An earthquake brace, using a dead soft steel, with high earthquake energy absorption capability and a damping wall were also developed. The design and execution technique of a large roof was systematized. The exchange technique of a road bridge RC floor and the technique of an unstiffened suspension bridge for pipeline were developed. A new technique was also developed for a suspension monorail track and offshore structure. 30 refs., 5 figs.

Evaluation of Radiation Exposure during Construction and Operation of Concrete Bridge Reinforced with Very Low Level Radioactive Steel

International Nuclear Information System (INIS)

Panik, M.; Necas, V.

2012-01-01

A lot of nuclear power plants are approaching the end of their lifetime and they will be phased out. Decommissioning of these nuclear power plants involve complete dismantling of technologies and demolition of buildings. During this process it is produced plenty of waste material of different categories. Significant portion of decommissioning materials comprise radionuclides what is caused by contamination and activation processes mostly from the operational period of nuclear power plant. Attention in this paper is paid to waste steel from the decommissioning of nuclear power plants with the specific activity just slightly exceeding legislation limits for the unconditional release into the environment. From the traditional point of view this material should be treated, conditioned and disposed on the radioactive waste repository. Second possibility is to release this material conditionally and reuse it in chosen industrial application. Very low level radioactive steel scrap should be melted and melting products should be processed into products that can be applied in industry. First option requires considerable financial investment, human resources and repository capacity. Second option saves some financial funds and it enables to reuse and save potentially valuable material for the future. Paper comprises evaluation of external and internal exposure during construction and operation of concrete bridges that utilize very low level radioactive steel as part of their reinforcement. Two models of representative concrete bridges were created. External gamma exposure and exposure from inhalation and ingestion of radionuclides were calculated using suitable computational tools. VISIPLAN 3D ALARA planning tool was chosen for the calculation of external gamma exposure. Software GOLDSIM enables to calculate transport of radionuclides initially contained in conditionally released reinforcement steel through subsoil and sequential exposure of people caused by inhalation of

Cluster analysis of stress corrosion mechanisms for steel wires used in bridge cables through acoustic emission particle swarm optimization.

Science.gov (United States)

Li, Dongsheng; Yang, Wei; Zhang, Wenyao

2017-05-01

Stress corrosion is the major failure type of bridge cable damage. The acoustic emission (AE) technique was applied to monitor the stress corrosion process of steel wires used in bridge cable structures. The damage evolution of stress corrosion in bridge cables was obtained according to the AE characteristic parameter figure. A particle swarm optimization cluster method was developed to determine the relationship between the AE signal and stress corrosion mechanisms. Results indicate that the main AE sources of stress corrosion in bridge cables included four types: passive film breakdown and detachment of the corrosion product, crack initiation, crack extension, and cable fracture. By analyzing different types of clustering data, the mean value of each damage pattern's AE characteristic parameters was determined. Different corrosion damage source AE waveforms and the peak frequency were extracted. AE particle swarm optimization cluster analysis based on principal component analysis was also proposed. This method can completely distinguish the four types of damage sources and simplifies the determination of the evolution process of corrosion damage and broken wire signals. Copyright © 2017. Published by Elsevier B.V.

Performance evaluation of concrete bridge decks reinforced with MMFX and SSC rebars.

Science.gov (United States)

2006-01-01

This report investigates the performance of bridge decks reinforced with stainless steel clad (SSC) and micro-composite multistructural formable steel (MMFX) rebars. The two-span Galloway Road Bridge on route CR5218 over North Elkhorn Creek in Scott ...

Permanent multipole magnets with adjustable strength

International Nuclear Information System (INIS)

Halbach, K.

1983-01-01

Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrople will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented

Permanent multipole magnets with adjustable strength

International Nuclear Information System (INIS)

Halbach, K.

1983-03-01

Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrupole will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented

Fatigue analysis and life prediction of composite highway bridge decks under traffic loading

Directory of Open Access Journals (Sweden)

Fernando N. Leitão

Full Text Available Steel and composite (steel-concrete highway bridges are currently subjected to dynamic actions of variable magnitude due to convoy of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation on the bridge deck structure. Proper consideration of all of the aspects mentioned pointed our team to develop an analysis methodology with emphasis to evaluate the stresses through a dynamic analysis of highway bridge decks including the action of vehicles. The design codes recommend the application of the curves S-N associated to the Miner's damage rule to evaluate the fatigue and service life of steel and composite (steel-concrete bridges. In this work, the developed computational model adopted the usual mesh refinement techniques present in finite element method simulations implemented in the ANSYS program. The investigated highway bridge is constituted by four longitudinal composite girders and a concrete deck, spanning 40.0m by 13.5m. The analysis methodology and procedures presented in the design codes were applied to evaluate the fatigue of the bridge determining the service life of the structure. The main conclusions of this investigation focused on alerting structural engineers to the possible distortions, associated to the steel and composite bridge's service life when subjected to vehicle's dynamic actions.

Covered Bridge Security Manual

Science.gov (United States)

Brett Phares; Terry Wipf; Ryan Sievers; Travis Hosteng

2013-01-01

The design, construction, and use of covered timber bridges is all but a lost art in these days of pre-stressed concrete, high-performance steel, and the significant growth both in the volume and size of vehicles. Furthermore, many of the existing covered timber bridges are preserved only because of their status on the National Registry of Historic Places or the...

Nondestructive testing for bridge diagnosis

International Nuclear Information System (INIS)

Oshima, Toshiyuki; Mikami, Shuichi; Yamazaki, Tomoyuki

1997-01-01

There are many motivations for bridge diagnosis using Nondestructive testing (NDT) to monitor its integrity. The measured frequency and damping on real bridge are compared in one figure as a function of span length and general aspects are explained. These date were measured in every construction of bridges and applied to design new bridges. Ultrasonic testing is also well used for concrete and steel members mainly to detect internal damages or delaminations. Detail analysis on reflected waves gives us more accurate information about the defect. Experimental results are shown as examples in this paper.

Long-Term Effects of Super Heavy-Weight Vehicles on Bridges

OpenAIRE

Wood, Scott M.; Akinci, Necip Onder; Liu, Judy; Bowman, Mark D

2007-01-01

A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel br...

Advanced structural materials for the suspension bridge solution of the project to establish a permanent link over the strait of Gibraltar; Materiales estructurales para la solucion puente, relacionados con el proyecto de enlace fijo a traves del estrecho de Gibraltar

Energy Technology Data Exchange (ETDEWEB)

Galligo Esteve, J. M.

2015-07-01

In 1995, the Spanish-moroccan Mixed Committee for the Gibraltar Strait Fixed Link selected the excavated tunnel solution, as preferred to the suspension bridge one. This was based on detailed scientific and technical studies. Nonetheless, further geology studies on the tunnel layout have detected sections of difficult excavation, which would entail increases in the length, the term of execution and the cost of the tunnel. Taking this into account, and due to the important technology development in bridge construction that has taken place over the last 20 years, the paper presents a state-of-the-art of the most advanced structural materials (high performance concrete, ultra-high performance concrete, suspension cables, structural steel, reinforcing and prestressing steel, stainless steel) available for an eventual reconsideration of the suspension bridge solution for the Gibraltar Strait Fixed Link. (Author)

Modern permanent magnetic materials - preparation and properties

International Nuclear Information System (INIS)

Rodewald, W.

1989-01-01

First of all, the basic properties of the classical (steel, AlNiCo) permanent magnetic materials and the modern rare-earth (RE) permanent magnetic materials are compared. Since the properties of RE permanent magnets depend on the particular production process, the fundamentals of the main industrial processes (powder metallurgy, rapid-solidification technique) are described and the typical properties are explained. Furthermore the production processes in development such as mechanical alloying, melt spinning technique and extrusion upsetting are briefly outlined. For applying the permanent magnets, they have to be completely magnetized. The magnetization behaviour of the various RE permanent magnets is discussed by means of the internal demagnetization curve. Finally the various influences on the temperature stability of RE permanent magnets are compiled. (orig./MM) [de

Final Environmental Assessment, Horse Creek Bridge Replacement

Science.gov (United States)

2010-10-01

existing bridge pipes that have failed and replace the failed structure with a new, prefabricated pedestrian bridge within the original bridge footprint...vehicles, nor designed for support of standard passenger vehicle loads. The bridge would be a single prefabricated unit consisting of a steel grate...placed on new concrete abutments built on the existing foundations on the creek banks, and put in place by a crane operating from the vehicle parking

Ældre betonbroers bæreevne (Load bearing capacity of old concrete bridges)

DEFF Research Database (Denmark)

Nielsen, Anders

1999-01-01

Two old bridges have been analysed in connection with their demolition. The first one is a pedestrian bridge, the Gefion bridge, from 1894. This is the first bridge of reinforced concrete in Denmark. Here the creep in the concrete severely have changed the way in which the load on the bridge was ...... was carried. - The other is a motor way bridge from 1939, which were reinforced 1991 with external steel plates on the areas of shear on the beams. Four beams were carried to our laboratory and load tested. The steel plates have doubled the load bearing capacity of the beams....

Seismic evaluation and retrofit of deteriorated concrete bridge components.

Science.gov (United States)

2013-06-01

Corrosion of steel bars in reinforced concrete structures is a major durability problem for bridges constructed in the New York State : (NYS). The heavy use of deicing salt compounds this problem. Corrosion of steel bars results in loss of steel cros...

Kawasaki Steel Giho, Vol. 27, No. 4, 1995. Special issue on steel structure

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

;Contents (Partial): Vertical Gust Prediction of Cable-Stayed Bridges in Yawed Wind; Design and Construction of a Super Platform Structure Made of Steel; Prefabricated Steel Deck of Battledeck Floor Type for Redecking; Aesthetic Design of Structures; and Lift-up Construction Method for Multi-layer Building.

Hybrid FRP-concrete bridge deck system final report II : long term performance of hybrid FRP-concrete bridge deck system.

Science.gov (United States)

2009-06-01

This report describes the investigation of the long term structural performance of a : hybrid FRP-concrete (HFRPC) bridge deck on steel girders. The study aimed at : assessing three long term aspects pertaining to the HFRPC bridge deck: (1) creep : c...

Hybrid Discrete Element - Finite Element Simulation for Railway Bridge-Track Interaction

Science.gov (United States)

Kaewunruen, S.; Mirza, O.

2017-10-01

At the transition zone or sometimes called ‘bridge end’ or ‘bridge approach’, the stiffness difference between plain track and track over bridge often causes aggravated impact loading due to uneven train movement onto the area. The differential track settlement over the transition has been a classical problem in railway networks, especially for the aging rail infrastructures around the world. This problem is also additionally worsened by the fact that the construction practice over the area is difficult, resulting in a poor compaction of formation and subgrade. This paper presents an advanced hybrid simulation using coupled discrete elements and finite elements to investigate dynamic interaction at the transition zone. The goal is to evaluate the dynamic stresses and to better understand the impact dynamics redistribution at the bridge end. An existing bridge ‘Salt Pan Creek Railway Bridge’, located between Revesby and Kingsgrove, has been chosen for detailed investigation. The Salt Pan Bridge currently demonstrates crushing of the ballast causing significant deformation and damage. Thus, it’s imperative to assess the behaviours of the ballast under dynamic loads. This can be achieved by modelling the nonlinear interactions between the steel rail and sleeper, and sleeper to ballast. The continuum solid elements of track components have been modelled using finite element approach, while the granular media (i.e. ballast) have been simulated by discrete element method. The hybrid DE/FE model demonstrates that ballast experiences significant stresses at the contacts between the sleeper and concrete section. These overburden stress exists in the regions below the outer rails, identify fouling and permanent deformation of the ballast.

Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

Science.gov (United States)

Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

2015-09-01

In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

Prediction of welding shrinkage deformation of bridge steel box girder based on wavelet neural network

Science.gov (United States)

Tao, Yulong; Miao, Yunshui; Han, Jiaqi; Yan, Feiyun

2018-05-01

Aiming at the low accuracy of traditional forecasting methods such as linear regression method, this paper presents a prediction method for predicting the relationship between bridge steel box girder and its displacement with wavelet neural network. Compared with traditional forecasting methods, this scheme has better local characteristics and learning ability, which greatly improves the prediction ability of deformation. Through analysis of the instance and found that after compared with the traditional prediction method based on wavelet neural network, the rigid beam deformation prediction accuracy is higher, and is superior to the BP neural network prediction results, conform to the actual demand of engineering design.

Economical bridge solutions based on innovative composite dowels and integrated abutments ecobridge

CERN Document Server

Băncilă, Radu

2015-01-01

This book is an outcome of the research project “ECOBRIDGE – Demonstration of ECOnomical BRIDGE solutions based on innovative composite dowels and integrated abutments – RFCS – CT 2010-00024”, which has been co-funded by the Research Fund for Coal and Steel (R.F.C.S.) of the European Community. The main topics of the book are the following: design of integral bridges, innovative composite dowels for the shear transmission, construction of bridges, structural analysis of bridges and monitoring. The book joins the technical experience and the contributions of the involved research partners. The technical content of all the papers is present-day in the field of the design, construction and monitoring of innovative composite bridges. The efficient design and construction improve and consolidate the market position of steel construction and steel producing industry. In addition, the advanced forms of construction are contributing to savings in material and energy consumption for the structure during prod...

Impact on the environment from steel bridge paint deterioration using lead isotopic tracing, paint compositions and soil deconstruction

Energy Technology Data Exchange (ETDEWEB)

Gulson, Brian, E-mail: brian.gulson@mq.edu.au [Department of Environmental Science, Macquarie University, Sydney, NSW 2109 (Australia); CSIRO Energy Flagship, North Ryde, NSW 2113 (Australia); Chiaradia, Massimo [Department of Mineralogy, University of Geneva, Geneva (Switzerland); Davis, Jeffrey [CSIRO Energy Flagship, North Ryde, NSW 2113 (Australia); O' Connor, Gary [Queensland Department of Environment & Heritage Protection, Brisbane, QLD 4000 (Australia)

2016-04-15

Deterioration and repair of lead paint on steel structures can result in contamination of the ambient environment but other sources of lead such as from past use of leaded paint and gasoline and industrial activities can also contribute to the contamination. Using a combination of high precision lead isotopic tracing, detailed paint examination, including with scanning electron microscopy, and soil deconstruction we have compared paint on a steel bridge and bulk soil and lead-rich particles separated from soil. The majority of Pb found in the paint derives from Australian sources but some also has a probable US origin. The isotopic data for the bulk soils and selected particles lie on a mixing line with end members the geologically ancient Broken Hill lead and possible European lead which is suggested to be derived from old lead paint and industrial activities. Data for gasoline-derived particulates lie on this array and probably contribute to soil Pb. Although paint from the bridge can be a source of lead in the soils, isotopic tracing, paint morphology and mineralogical identification indicate that other sources, including from paint, gasoline and industrial activities, are contributing factors to the lead burden. Even though physical characteristics and elemental composition are the same in some particles, the isotopic signatures demonstrate that the sources are different. Plots using {sup 206}Pb/{sup 208}Pb vs {sup 206}Pb/{sup 207}Pb ratios, the common representation these days, do not allow for source discrimination in this investigation. - Highlights: • Soil Pb values up to 1200 mg/kg below Pb painted bridge • Microscopy & SEM characterised up to 6 different paint layers. • Isotopes identified different sources of Pb including paint and gasoline. • Multiple methods provide definitive answers.

Overview of the National Timber Bridge Inspection Study

Science.gov (United States)

James P. Wacker; Brian K. Brashaw; Frank Jalinoos

2013-01-01

As many engineers begin to implement life cycle cost analyses within the preliminary bridge design phase, there is a significant need for more reliable data on the expected service life of highway bridges. Many claims are being made about the expected longevity of concrete and steel bridges, but few are based on actual performance data. Because engineers are least...

Experimental use of Line-X coated steel pipe piles, Clay Hill Bridge (#2157) replacement project over the Mousam River, Route 9/Western Avenue, Kennebunk, Maine.

Science.gov (United States)

2013-02-01

Steel pipe piles used by MaineDOT for bridge construction are typically coated with a fusion-bonded epoxy (FBE). FBE is a powder-based coating with properties similar to traditional : epoxies. Its name is derived from the process by which it adheres ...

Seismic Passive Control of Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

Hosam-Eddin M. Ali

1995-01-01

Full Text Available A three-dimensional modeling procedure is proposed for cable-stayed bridges with rubber, steel, and lead energy dissipation devices. The passive control technique is investigated by considering the response of bridge models with and without energy dissipation devices. The impact of various design parameters on the seismic response of current and future bridge designs is studied. Appropriate locations and properties of the passive devices can achieve better performance for cable-stayed bridges by balancing the significant reduction in earthquake-induced forces against tolerable displacements. Proper design of passive systems can help provide solutions for retro-fitting some existing bridges.

Fuzzy stochastic analysis of serviceability and ultimate limit states of two-span pedestrian steel bridge

Science.gov (United States)

Kala, Zdeněk; Sandovič, GiedrÄ--

2012-09-01

The paper deals with non-linear analysis of ultimate and serviceability limit states of two-span pedestrian steel bridge. The effects of random material and geometrical characteristics on limit states are analyzed. The Monte Carlo method was applied to stochastic analysis. For the serviceability limit state, also influence of fuzzy uncertainty of the limit deflection value on random characteristics of load capacity of variable action was studied. The results prove that, for the type of structure studied, the serviceability limit state is decisive from the point of view of design. The present paper opens a discussion on the use of stochastic analysis to verify the limit deflections given in the standards EUROCODES.

Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

Science.gov (United States)

Flaga, Kazimierz; Furtak, Kazimierz

2015-03-01

Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

Bridge and steel structures. History and vision on bridge erection; Kyoryo kokozobutsu. Kasetsu gijutsu no shorai

Energy Technology Data Exchange (ETDEWEB)

Mukai, S.; Hayashi, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1998-08-20

This paper describes the progress of bridge erection technology. It introduces the results of cable erection, rotated/extruded erection, and cantilever erection. The cable erection is a multi point suspension erection using cables. For the rotated/extruded erection, the monolithic construction is conducted on a working yard set in a right angle to the construction position, and the horizontal beams of the bridge piers (corbel girders) are constructed by the rotated method using a slewing base incorporated around the bridge piers at one side. For the construction of stiffening girders of Innoshima-ohashi Bridge of Honshu-Shikoku Joint Bridge in 1978, trussed face bar blocks were extruded from the main tower in order using a travel crane. For the suspension bridges and cable stayed bridges, main towers were erected using various types of cranes. The erection of Tamashima-ohashi Bridge with a weight of 500 ton using an offshore floating crane is introduced as a large block method. Analysis methods and measurement techniques at the site are used in order to analyze the shape in each step under the erection and to ensure the accurate final complete shape. Reduction of the construction cost, improvement of erection technology, and technology development for large-scale projects are subjects in the future. 22 refs., 8 figs., 1 tab.

High strength reinforcing steel bars : concrete shear friction interface : final report : Part A.

Science.gov (United States)

2017-03-01

High-strength steel (HSS) reinforcement, specifically ASTM A706 Grade 80 (550), is now permitted by the AASHTO LRFD Bridge Design Specifications for use in reinforced concrete bridge components in non-seismic regions. Using Grade 80 (550) steel reinf...

Development of eddy-current-free MR imaging system with 0.3-T permanent magnet

International Nuclear Information System (INIS)

Kuroda, M.; Takeuchi, H.; Nishimura, H.; Yanaka, S.; Takeshima, H.; Yoshino, H.; Miyamoto, T.; Sakurai, H.

1990-01-01

This paper reports on the eddy current induced by the magnetic gradient field which causes various problems associated with a permanent magnet, the permanent magnetic circuit with new pole pieces has been studied. The magnetic circuit was composed of a permanent magnet, a yoke, and pole pieces. The pole pieces were magnetically connected to the Nd-Fe-B permanent magnet. To study for eddy current, read-size magnetic circuits with pole pieces of various material, such as (a) steel, (b) divided steel, (c) toroidal-shaped silicon steel, and (d) composite material were assembled. The whole 0.3-T MR imaging system consists of only three units, Gantry with coach, MR unit, and operational console with image processor. We have evaluated the frequency characteristics, rise time, spatial homogeneity of magnetic field, and image quality with respect to real-size magnetic circuits with various pole pieces. We have obtained following order for frequency characteristics: (d), (c), (b), (a). We have also made an effort to adjust uniformity of magnetic field for magnetic circuits with toroidal-shaped silicon steel. We have obtained crisp and accurate images with use of the new pole pieces, without causing an eddy current. Especially, MR angio imaging, which is sensitive for eddy current, can be obtained with remarkable improvement

INVESTIGATION OF LAUNCHING PROCESS FOR STEEL REINFORCED CONCRETE FRAMEWORK OF LARGE BRIDGES

Directory of Open Access Journals (Sweden)

V. A. Grechukhin

2017-01-01

Full Text Available Bridges are considered as the most complicated, labour-consuming and expensive components in roadway network of the Republic of Belarus. So their construction and operation are to be carried out at high technological level. One of the modern industrial methods is a cyclic longitudinal launching of large frameworks which provide the possibility to reject usage of expensive auxiliary facilities and reduce a construction period. There are several variants of longitudinal launching according to shipping conditions and span length: without launching girder, with launching girder, with top strut-framed beam in the form of cable-stayed system, with strut-framed beam located under span. While using method for the cyclic longitudinal launching manufacturing process of span is concentrated on the shore. The main task of the investigations is to select economic, quick and technologically simple type of the cyclic longitudinal launching with minimum resource- and labour inputs. Span launching has been comparatively analyzed with temporary supports being specially constructed within the span and according to capital supports with the help of launching girder. Conclusions made on the basis of calculations for constructive elements of span according to bearing ability of element sections during launching and also during the process of reinforced concrete plate grouting and at the stage of operation have shown that span assembly with application of temporary supports does not reduce steel spread in comparison with the variant excluding them. Results of the conducted investigations have been approbated in cooperation with state enterprise “Belgiprodor” while designing a bridge across river Sozh.

The Corrosion of High Performance Steel in Adverse Environments

International Nuclear Information System (INIS)

Cook, Desmond C.

2005-01-01

The corrosion products that have formed on weathering steel bridges exposed to different weather conditions in the United States have been evaluated. They have been analyzed by spectroscopic techniques to determine the relationship between protective and non-protective rust coatings, and their relationship to the exposure conditions. Bridges constructed recently using High Performance Steel, as well as older bridges built with Type A588B weathering steel, were evaluated for corrosion performance of the rust coatings. In locations where the steel is subjected to regular wet-dry cycling, where the surface is wet for less than about 20% of the time, a protective patina starts to form after a few months exposure, and continues to an adherent, impervious coating after a decade. The protective patina is characterized by the formation of only goethite and lepidocrocite. The goethite makes up about 80% of the rust, and itself consists of a nanophase component, 40%, or infrequent drying cycles (regions close to waterways, fog or having high humidity), the weathering steel forms a rust coating that consists of a large amount of maghemite, and goethite that contains very little of the nanophase component. The rust coating ex-foliates from the steel and is not protective. Under exposure conditions in which chlorides are deposited onto the weathering steel surface (marine or de-icing salt locations), the protective patina also does not form. Instead, the rust coating consists of a large fraction of akaganeite that forms at the expense of the lepidocrocite and nanophase goethite. The bridges exposed to high chloride concentrations, 1.5 wt%, and therefore having no protective patina, have corrosion rates measured to be 6 times larger than expected for weathering steel with the protective patina

Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables

Directory of Open Access Journals (Sweden)

Xu Xie

2014-06-01

Full Text Available In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables.

Science.gov (United States)

Xie, Xu; Li, Xiaozhang; Shen, Yonggang

2014-06-23

In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

Load Distribution Factors for Composite Multicell Box Girder Bridges

Science.gov (United States)

Tiwari, Sanjay; Bhargava, Pradeep

2017-12-01

Cellular steel section composite with a concrete deck is one of the most suitable superstructures in resisting torsional and warping effects induced by highway loading. This type of structure has inherently created new design problems for engineers in estimating its load distribution when subjected to moving vehicles. Indian Codes of Practice does not provide any specific guidelines for the design of straight composite concrete deck-steel multi-cell bridges. To meet the practical requirements arising during the design process, a simple design method is needed for straight composite multi-cell bridges in the form of load distribution factors for moment and shear. This work presents load distribution characteristics of straight composite multi-cell box girder bridges under IRC trains of loads.

Verification of LRFD Bridge Design and Analysis Software for INDOT

OpenAIRE

Varma, Amit H.; Seo, Jungil

2009-01-01

NCHRP Process 12-50 was implemented to evaluate and verify composite steel I-girder bridge design software used commonly in Indiana. A test-bed of twenty one bridges was developed with the guidance from an Indiana Department of Transportation appointed research advisory panel (RAP). The test-bed included five simple-span and sixteen multi-span bridge superstructures. More than 80 parameters were required to define a bridge and they include bridge span, girder spacing, number of beams, section...

Study on Repaired Earthquake-Damaged Bridge Piers under Seismic Load

Directory of Open Access Journals (Sweden)

Jun Deng

2015-01-01

Full Text Available The concrete bridge pier damaged during earthquakes need be repaired to meet the design standards. Steel tube as a traditional material or FRP as a novel material has become popular to repair the damaged reinforced concrete (RC bridge piers. In this paper, experimental and finite element (FE studies are employed to analyze the confinement effectiveness of the different repair materials. The FE method was used to calculate the hysteretic behavior of three predamaged circle RC bridge piers repaired with steel tube, basalt fiber reinforced polymer (BFRP, and carbon fiber reinforced polymer (CFRP, respectively. Meanwhile, the repaired predamaged circle concrete bridge piers were tested by pseudo-static cyclic loading to study the seismic behavior and evaluate the confinement effectiveness of the different repair materials and techniques. The FE analysis and experimental results showed that the repaired piers had similar hysteretic curves with the original specimens and all the three repair techniques can restore the seismic performance of the earthquake-damaged piers. Steel tube jacketing can significantly improve the lateral stiffness and peak load of the damaged pier, while the BFRP and CFRP sheets cannot improve these properties due to their thin thickness.

Linear Cracking in Bridge Decks

Science.gov (United States)

2018-03-01

Concrete cracking in bridge decks remains an important issue relative to deck durability. Cracks can allow increased penetration of chlorides, which can result in premature corrosion of the reinforcing steel and subsequent spalling of the concrete de...

Environmental life cycle assessment of railway bridge materials using UHPFRC

Science.gov (United States)

Bizjak, Karmen Fifer; Šajna, Aljoša; Slanc, Katja; Knez, Friderik

2016-10-01

The railway infrastructure is a very important component of the world's total transportation network. Investment in its construction and maintenance is significant on a global scale. Previously published life cycle assessment (LCA) studies performed on road and rail systems very seldom included infrastructures in detail, mainly choosing to focus on vehicle manufacturing and fuel consumption. This article presents results from an environmental study for railway steel bridge materials for the demonstration case of the Buna Bridge in Croatia. The goal of these analyses was to compare two different types of remediation works for railway bridges with different materials and construction types. In the first part, the environmental impact of the classical concrete bridge construction was calculated, whereas in the second one, an alternative new solution, namely, the strengthening of the old steel bridge with ultra-high-performance fibre-reinforced concrete (UHPFRC) deck, was studied. The results of the LCA show that the new solution with UHPFRC deck gives much better environmental performance. Up to now, results of LCA of railway open lines, railway bridges and tunnels have been published, but detailed analyses of the new solution with UHPFRC deck above the old bridge have not previously been performed.

MASH Test 3-11 on the T131RC Bridge Rail

Science.gov (United States)

2012-10-01

Texas Department of Transportation (TxDOT) currently uses the TxDOT Type T101RC Bridge Rail, : a steel post and beam bridge rail anchored to the top of concrete curbs. The T101RC Bridge Rail is : 27 inches in height and can be anchored to the top of ...

FEATURES OF DESIGN OF TIED-ARCH BRIDGES WITH FLEXIBLE INCLINED SUSPENSION HANGERS

Directory of Open Access Journals (Sweden)

V. O. Samosvat

2017-10-01

Full Text Available Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigated a large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design.Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic.
A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with

Statistical determination of significant curved I-girder bridge seismic response parameters

Science.gov (United States)

Seo, Junwon

2013-06-01

Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.

Probabilistic and sensitivity analysis of Botlek Bridge structures

Directory of Open Access Journals (Sweden)

Králik Juraj

2017-01-01

Full Text Available This paper deals with the probabilistic and sensitivity analysis of the largest movable lift bridge of the world. The bridge system consists of six reinforced concrete pylons and two steel decks 4000 tons weight each connected through ropes with counterweights. The paper focuses the probabilistic and sensitivity analysis as the base of dynamic study in design process of the bridge. The results had a high importance for practical application and design of the bridge. The model and resistance uncertainties were taken into account in LHS simulation method.

Multidisciplinary health monitoring of a steel bridge deck structure

NARCIS (Netherlands)

Pahlavan, P.L.; Pijpers, R.J.M.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

2013-01-01

Fatigue cracks in orthotropic bridge decks are an important cause for the necessary renovation of existing bridges. Parallel utilization of various technologies based on different physical sensing principles can potentially maximize the efficiency of structural health monitoring (SHM) systems for

Management of early loss of first permanent molar: A new technique

Directory of Open Access Journals (Sweden)

B S Rajashekhara

2012-01-01

Full Text Available The loss of a permanent first molar in adolescent patient creates a need for early space maintenance and restoration of function. To ascertain function and esthetics, immediate treatments include interim restorative approaches. This paper describes a conservative, functional and cost-effective bridge as an interim restoration after the loss of permanent first molar in an early adolescent dentition.

The Vibration Based Fatigue Damage Assessment of Steel and Steel Fiber Reinforced Concrete (SFRC Composite Girder

Directory of Open Access Journals (Sweden)

Xu Chen

2015-01-01

Full Text Available The steel-concrete composite girder has been usually applied in the bridge and building structures, mostly consisting of concrete slab, steel girder, and shear connector. The current fatigue damage assessment for the composite girder is largely based on the strain values and concrete crack features, which is time consuming and not stable. Hence the vibration-based fatigue damage assessment has been considered in this study. In detail, a steel-steel fiber reinforced concrete (SFRC composite girder was tested. The steel fiber reinforced concrete is usually considered for dealing with the concrete cracks in engineering practice. The composite girder was 3.3m long and 0.45m high. The fatigue load and impact excitation were applied on the specimen sequentially. According to the test results, the concrete crack development and global stiffness degradation during the fatigue test were relatively slow due to the favourable performance of SFRC in tension. But on the other hand, the vibration features varied significantly during the fatigue damage development. Generally, it confirmed the feasibility of executing fatigue damage assessment of composite bridge based on vibration method.

Investigation Procedure of Magnetic Performances of NdFeB Permanent Magnets

DEFF Research Database (Denmark)

Calin, Marius-Daniel; Helerea, Elena; Ritchie, Ewen

2011-01-01

The permanent magnet applications based on carbon steel magnets, hard ferrites and AlNiCo magnets classes are renewed with new classes of advanced magnetic materials based on rare earth elements, the Sm-Co and NdFeB types. Performance increase of the hard magnetic materials and their use in speci......The permanent magnet applications based on carbon steel magnets, hard ferrites and AlNiCo magnets classes are renewed with new classes of advanced magnetic materials based on rare earth elements, the Sm-Co and NdFeB types. Performance increase of the hard magnetic materials and their use...... in specific applications impose also great advances in the field of magnetic measurement. New researches need to be validated in order to investigate the NdFeB permanent magnets performances, including their stability under different thermal operational regimes. In this paper a specific investigation...... procedure of magnetic performances of NdFeB permanent magnets in correlation with the range of operating temperature is proposed based on modern hysteresisgraph method and impulse magnetization technique....

PARAMETRIC STUDY OF SKEW ANGLE ON BOX GIRDER BRIDGE DECK

OpenAIRE

Shrikant D. Bobade *, Dr. Valsson Varghese

2016-01-01

Box girder bridge deck, is the most common type of bridges in world and India, it consists of several Slab or girders. The span in the direction of the roadway and connected across their tops and bottoms by a thin continuous structural stab, the longitudinal box girders can be made of steel or concrete. The Simple supported single span concrete bridge deck is presented in present study. Skewed bridges are suitable in highway design when the geometry of straight bridges is not possible. The sk...

Low Vertical Clearance Truss Bridges : Risk Assessment and Retrofit Mitigation Study

Science.gov (United States)

2017-11-10

The Washington State Department of Transportation (WSDOT) has over 60 steel truss bridges in its inventory with vertical clearances less than the minimum 16-6 required for new bridges. This study evaluates the risks of oversized vehicle impacts...

Finite element modelling for fatigue stress analysis of large suspension bridges

Science.gov (United States)

Chan, Tommy H. T.; Guo, L.; Li, Z. X.

2003-03-01

Fatigue is an important failure mode for large suspension bridges under traffic loadings. However, large suspension bridges have so many attributes that it is difficult to analyze their fatigue damage using experimental measurement methods. Numerical simulation is a feasible method of studying such fatigue damage. In British standards, the finite element method is recommended as a rigorous method for steel bridge fatigue analysis. This paper aims at developing a finite element (FE) model of a large suspension steel bridge for fatigue stress analysis. As a case study, a FE model of the Tsing Ma Bridge is presented. The verification of the model is carried out with the help of the measured bridge modal characteristics and the online data measured by the structural health monitoring system installed on the bridge. The results show that the constructed FE model is efficient for bridge dynamic analysis. Global structural analyses using the developed FE model are presented to determine the components of the nominal stress generated by railway loadings and some typical highway loadings. The critical locations in the bridge main span are also identified with the numerical results of the global FE stress analysis. Local stress analysis of a typical weld connection is carried out to obtain the hot-spot stresses in the region. These results provide a basis for evaluating fatigue damage and predicting the remaining life of the bridge.

Environmental life cycle assessment of railway bridge materials using UHPFRC

Directory of Open Access Journals (Sweden)

Bizjak Karmen Fifer

2016-10-01

Full Text Available The railway infrastructure is a very important component of the world’s total transportation network. Investment in its construction and maintenance is significant on a global scale. Previously published life cycle assessment (LCA studies performed on road and rail systems very seldom included infrastructures in detail, mainly choosing to focus on vehicle manufacturing and fuel consumption. This article presents results from an environmental study for railway steel bridge materials for the demonstration case of the Buna Bridge in Croatia. The goal of these analyses was to compare two different types of remediation works for railway bridges with different materials and construction types. In the first part, the environmental impact of the classical concrete bridge construction was calculated, whereas in the second one, an alternative new solution, namely, the strengthening of the old steel bridge with ultra-high-performance fibre-reinforced concrete (UHPFRC deck, was studied. The results of the LCA show that the new solution with UHPFRC deck gives much better environmental performance. Up to now, results of LCA of railway open lines, railway bridges and tunnels have been published, but detailed analyses of the new solution with UHPFRC deck above the old bridge have not previously been performed.

Evaluating the life cycle environmental impact of short span bridges

DEFF Research Database (Denmark)

Du, Guangli; Pettersson, Lars; Karoumi, Raid

2016-01-01

impact of the construction sector. Life cycle assessment (LCA) is a systematic method for assessing the environmental impact of products and systems, but its application in bridges is scarce. In Swede, most of the bridges are short spans and the type of concrete slab-frame bridge (CFB) accounts...... for a large share. Soil steel composite bridge (SSCB) is a functional equivalent solution for CFB. In order to mitigate the environmental burdens of short span bridges, this paper performed a comparative LCA study between these two types of bridge. The results indicate that the initial material consumption...

Influence of molybdenum content on transformation behavior of high performance bridge steel during continuous cooling

International Nuclear Information System (INIS)

Chen, Jun; Tang, Shuai; Liu, Zhenyu; Wang, Guodong

2013-01-01

Highlights: ► The bainite transformation field was refined. ► The empirical equation to estimate the GF s was established. ► Transformation behavior was studied with serially increasing Mo addition. ► The molybdenum content can be lowered as the cooling rate is increased. ► GF transformation field is also shifted to right by increasing Mo content. - Abstract: The continuous-cooling-transformation (CCT) diagrams of high performance bridge steel with different molybdenum content were plotted by means of a combined method of dilatometry and metallography. The results show that the molybdenum addition of 0.17 wt% does not noticeably alter the transformation behavior, whereas 0.38 wt% significantly. In addition, the molybdenum addition of 0.38 wt% completely eliminates the formation of polygonal ferrite (PF) and significantly lower the granular ferrite (GF) transformation starting temperatures throughout the range of cooling rates studied. At lower cooling rates, with the increase of the molybdenum content, the martensite/austenite (M/A) constituents are noticeably refined, whereas the effects are not obvious at higher cooling rates. Moreover, the molybdenum addition of 0.38 wt% can significantly increase the Vickers hardness, but the Vickers hardness increments (by comparison of Mo-0.17wt% steel and Mo-0.38wt% steel) are sharply reduced at the cooling rate of 30 °C/s, indicating that at higher cooling rate, the molybdenum usage can be saved and the higher strengthen can be also gained. It could be found the GF transformation starting temperature is linear with the cooling rate. The empirical equation was established to calculate GF transformation starting temperatures, and the calculated values are in good agreement with measured ones

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Science.gov (United States)

Szafran, J.; Kamiński, M.

2017-02-01

The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Directory of Open Access Journals (Sweden)

Szafran J.

2017-02-01

Full Text Available The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Dynamic response of a monorail steel bridge under a moving train

Science.gov (United States)

Lee, C. H.; Kawatani, M.; Kim, C. W.; Nishimura, N.; Kobayashi, Y.

2006-06-01

This study proposes a dynamic response analysis procedure for traffic-induced vibration of a monorail bridge and train. Each car in the monorail train is idealized as a dynamic system of 15-degrees-of-freedom. The governing equations of motion for a three-dimensional monorail bridge-train interaction system are derived using Lagrange's formulation for monorail trains, and a finite-element method for modal analysis of monorail bridges. Analytical results on dynamic response of the monorail train and bridge are compared with field-test data in order to verify the validity of the proposed analysis procedure, and a positive correlation is found. An interesting feature of the monorail bridge response is that sway motion is caused by torsional behavior resulting from eccentricity between the shear center of the bridge section and the train load.

Seismic Retrofitting of an Existing Steel Railway Bridge by Fluid Viscous Dampers

Science.gov (United States)

Gangopadhyay, Avijit; Ghosh, Aparna Dey

2016-09-01

There are over a lakh of bridges in the Indian Railways, many of which have become seismically deficient, either through aging or due to inadequate seismic design considerations. The extensive damage of bridges all over the world in recent earthquakes has propelled significant advancement in earthquake protection and retrofitting of bridges. Amongst various passive control systems that are reliable as well as cost-effective, Fluid Viscous Dampers (FVDs) are proving to be successful in bridge vibration control. Orificed FVDs, commercially available as Taylor Devices, have already been successfully installed in several bridges worldwide. However, there has been no such application or study related to Indian railway bridges. In this paper, an existing thirty years' old railway bridge in Jharkhand, India, has been analyzed in SAP2000v14 considering reduced stiffness and found deficient when subjected to spectrum-compatible accelerograms. Subsequent retrofitting of the bridge superstructure with FVDs has been carried out and the results indicate substantial reductions in the responses of the bridge deck.

Experimental studies of Steel Corrugated Constructions

Directory of Open Access Journals (Sweden)

Lazarev Yuriy

2016-01-01

Full Text Available The purpose of this particular article is to assess existing calculations of steel corrugated constructions. Steel Corrugated Construction is a perspective type of constructions, which is exhibiting numerous advantages in comparison with one that currently applied in automobile and railroad networks (reinforced concrete water-throughput pipes, reinforced concrete frame bridges. The evaluation of experimental data on models of constructions of this particular type has been carried out in order to improve calculations of Steel Corrugated Constructions.

On-site bridge inspection with partial CT by 3.95Mev X-band linac source

International Nuclear Information System (INIS)

Wu, Wenjing; Zhu, Haito; Jin, Ming

2012-01-01

Since more and more bridges built several decades ago in Japan have become aged and dangerous, the non-destructive evaluation of those bridges is really an urgent problem. CT system with portable 3.95MeV linacs for bridge inspection is considered to work on-site, considering the law of Japanese radiation protection allows using linacs up to 4MeV outside radiation controlled area. The system would confirm the internal steel situation of bridges and analyze structural strain and stress with 3D model built from sectional imaging to evaluate load-bearing performance. The reconstruction process of bridge imaging is based on partial scanned data because bridge shape confines possible scanning angle to smaller than 180deg and a few translations. A small concrete sample with internal steel bars and attachment accessories is scanned in laboratory as preliminary work. (author)

Probabilistic Model for Fatigue Crack Growth in Welded Bridge Details

DEFF Research Database (Denmark)

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard; Yalamas, Thierry

2013-01-01

In the present paper a probabilistic model for fatigue crack growth in welded steel details in road bridges is presented. The probabilistic model takes the influence of bending stresses in the joints into account. The bending stresses can either be introduced by e.g. misalignment or redistribution...... of stresses in the structure. The fatigue stress ranges are estimated from traffic measurements and a generic bridge model. Based on the probabilistic models for the resistance and load the reliability is estimated for a typical welded steel detail. The results show that large misalignments in the joints can...

Reducing Local Scouring at Bridge Piles Using Collars and Geobags

Directory of Open Access Journals (Sweden)

Shatirah Akib

2014-01-01

Full Text Available The present study examines the use of collars and geobags for reducing local scour around bridge piles. The efficiency of collars and geobags was studied experimentally. The data from the experiments were compared with data from earlier studies on the use of single piles with a collar and with a geobag. The results showed that using a combination of a steel collar and a geobag yields the most significant scour reduction for the front and rear piles, respectively. Moreover, the independent steel collar showed better efficiency than the independent geobag below the sediment level around the bridge piles.

Influence of Pavement on Fatigue Performance of Urban Steel Box Girder Deck

Directory of Open Access Journals (Sweden)

Zheng Zhongyue

2016-01-01

Full Text Available Based on spatial finite element analysis method, the Influence of pavement on fatigue performance of orthotropic steel deck was analyzed in terms of pavement system, asphalt pavement stiffness. The result shows that compared with asphalt pavement system, RPC pavement system can not only obviously improve the stress condition of steel bridge deck, but also significantly extend the fatigue life of steel bridge panel; Increasing the stiffness of pavement layer can obviously reduce the stress amplitude of fatigue details, especially for direct contact with the pavement.

Exodermic bridge deck performance evaluation.

Science.gov (United States)

2010-07-01

In 1998, the Wisconsin DOT completed a two"leaf bascule bridge in Green Bay with an exodermic deck system. The exodermic deck consisted of 4.5"in thick cast"in"place reinforced concrete supported by a 5.19"in tall unfilled steel grid. The concrete an...

Experimental assessment of an RFID-based crack sensor for steel structures

Science.gov (United States)

E Martínez-Castro, R.; Jang, S.; Nicholas, J.; Bansal, R.

2017-08-01

The use of welded steel cover plates had been a common design practice to increase beam section capacity in regions of high moment for decades. Many steel girder bridges with cover plates are still in service. Steel girder bridges are subject to cyclic loading, which can initiate crack formation at the toe of the weld and reduce beam capacity. Thus, timely detection of fatigue cracks is of utmost importance in steel girder bridge monitoring. To date, crack monitoring methods using in-house radio frequency identification (RFID)-based sensors have been developed to complement visual inspection and provide quantitative information of damage level. Offering similar properties at a reduced cost, commercial ultra-high frequency (UHF) passive RFID tags have been identified as a more financially viable option for pervasive crack monitoring using a dense array of sensors. This paper presents a study on damage sensitivity of low-cost commercial UHF RFID tags for crack detection and monitoring on metallic structures. Using backscatter power as a parameter for damage identification, a crack sensing system has been developed for single and multiple tag configurations for increased sensing pervasiveness. The effect on backscatter power of the existence and stage of crack propagation has been successfully characterized. For further automation of crack detection, a damage index based on the variation of backscatter power has also been established. The tested commercial RFID-based crack sensor contributes to the usage of this technology on steel girder bridges.

Structural evaluation of the John A. Roebling Suspension Bridge : element level analysis.

Science.gov (United States)

2008-07-01

The primary objective of the structural evaluation of the John A. Roebling Bridge is to determine the maximum allowable gross vehicle weight (GVW) that can be carried by the bridge deck structural elements such as the open steel grid deck, channels, ...

Remote monitoring of fatigue-sensitive details on bridges : [part I and II].

Science.gov (United States)

2015-03-01

Fatigue is one of the most critical problems for steel bridges as well as for any steel structures that needs : to be considered during design and operation. The objectives of this study are to explore monitoring : technologies, and to develop effect...

Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

1999-09-30

A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

Shear evaluation of tapered bridge girder panels with steel corrugated webs near the supports of continuous bridges

OpenAIRE

Zevallos, E.; Hassanein, M.F.; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique

2016-01-01

Because of public construction budgets were cut over the last few years, new bridge girders with corrugated webs to reduce the construction costs have become more widely studied and used. In spite that tapered bridge girders with corrugated webs (BGCWs) are used in modern bridges, their shear strength and behaviour rarely exists in literature. Based on available literature, the web of the linearly tapered BGCWs may be divided into three typologies with different structural response to shear f...

Teaching Steel Connections Using an Interactive Virtual Steel Sculpture

Science.gov (United States)

Moaveni, Saeed; Chou, Karen C.

2015-01-01

Steel connections play important roles in the integrity of a structure, and many structural failures are attributed to connection failures. Connections are the glue that holds a structure together. The failures of the Hartford Coliseum in 1977, the Hyatt Regency Hotel in Kansas City in 1980, and the I-35W Bridge in Minneapolis in 2007 are all…

Hollow-Core FRP–Concrete–Steel Bridge Columns under Torsional Loading

Directory of Open Access Journals (Sweden)

Sujith Anumolu

2017-11-01

Full Text Available This paper presents the behavior of hollow-core fiber-reinforced polymer–concrete–steel (HC-FCS columns under cyclic torsional loading combined with constant axial load. The HC-FCS consists of an outer fiber-reinforced polymer (FRP tube and an inner steel tube, with a concrete shell sandwiched between the two tubes. The FRP tube was stopped at the surface of the footing, and provided confinement to the concrete shell from the outer direction. The steel tube was embedded into the footing to a length of 1.8 times the diameter of the steel tube. The longitudinal and transversal reinforcements of the column were provided by the steel tube only. A large-scale HC-FCS column with a diameter of 24 in. (610 mm and applied load height of 96 in. (2438 mm with an aspect ratio of four was investigated during this study. The study revealed that the torsional behavior of the HC-FCS column mainly depended on the stiffness of the steel tube and the interactions among the column components (concrete shell, steel tube, and FRP tube. A brief comparison of torsional behavior was made between the conventional reinforced concrete columns and the HC-FCS column. The comparison illustrated that both column types showed high initial stiffness under torsional loading. However, the HC-FCS column maintained the torsion strength until a high twist angle, while the conventional reinforced concrete column did not.

Bridges analysis, design, structural health monitoring, and rehabilitation

CERN Document Server

Bakht, Baidar

2015-01-01

This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

Cable-stayed PC bridge with inclined main tower. Hachinohe port island bridge; Keisha shuto to yusuru 2 keikan renzoku PC shachokyo. Hachinoheko port island renrakykyo (kasho)

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, A. [Hachinohe Institute of Technology, Aomori (Japan)

1994-09-15

The design and construction of the inclined main bridge, which is being constructed at the mouth of the Hachinohe Harbor (in Japan), are outlined in this paper. This connecting bridge has an overall length of 265.56 m, and consists of the main bridge member of asymmetric 2 cable-stayed PC bridge and the 3 cable-stayed PC box member bridge. An asymmetric design was employed for the main bridge frame to ensure the access space for small ships passing between bridge girders, easy maintenance and service, improved economy, and excellent view. The main tower is a single-pillar reinforced concrete structure with an inclination of 15{degree} and 47 m in height. Forty-eight diagonal cables are arranged so that 12 cable trains are connected to the main tower on the right and left sides respectively, and the back-stay cable structure is used for each upper 3 cable trains to improve safety against the earthquake. The main beam is made by a prestressed concrete structure with inverse trapezoidal 3-chamber frame section. This structure is superior in increasing the safety against wind. Steel tube sheet-pile well is selected for the bridge pier base, and debris layer is selected as a support layer for the base. For the construction of the lower bridge section, sand conversion through predrilling of rubble-mound and debris layer was executed. The underwater non-separative concrete and embedded type frame are used around the bridge piers and its surrounding. For the construction of the upper bridge section, steel frames are used inside the main tower to ensure the construction precision. 7 figs.

The effect of span length and girder type on bridge costs

Directory of Open Access Journals (Sweden)

Batikha Mustafa

2017-01-01

Full Text Available Bridges have an important role in impacting the civilization, growth and economy of cities from ancient time until these days due to their function in reducing transportation cost and time. Therefore, development of bridges has been a knowledge domain in civil engineering studies in terms of their types and construction materials to confirm a reliable, safe, economic design and construction. Girder-bridge of concrete deck and I-beam girder has been used widely for short and medium span bridges because of ease and low-cost of fabrication. However, many theoretical and practical investigations are still undertaken regarding the type of beam girder; i.e steel composite or prestressed concrete. This paper evaluates the effect of bridge span and the type of girder on the capital cost and life cycle costs of bridges. Three types of girders were investigated in this research: steel composite, pre-tensioned pre-stressed concrete and post-tensioned pre-stressed concrete. The structural design was analyzed for 5 span lengths: 20, 25, 30, 35 and 40m. Then, the capital construction cost was accounted for 15 bridges according to each span and construction materials. Moreover, the maintenance required for 50 years of bridge life was evaluated and built up as whole life costs for each bridge. As a result of this study, the influence of both span length and type of girder on initial construction cost and maintenance whole life costs were assessed to support the decision makers and designers in the selection process for the optimum solution of girder bridges.

Instrumentation of the US grant bridge for monitoring of fabrication, erection, in-service behavior, and to support management, maintenance, and inspection.

Science.gov (United States)

2013-12-01

The replacement of the US Grant Bridge over the Ohio River in Portsmouth, OH, was initiated in : 2001 when the original bridge was closed and demolished, and its substitute opened in 2006. The : new design is a steel cable stay design with steel gird...

Stålplader gav dobbelt bæreevne (Steel plates doubled the load bearing capacity)

DEFF Research Database (Denmark)

Nielsen, Jan Broch

1999-01-01

Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams.......Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams....

Sensing and Rating of Vehicle–Railroad Bridge Collision

DEFF Research Database (Denmark)

Vemuganti, Shreya; Ozdagli, Ali I.; Liu, Bideng

2017-01-01

Overhead collisions of trucks with low-clearance railway bridges cause more than half of the railway traffic interruptions over bridges in the United States. Railroad owners are required to characterize the damage caused by such events and assess the safety of subsequent train crossings. However...... and remotely quantify damage. This research proposes an impact rating strategy based on the information that best describes the consequences of vehicle-railway bridge collisions. A series of representative impacts were simulated using numerical finite element models of a steel railway bridge. Railway owners...... provided information about the bridge and impact characterization based on railway industry experience. The resulting nonlinear dynamic responses were evaluated with the proposed rating strategy to assess the effect of these impacts. In addition, a neural network methodology was implemented on a simplified...

Recessed floating pier caps for highway bridges.

Science.gov (United States)

1973-01-01

Presented are alternate designs for two existing bridges in Virginia - one with steel beams and the other with prestressed concrete beams - whereby the pier caps are recessed within the depth of the longitudinal beams. The purpose of this recession i...

Evaluation of bridge deck with shrinkage-compensating concrete.

Science.gov (United States)

2016-04-01

Concrete bridge decks are susceptible to premature cracking and to corrosion of reinforcing steel. Low-permeability : concrete does not always ensure durability if the concrete has excessive cracks that facilitate the intrusion of aggressive solution...

Root maturation and dentin–pulp response to enamel matrix derivative in pulpotomized permanent teeth

Directory of Open Access Journals (Sweden)

Sherif S Darwish

2014-01-01

Full Text Available The success of pulpotomy of young permanent teeth depends on the proper selection of dressing materials. This study aimed to evaluate the histological and histomorphometric response of dentin–pulp complex to the enamel matrix derivative (Emdogain® gel compared to that of calcium hydroxide when used as a pulp dressing in immature young permanent dogs’ teeth. Dentin-like tissues bridging the full width of the coronal pulp at the interface between the injured and healthy pulp tissues were seen after 1 month in both groups. With time, the dentin bridge increased in thickness for calcium hydroxide but disintegrated and fully disappeared for Emdogain-treated group. Progressive inflammation and total pulp degeneration were only evident with Emdogain-treated group. The root apices of Emdogain-treated teeth became matured and closed by cementum that attached to new alveolar bone by a well-oriented periodontal ligament. In young permanent dentition, Emdogain could be a good candidate for periodontium but not dentino–pulpal complex regeneration.

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters.

Science.gov (United States)

Xiao, Feng; Chen, Gang S; Hulsey, J Leroy

2017-10-20

In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG) tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters

Directory of Open Access Journals (Sweden)

Feng Xiao

2017-10-01

Full Text Available In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Prestressed concrete. Composite material perfectly utilizing the merits of steel and concrete; Puresutoresu concrete. Ko to concreteto no tokucho wo kanzen ni ikashita fukugo sozai

Energy Technology Data Exchange (ETDEWEB)

Sugawara, M. [Kyokuto Kogen Concrete Shinko Co. Ltd., Tokyo (Japan)

1996-10-15

Since the early stage of the development of the prestressed concrete (PC) manufacturing techniques, it has been said that forming a single PC structure by uniting precast segments with PC steel material into one is a construction method making the most of the feature of PC. This paper roughly describes the history of the development of PC and concrete examples of PC, centering on the construction techniques effectively utilizing the principle of PC and its materials. Especially, a PC bridge is superior to a steel bridge with respect to noise and vibration, so that the construction works of replacing railway steel bridges and railway elevated bridges by PC bridges have come to be seen in many places recently. In order to increase the span of a PC bridge, the reduction of the weight is a major factor. Therefore, an outer cable system has come to be used so as to reduce the thickness is cross section of the web of a PC beam as much as possible. The changes of the maximum span of cable stayed bridge are listed in a table in comparison of PC bridges with steel bridges. 29 refs., 9 figs., 1 tab.

Non-destructive radiometry inspection technique for locating reinforcements and void/porosity in bridge bearings

International Nuclear Information System (INIS)

Yahaya bin Jafar; Jaafar bin Abdullah; Mohamad Azmi bin Ismail.

1989-01-01

Defects detection in bridge bearings is very important in controlling quality and safety. Typical manufacturing defects include misalligned or bent steel plates and the presence of voids/porosity within the rubber. A non-destructive radiometry inspection technique was used to locate steel plates position and the presence of voids/porosity in bridge bearing samples provided by the Rubber Research Institute of Malaysia (RRIM). Preliminary studies show that the mentioned defects can readily be determined by this technique. Some of the results are also presented. (author)

Synthesis of concrete bridge piles prestressed with CFRP systems.

Science.gov (United States)

2017-06-01

The Texas Department of Transportation frequently constructs prestressed concrete piles for use in bridge : foundations. Such prestressed concrete piles are typically built with steel strands that are highly susceptible to : environmental degradation...

Railway bridge monitoring during construction and sliding

Science.gov (United States)

Inaudi, Daniele; Casanova, Nicoletta; Kronenberg, Pascal; Vurpillot, Samuel

1997-05-01

The Moesa railway bridge is a composite steel concrete bridge on three spans of 30 m each. The 50 cm thick concrete deck is supported on the lower flanges of two continuous, 2.7 m high I-beams. The bridge has been constructed alongside an old metallic bridge. After demolishing this one, the new bridge has been slid for 5 m by 4 hydraulic jacks and positioned on the refurbished piles of the old bridge. About 30 fiber optic, low-coherence sensors were imbedded in the concrete deck to monitor its deformations during concrete setting and shrinkage, as well as during the bridge sliding phase. In the days following concrete pour it was possible to follow its thermal expansion due to the exothermic setting reaction and the following thermal and during shrinkage. The deformations induced by the additional load produced by the successive concreting phases were also observed. During the bridge push, which extended over six hours, the embedded and surface mounted sensors allowed the monitoring of the curvature variations in the horizontal plane due to the slightly uneven progression of the jacks. Excessive curvature and the resulting cracking of concrete could be ruled out by these measurements. It was also possible to observe the bridge elongation under the heating action of the sun.

[An artificial heart: bridge to transplantation or permanent?].

Science.gov (United States)

de Mol, Bas A J M; Lahpor, Jaap

2013-01-01

An artificial heart is a continuous-flow pump device with a constant output, which usually supports the left ventricle. Over the past five years, survival rates with an artificial heart have increased dramatically, but with an annual mortality of 10% per year compared with 6% for heart transplantation the artificial heart is mainly a 'bridge to transplantation' or an alternative for those patients who are not suitable for heart transplant, 'destination therapy'. It is anticipated that the number and severity of complications will decrease as a result of technological progress. The artificial heart could then become a long-term treatment option providing a good quality of life and thus become equivalent to a heart transplant.

Wind tunnel test of musi VI bridge

Science.gov (United States)

Permata, Robby; Andika, Matza Gusto; Syariefatunnisa, Risdhiawan, Eri; Hermawan, Budi; Noordiana, Indra

2017-11-01

Musi VI Bridge is planned to cross the Musi River in Palembang City, South Sumatera Province, Indonesia. The main span is a steel arch type with 200 m length and side span length is 75 m. Finite element analysis results showed that the bridge has frequency ratio for torsional and heaving mode (torsional frequency/heaving frequency)=1.14. This close to unity value rises concern about aerodynamic behaviour and stability of the bridge deck under wind loading. Sectional static and free vibration wind tunnel test were performed to clarify this phenomena in B2TA3 facility in Serpong, Indonesia. The test followed the draft of Guide of Wind Tunnel Test for Bridges developed by Indonesian Ministry of Public Works. Results from wind tunnel testing show that the bridge is safe from flutter instability and no coupled motion vibration observed. Therefore, low value of frequency ratio has no effect to aerodynamic behaviour of the bridge deck. Vortex-induced vibration in heaving mode occurred in relatively low wind velocity with permissible maximum amplitude value.

Guns, Germs and Steel

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 1. Guns, Germs and Steel - A Short History of Everybody for the Last 13,000 years. Suri Venkatachalam. Book Review Volume 6 Issue 1 January 2001 pp 84-88. Fulltext. Click here to view fulltext PDF. Permanent link:

Repair systems for deteriorated bridge piles : final report.

Science.gov (United States)

2017-04-01

The objective of this research project is to develop a durable repair system for deteriorated steel bridge piles that : can be implemented without the need for dewatering. A rigorous survey of the relevant practice nationwide was : conducted to infor...

Phase transformation system of austenitic stainless steels obtained by permanent compressive strain

Energy Technology Data Exchange (ETDEWEB)

Okayasu, Mitsuhiro, E-mail: mitsuhiro.okayasu@utoronto.ca; Tomida, Sai

2017-01-27

In order to understand more completely the formation of strain-induced martensite, phase structures were investigated both before and after plastic deformation, using austenitic stainless steels of various chemical compositions (carbon C=0.007–0.04 mass% and molybdenum Mo=0–2.10 mass%) and varying pre-strain levels (0–30%). Although the stainless steels consisted mainly of γ austenite, two martensite structures were generated following plastic deformation, comprising ε and α′ martensite. The martensitic structures were obtained in the twin deformation and slip bands. The severity of martensite formation (ε and α′) increased with increasing C content. It was found that α′ martensite was formed mainly in austenitic stainless steel lacking Mo, whereas a high Mo content led to a strong ε martensite structure, i.e. a weak α′ martensite. The formation of α′ martensite occurred from γ austenite via ε martensite, and was related to the slip deformation. Molybdenum in austenitic stainless steel had high slip resistance (or weak stress-induced martensite transformation), because of the stacking fault energy of the stainless steel affecting the austenite stability. This resulted in the creation of weak α′ martensite. Models of the martensitic transformations γ (fcc)→ε (hcp)→α′ (bcc) were proposed on both the microscopic and nanoscopic scales. The α′ martensite content of austenitic stainless steel led to high tensile strength; conversely, ε martensite had a weak effect on the mechanical strength. The influence of martensitic formation on the mechanical properties was evaluated quantitatively by statistical analysis.

Finite Element Analysis for Fatigue Damage Reduction in Metallic Riveted Bridges Using Pre-Stressed CFRP Plates

Directory of Open Access Journals (Sweden)

Elyas Ghafoori

2014-04-01

Full Text Available Many old riveted steel bridges remain operational and require retrofit to accommodate ever increasing demands. Complicating retrofit efforts, riveted steel bridges are often considered historical structures where structural modifications that affect the original construction are to be avoided. The presence of rivets along with preservation requirements often prevent the use of traditional retrofit methods, such as bonding of fiber reinforced composites, or the addition of supplementary steel elements. In this paper, an un-bonded post-tensioning retrofit method is numerically investigated using existing railway riveted bridge geometry in Switzerland. The finite element (FE model consists of a global dynamic model for the whole bridge and a more refined sub-model for a riveted joint. The FE model results include dynamic effects from axle loads and are compared with field measurements. Pre-stressed un-bonded carbon fiber reinforced plastic (CFRP plates will be considered for the strengthening elements. Fatigue critical regions of the bridge are identified, and the effects of the un-bonded post-tensioning method with different pre-stress levels on fatigue susceptibility are explored. With an applied 40% CFRP pre-stress, fatigue damage reductions of more than 87% and 85% are achieved at the longitudinal-to-cross beam connections and cross-beam bottom flanges, respectively.

ASPECTS REGARDING MECHANICAL PROCESSING OF STEELS FOR MAGNETS, NDFEB BASED

Directory of Open Access Journals (Sweden)

MELANIA TĂMAŞ

2015-05-01

Full Text Available This paper presents experimental research concerning the behavior on cutting by turning of steels for magnets NdFeB based. In this context, cutting by rough turning of steels magnet neodymium and boron ferrite based were performed. Turning processing with the values of the cutting parameters recommended by European Union and Sandvik Coromant company rules, taking into account the chemical composition of the processed material and cutting tool were performed. The tables have been drawn up with different values of the cutting parameters. By comparing these data it can be concluded that steels for permanent magnets, NdFeB based have acceptable behavior, the process by rough turning. A full assessment of the optimization of the cutting by turning process of steels for permanent magnet, NdFeB base will result from subsequent experimental research that will take into account the wear of cutting tools and quality (roughness of processed surface.

Development of High-Field Permanent Magnetic Circuits for NMRI/MRI and Imaging on Mice

Directory of Open Access Journals (Sweden)

Guangxin Wang

2016-01-01

Full Text Available The high-field permanent magnetic circuits of 1.2 T and 1.5 T with novel magnetic focusing and curved-surface correction are developed. The permanent magnetic circuit comprises a magnetic yoke, main magnetic steel, nonspherical curved-surface magnetic poles, plugging magnetic steel, and side magnetic steel. In this work, a novel shimming method is proposed for the effective correction of base magnetic field (B0 inhomogeneities, which is based on passive shimming on the telescope aspheric cutting, grinding, and fine processing technology of the nonspherical curved-surface magnetic poles and active shimming adding higher-order gradient coils. Meanwhile, the magnetic resonance imaging dedicated alloy with high-saturation magnetic field induction intensity and high electrical resistivity is developed, and nonspherical curved-surface magnetic poles which are made of the dedicated alloy have very good anti-eddy-current effect. In addition, the large temperature coefficient problem of permanent magnet can be effectively controlled by using a high quality temperature controller and deuterium external locking technique. Combining our patents such as gradient coil, RF coil, and integration computer software, two kinds of small animal Micro-MRI instruments are developed, by which the high quality MRI images of mice were obtained.

Steel fibre corrosion in cracks:durability of sprayed concrete

OpenAIRE

Nordström, Erik

2000-01-01

Steel fibre reinforced sprayed concrete is common practice for permanent linings in underground construction. Today there is a demand on "expected technical service life" of 120 years. Thin steel fibres could be expected to discontinue carrying load fast with a decrease of fibre diameter caused by corrosion, especially in cracks. The thesis contains results from inspections on existing sprayed concrete structures and a literature review on corrosion of steel fibres in cracked concrete. To stu...

Design and Finite Element Analysis of a Novel Transverse Flux Permanent Magnet Disk Generator

DEFF Research Database (Denmark)

Hosseini, Seyedmohsen; Moghani, Javad Shokrollahi; Ershad, Nima Farrokhzad

2011-01-01

This paper presents a novel structure of a transverse flux permanent magnet disk generator. The proposed disk shape structure simplifies prototyping by using simple laminated steel sheets in comparison with previous transverse flux structures that employ bent laminations and soft magnetic...... composites. Also the proposed structure has a higher power factor than what has been reported previously for transverse flux permanent magnet structures. After introducing the transverse flux permanent magnet disk generator, the design process is explained and a small power generator is designed...

Monitoring system of arch bridge for safety network management

Science.gov (United States)

Joo, Bong Chul; Yoo, Young Jun; Lee, Chin Hyung; Park, Ki Tae; Hwang, Yoon Koog

2010-03-01

Korea has constructed the safety management network monitoring test systems for the civil infrastructure since 2006 which includes airport structure, irrigation structure, railroad structure, road structure, and underground structure. Bridges among the road structure include the various superstructure types which are Steel box girder bridge, suspension bridge, PSC-box-girder bridge, and arch bridge. This paper shows the process of constructing the real-time monitoring system for the arch bridge and the measured result by the system. The arch type among various superstructure types has not only the structural efficiency but the visual beauty, because the arch type superstructure makes full use of the feature of curve. The main measuring points of arch bridges composited by curved members make a difference to compare with the system of girder bridges composited by straight members. This paper also shows the method to construct the monitoring system that considers the characteristic of the arch bridge. The system now includes strain gauges and thermometers, and it will include various sensor types such as CCTV, accelerometers and so on additionally. For the long term and accuracy monitoring, the latest optical sensors and equipments are applied to the system.

Effect of the dendritic morphology on hot tearing of carbon steels

International Nuclear Information System (INIS)

Ridolfi, M R

2016-01-01

Hot tears form during solidification in the brittle region of the dendritic front. Most hot tearing criteria are based on solid and fluid mechanics, being the phenomenon strictly depending on the solid resistance to applied strains and on the liquid capability of filling the void spaces. Modelling both mechanisms implies the precise description of the dendritic morphology. To this scope, the theory of coalescence of the dendritic arms at grain boundaries of Rappaz et al. has been applied, in this work, to the columnar growth of carbon steels by means of a simple mathematical model. Depending on the alloy composition, solid bridging starts at solid fractions down to about 0.8 and up to above 0.995 (very low carbon). The morphology of the brittle region changes drastically with increasing carbon and adding other solutes. In particular, ferritic dendrites, typical of low carbon steels, tend to offer short and wide interdendritic spaces to the surrounding liquid making possible their complete filling, and few solid bridges; peritectic steels show the rise of austenite growing and bridging rapidly in the interdendritic spaces, preventing void formation; austenitic dendrites form long and narrow interdendritic spaces difficult to reach for the liquid and with a lot of solid bridges. Sulphur addition mainly acts in delaying the coalescence end, more markedly in ferritic dendrites. (paper)

Problems of lamella flanges in steel bridge construction

Czech Academy of Sciences Publication Activity Database

Křístek, V.; Škaloud, Miroslav; Urushadze, Shota; Kunrt, J.

2016-01-01

Roč. 59, č. 1 (2016), s. 11-15 ISSN 2217-8139 R&D Projects: GA ČR(CZ) GA15-01035S Institutional support: RVO:68378297 Keywords : bridges * lamella flanges * repeated loading * breathing * limit states Subject RIV: JM - Building Engineering http://scindeks-clanci.ceon.rs/data/pdf/0543-0798/2016/0543-07981601011K.pdf

Experimental investigation on FRP to steel adhesively-bonded joint under tensile loading

NARCIS (Netherlands)

Jiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2012-01-01

Due to various advantages of Fibre-Reinforced Polymer (FRP) decks, the FRP to steel composite girder system is being increasingly used in the construction of new bridges as well as the rehabilitation projects of old bridges. This paper focus on the mechanical behaviors and failure modes of the

Statistical Analysis of Stress Signals from Bridge Monitoring by FBG System

Directory of Open Access Journals (Sweden)

Xiao-Wei Ye

2018-02-01

Full Text Available In this paper, a fiber Bragg grating (FBG-based stress monitoring system instrumented on an orthotropic steel deck arch bridge is demonstrated. The FBG sensors are installed at two types of critical fatigue-prone welded joints to measure the strain and temperature signals. A total of 64 FBG sensors are deployed around the rib-to-deck and rib-to-diagram areas at the mid-span and quarter-span of the investigated orthotropic steel bridge. The local stress behaviors caused by the highway loading and temperature effect during the construction and operation periods are presented with the aid of a wavelet multi-resolution analysis approach. In addition, the multi-modal characteristic of the rainflow counted stress spectrum is modeled by the method of finite mixture distribution together with a genetic algorithm (GA-based parameter estimation approach. The optimal probability distribution of the stress spectrum is determined by use of Bayesian information criterion (BIC. Furthermore, the hot spot stress of the welded joint is calculated by an extrapolation method recommended in the specification of International Institute of Welding (IIW. The stochastic characteristic of stress concentration factor (SCF of the concerned welded joint is addressed. The proposed FBG-based stress monitoring system and probabilistic stress evaluation methods can provide an effective tool for structural monitoring and condition assessment of orthotropic steel bridges.

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

Energy Technology Data Exchange (ETDEWEB)

Chintakunta, Satish R. [Engineering and Software Consultants, Inc., 14123 Robert Paris Ct., Chantilly, VA 20151 (United States); Boone, Shane D. [Federal Highway Administration, Turner Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101 (United States)

2014-02-18

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

Science.gov (United States)

Chintakunta, Satish R.; Boone, Shane D.

2014-02-01

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

RECONSTRUCTION AND REINFORCEMENT OF BRIDGE ACROSS THE RIVER. SYLVA IN KUNGUR, RUSSIA

Directory of Open Access Journals (Sweden)

R. Ye. Heizn

2010-04-01

Full Text Available Sylva Bridge at Kungur city is one of the oldest road bridges in Perm region, the West Urals, Russia. Its erection was begun in 1912 and was interrupted with the First World War and the further events in Russia. The bridge was opened only in 1931. For 75 years of bridge operation the most part of bridge constructions has been acquired plural damages, both mechanical and corrosion. After the bridge inspection in 2003 and according to the calculations of its capacity, the decision on reconstruction of the bridge was accepted. The purpose of rehabilitation was to replace the timber deck by steel orthotropic deck with asphalt pavement. A new deck was to be engaged in combined action with the existing metal structures with the help of socles with high-strength bolts. Due to this, the bridge carrying capacity was increased as required by the present standards. In 2006, after tests, the bridge was opened for traffic.

Design and construction of a cable-stayed composite girder bridge with precast RC-slabs; Purekyasuto shohan gosei keta shachokoyo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Maeda, K. [Tokyo Metropolitan Univ. (Japan). Faculty of Technology; Shimura, T.; Tachibana, Y.; Echigo, S. [Kawada Industries Inc., Tokyo (Japan)

1995-09-20

A report on design and execution of cable-stayed composite girder bridge with precast RC-slabs constructed first in Japan though in small scale was described. This bridge adopted steel slabs relatively low in slab height for main slab and with two boxes slab section, and was designed at an aim of being more economic and shorter in its working term in comparison with steel girder slab type, on a base of the design in a region allowable with the existing design standards. This bridge is mainly in accordance with the regulation on continuous bridge in the prescription of road bridge, and is designed for normal RC-girder selecting between girder supports to direction normal to bridge axis as usual without using specially strong concrete to the girder. And, in order to fill with the regulation on allowable tensile stress on considering effects of creep and drying shrinkage, a method adding prestress to the slabs was adopted. Furthermore, a loop-like overlap joint for cable joint for the precast girders, expansion concrete for joint portion to compose the girder with the steel slab and so forth were adopted. 12 refs., 22 figs., 5 tabs.

A study on the impediment of thickness diminution of Carbon steel tube by using a applied magnetic field

International Nuclear Information System (INIS)

Kim, Jong Oh; Kim, Jong Hui; Cho, Wan Sik; Hong, Sung Min; Park, Yun Won

2001-03-01

Magnetic properties of the carbon steel tube which is used as the pipe laying of cooling water in nuclear power plant were measured to research the impediment of thickness diminution of carbon steel tube. Magnetic field distribution of carbon steel tube in the applied magnetic field was simulated by computer program. On the basis of the simulation results, Alnico 5DG and Alnico 5 were selected as the permanent magnets applicable to the carbon steel tube. Sm2Co17 magnet was used to compare the performance of permanent magnets. The experimental apparatus similar to the draining environment of cooling water in nuclear power plant was also manufactured in order to research the impediment of thickness diminution of carbon steel carbon tube

Prestressed concrete cable-stayed bridge; PC shachokyo `Tajiri sky bridge` no seko

Energy Technology Data Exchange (ETDEWEB)

Kaida, Y.; Tsujino, F. [Osaka Prefectural Government Office, Osaka (Japan); Yamamoto, T.; Hishiki, Y.; Saito, K.

1995-01-30

The outline on the execution of PC cable-stayed bridge `Tajiri Sky Bridge` which was built at the opposite coast of Kansai International Airport was reported. This bridge is a double-sided suspension PC cable-stayed bridge with a tower height of 93.6 m having a main beam which is 26.3 m wide, featuring H-type main tower with one side beam, a smooth main beam structure, the leg top part with a large section, etc. A large-capacity factory manufacturing type non-grout cable with a pull strength of 1,900 ton class was adopted for the diagonal bracing. The leg top part is in a massive concrete structure so that, for avoiding the crack of cement due to temperature, a low heat build-up furnace cement was adopted, the water reducing agent was used, pre-cooling and side-clamping PC steel material were adopted and moderate pre-stress was introduced. In the execution of the connection part of the main beam, for preventing the deflection fluctuation due to the change of the main beam/main tower/diagonal bracing due to temperature and vibration due to wind, the earth anchor was used to tentatively fix the extended part. During execution, the wind velocity was strong reaching 25 m/s, which did not produce any problems. 1 ref., 24 figs., 3 tabs.

New And Existing Bridge Constructions - Increase of Fatigue Strength of Welded Joints by High Frequency Mechanical Impact Treatment

Directory of Open Access Journals (Sweden)

Ummenhofer Thomas

2013-07-01

Full Text Available Numerous studies at KIT prove that high frequency mechanical impact (HFMI treatment is an efficient method for increasing the fatigue strength of welded steel structures. Within different research projects it was found that HFMI-methods can be used successfully for new and existing structures in order to extend the fatigue life. This paper gives an overview of the current status of existing steel bridges in Germany regarding aspects like bridge age distributions and traffic loads. Based on that overview welded joints susceptible to fatigue failure are identified. Using component-like small scale specimens, HFMI-methods were investigated within the objective of implementing an effective application for new and existing structures. Applying the fatigue test data observed, existing design proposals are evaluated and design recommendations for HFMI-treated joints are given. As a result of the research work, a transfer into practice has been realized and different applications are illustrated using the example of bridge constructions made of steel.

Structural Performance Evaluation of Tsing MA Bridge Deck Using Long-Term Monitoring Data

Science.gov (United States)

Ni, Y. Q.; Xia, H. W.; Ko, J. M.

The Tsing Ma Bridge in Hong Kong is suspension bridge with a main span of 1377 m carrying both highway and railway traffic. After completing its construction in 1997, the bridge was instrumented by the Hong Kong SAR Government Highways Department with a long-term structural health monitoring system comprising about 300 sensors permanently installed on the bridge. As part of this monitoring system, a total of 110 strain gauges have been installed to measure strain at the deck cross-sections and bearings. In this study, a method for real-time structural performance evaluation of the stiffening deck system making use of long-term strain measurement data is proposed and verified using the strain monitoring data from a typical deck cross-section of the Tsing Ma Bridge.

Reserves in load capacity assessment of existing bridges

Science.gov (United States)

Žitný, Jan; Ryjáček, Pavel

2017-09-01

High percentage of all railway bridges in the Czech Republic is made of structural steel. Majority of these bridges is designed according to historical codes and according to the deterioration, they have to be assessed if they satisfy the needs of modern railway traffic. The load capacity assessment of existing bridges according to Eurocodes is however often too conservative and especially, braking and acceleration forces cause huge problems to structural elements of the bridge superstructure. The aim of this paper is to review the different approaches for the determination of braking and acceleration forces. Both, current and historical theoretical models and in-situ measurements are considered. The research of several local European state norms superior to Eurocode for assessment of existing railway bridges shows the big diversity of used local approaches and the conservativeness of Eurocode. This paper should also work as an overview for designers dealing with load capacity assessment, revealing the reserves for existing bridges. Based on these different approaches, theoretical models and data obtained from the measurements, the method for determination of braking and acceleration forces on the basis of real traffic data should be proposed.

Geodetic monitoring (TLS of a steel transport trestle bridge located in an active mining exploitation site

Directory of Open Access Journals (Sweden)

Skoczylas Arkadiusz

2016-09-01

Full Text Available Underground mining exploitation causes, in general, irregular vertical and horizontal shifts in the superficial layer of the rock mass. In the case of construction objects seated on this layer, a deformation of the object’s foundation can be observed. This leads to additional loads and deformations. Identification of surface geometry changes in construction objects located within the premises of underground mining exploitation areas is an important task as far as safety of mining sites is concerned. Surveys targeting shifts and deformations in engineering objects preformed with the use of classic methods are of a selective nature and do not provide the full image of the phenomenon being the subject of the observation. This paper presents possibilities of terrestrial laser scanning technology application in the monitoring of engineering objects that allows for a complete spatial documentation of an object subjected to the influence of an active mining exploitation. This paper describes an observation of a 100 m section of a steel transport trestle bridge located on the premises of hard coal mine Lubelski Węgiel “Bogdanka” S.A. carried out in 2015. Measurements were carried out using a Z+F Imager 5010C scanner at an interval of 3.5 months. Changes in the structure’s geometry were determined by comparing the point clouds recorded during the two measurement periods. The results of the analyses showed shifts in the trestle bridge towards the exploited coal wall accompanied by object deformation. The obtained results indicate the possibility of of terrestrial laser scanning application in studying the aftereffects of underground mining exploitation on surface engineering objects.

Yonjung High-Speed Railway Bridge Assessment Using Output-Only Structural Health Monitoring Measurements under Train Speed Changing

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Mosbeh R. Kaloop

2016-01-01

Full Text Available Yonjung Bridge is a hybrid multispan bridge that is designed to transport high-speed trains (HEMU-430X with maximum operating speed of 430 km/h. The bridge consists of simply supported prestressed concrete (PSC and composite steel girders to carry double railway tracks. The structural health monitoring system (SHM is designed and installed to investigate and assess the performance of the bridge in terms of acceleration and deformation measurements under different speeds of the passing train. The SHM measurements are investigated in both time and frequency domains; in addition, several identification models are examined to assess the performance of the bridge. The drawn conclusions show that the maximum deflection and acceleration of the bridge are within the design limits that are specified by the Korean and European codes. The parameters evaluation of the model identification depicts the quasistatic and dynamic deformations of PSC and steel girders to be different and less correlated when higher speeds of the passing trains are considered. Finally, the variation of the frequency content of the dynamic deformations of the girders is negligible when high speeds are considered.

Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

International Nuclear Information System (INIS)

Ho, Duc Duy; Hong, Dong Soo; Kim, Jeong Tae

2010-01-01

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

OpenAIRE

Chen, Zheheng; Guo, Tong; Yan, Shengyou

2015-01-01

Structural health monitoring (SHM) has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC) bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway...

Bridge Collapse Revealed By Multi-Temporal SAR Interferometry

Science.gov (United States)

Sousa, Joaquim; Bastos, Luisa

2013-12-01

On the night of March 4, 2001, the Hintze Ribeiro centennial Bridge, made of steel and concrete, collapsed in Entre-os-Rios (Northern Portugal), killing 59 people, including those in a bus and three cars that were attempting to reach the other side of the Douro River. It still remains the most serious road accident in the Portuguese history. In this work we do not intend to corroborate or contradict the official version of the accident causes, but only demonstrate the potential of Multi-Temporal Interferometric (MTI-InSAR) techniques for detection and monitoring of deformations in structures such as bridges, helping to prevent new catastrophic events. Based on the analysis of 57 ERS-1/2 covering the period from December 1992 to the fatality occurrence, we were able to detect significant movements (up to 20 mm/yr) in the section of the bridge that fell in the Douro River, obvious signs of the bridge instability.

MR damping system on Dongting Lake cable-stayed bridge

Science.gov (United States)

Chen, Z. Q.; Wang, X. Y.; Ko, J. M.; Ni, Y. Q.; Spencer, Billie F., Jr.; Yang, G.

2003-08-01

The Dongting Lake Bridge is a cable-stayed bridge crossing the Dongting Lake where it meets the Yangtze River in southern central China. After this bridge was completed in 1999, its cables were observed to be sensitive to rain-wind-induced vibration, especially under adverse weather conditions of both rain and wind. To investigate the possibility of using MR damping systems to reduce cable vibration, a joint project between the Central South University of China and the Hong Kong Polytechnic University was conducted. Based on the promising research results, the bridge authority decided to install MR damping systems on the longest 156 stay cables. The installation started in July 2001 and finished in June 2002, making it the world's first application of MR dampers on cable-stayed bridge to suppress the rain-wind-induced cable vibration. As a visible and permanent aspect of bridge, the MR damping system must be aesthetically pleasing, reliable, durable, easy to maintain, as well as effective in vibration mitigation. Substantial work was done to meet these requirements. This paper describes the implementation of MR damping systems for cable vibration reduction.

The anchors of steel wire ropes, testing methods and their results

Directory of Open Access Journals (Sweden)

J. Krešák

2012-10-01

Full Text Available The present paper introduces an application of the acoustic and thermographic method in the defectoscopic testing of immobile steel wire ropes at the most critical point, the anchor. First measurements and their results by these new defectoscopic methods are shown. In defectoscopic tests at the anchor, the widely used magnetic method gives unreliable results, and therefore presents a problem for steel wire defectoscopy. Application of the two new methods in the steel wire defectoscopy at the anchor point will enable increased safety measures at the anchor of steel wire ropes in bridge, roof, tower and aerial cable lift constructions.

Design and construction of the Natorigawa Bridge; Natorigawa kyoryo no sekkei/seko

Energy Technology Data Exchange (ETDEWEB)

Murai, Y.; Oba, M.; Omurata, Y. [JR East Japan Railway Co., Tokyo (Japan); Miyauchi, M.; Iwasaki, I. [Taisei Corp., Tokyo (Japan)

1997-03-31

The Natorigawa Bridge is reconstructed. Out of the reconstruction work, a report is made mainly on the design of the superstructure work of the PC panel-stayed bridge and the details of the work. In selecting bridge type, PC simple through beam bridge, steel trussed bridge, PC cable-stayed bridge, and PC panel-stayed bridge are compared, and a 2-span continuous PC panel-stayed bridge is adopted. Its appearance resembles that of the cable-stayed bridge, but the structure resembles a girder bridge. The appropriate span length is the intermediate range between those of the girder bridge and the cable-stayed bridge. Its trafficability is excellent with little deformation by the running of trains because the main beam, diagonal panel, and the main tower are connected rigidly to provide high rigidity of the entire bridge. PRC structure is employed in consideration of the restriction to beam height and economical efficiency. Analyses by a FEM model using two dimensional plane elements and by a few plane frame models as well as comparison of sectional force are performed for this bridge, and a proper plane model is selected. Substructure work, superstructure work and measurement work are described. 3 refs., 16 figs., 6 tabs.

Testing methods of steel wi re ropes at the anchor

Directory of Open Access Journals (Sweden)

Stanislav Kropuch

2012-12-01

Full Text Available The present paper introduces an application of the acoustic andthermographic method in the defectoscopic testing of immobilesteel wire ropes at the most critical point, the anchor. Firstmeasurements and their results by these new defectoscopic methodsare shown. In defectoscopic tests at the anchor, the widelyused magnetic method gives unreliable results, and therefore presentsa problem for steel wire defectoscopy. Application of the two new methods in the steel wire defectoscopy at the anchor point will enableincreased safety measures at the anchor of steel wire ropes in bridge, roof, tower and aerial cable lift constructions.

Standard guide for mutual inductance bridge applications for wall thickness determinations in boiler tubing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This guide describes a procedure for obtaining relative wall thickness indications in ferromagnetic and non-ferromagnetic steels using the mutual inductance bridge method. The procedure is intended for use with instruments capable of inducing two substantially identical magnetic fields and noting the change in inductance resulting from differing amounts of steel. It is used to distinguish acceptable wall thickness conditions from those which could place tubular vessels or piping at risk of bursting under high temperature and pressure conditions. 1.2 This guide is intended to satisfy two general needs for users of industrial Mutual Inductance Bridge (MIB) equipment: (1) the need for a tutorial guide addressing the general principles of Mutual Inductance Bridges as they apply to industrial piping; and (2) the need for a consistent set of MIB performance parameter definitions, including how these performance parameters relate to MIB system specifications. Potential users and buyers, as well as experienced M...

Study on the selection of steel or prestressed concrete cable stayed bridge by using diaggregate behavioral model; Hishukei rojitto model wo mochiita koshachokyo to PC shachokyo no kyoshiki sentaku ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Araki, Y.; Furuta, H.; Maeda, E.; Furukawa, K. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering

1994-09-15

A discussion was given to make clear the selection factors in selecting bridge types (steel cable stayed bridge and prestressed concrete cable stayed bridge). The discussion is intended to consider the future development of both bridges. Quoting a cable stayed bridge with a span length of 250 m that can be selected from either bridge, an evaluation was made by using calculations that uses the disaggregate behavioral model theory based on questionnaire responses from engineers. The analysis uses the following procedure: utility function values of the two term behavioral model (having two choices) are specified and the characteristics variables are selected; the data are prepared according to the specifications, which are used to estimate parameters by a maximum likelihood estimation method; and estimation amount is estimated by using the covariance matrix, which is given a `t` value verification. The conclusions: what gives the large effect to the selection is the engineering capacity and sociality; the result contains vocational consciousness; the economy is measured by the large weight of construction cost for the upper part structures and cost required for large repairs; materials affect largely the reliability, and so does the technological level the constructibility; the comprehensive technical capability, freedom in design and the experience attained by Japan have great effects in terms of technological capability. 10 refs., 10 figs., 11 tabs.

Fatigue Assessment of Full-Scale Retrofitted Orthotropic Bridge Decks

NARCIS (Netherlands)

Teixeira De Freitas, S.; Kolstein, M.H.; Bijlaard, F.S.K.

2017-01-01

Full-scale fatigue tests were performed on two retrofitted orthotropic bridge decks (OBDs). The retrofitting systems consist of adding a second steel plate on the top of the existing deck. The aim is to reduce the stresses at the fatigue-sensitive details and therefore extend the fatigue life of

An influence of technological contraflexure of crane bridges on its durability

Directory of Open Access Journals (Sweden)

Artur BLUM

2010-01-01

Full Text Available Standard requirements till 1996 year during bridge crane manufacturing demanded a positive technological contraflexure. As a result of this process were implemented technological compressive stress into tensile zone from inertial and operational loads and tensile stress into compressive zone. This way there were redistributed resultant stress which have increased fatigue strength of exploited crane bridges. Actually valid standard PN-ISO 7363 has removed this obligatory requirement. Its use depends of crane buyer demands. Reduction of initial positive deflection can be seen after few years of crane operations. It is a case of girders permanent deflections increment. Article presents method of technological prestressing of bridge girders with its practical application to obtain positive contrafexure.

A study on ship impacting a flexible crashworthy device for protecting bridge pier

Directory of Open Access Journals (Sweden)

Yang Liming

2015-01-01

Full Text Available As the accident of a vessel impacting a bridge pier will cause serious disaster, such as destroyed bridge, sinking ship and polluting environment, the technology and method to protect bridge pier from ship collision have been widely investigated recently. Due to the huge kinetic energy of large-tonnage ship and the short time duration in the collision, the studies involve impact mechanics. A developed flexible crashworthy device has been developed to protect bridges, which consists of an outer steel-periphery, an inner steel-periphery and the rubber coating SWRCs(soft elements installed between them. When the SWRC crashworthy device is installed, the collision duration under low impact force is prolonged due to its high compliance, which results in the ship having enough time to turn its navigation direction and most of the remainder kinetic energy being carried off by the turned away ship. Consequently, both impact forces on the ship and on the bridge pier decrease markedly. This is the key reason as to why the SWRC crashworthy device can avoid the destruction of both the bridge and the ship. Based on our results of theoretical studies and numerical simulations, the present paper will propose an experiment-adopted a real ship to impact a flexible crashworthy device. The collision test has been performed 12 times with different speed, carrying capacity, and impact angle of the ship. After the experiments, the ship, flexible crashworthy device and the pier are not damaged. The experiments show that the flexible crashworthy device can turn away the impact ship, so that the ship moves along the outer part of the device, which reduces the ship impact force on the bridge pier obviously. It not only protects bridges but also avoids the damage to ships.

Stiffness of Railway Soil-Steel Structures

Directory of Open Access Journals (Sweden)

Machelski Czesław

2015-12-01

Full Text Available The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces, as in bridges. The analyzed cases show that the shell’s span, geometry (static scheme and the height of earth fill influence the stiffness of the structure. The soil-steel structure’s characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

Stiffness of Railway Soil-Steel Structures

Science.gov (United States)

Machelski, Czesław

2015-12-01

The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness) become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces), as in bridges. The analyzed cases show that the shell's span, geometry (static scheme) and the height of earth fill influence the stiffness of the structure. The soil-steel structure's characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

Expected damages of retrofitted bridges with RC jacketing

Science.gov (United States)

Montes, O.; Jara, J. M.; Jara, M.; Olmos, B. A.

2015-07-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models.

Expected damages of retrofitted bridges with RC jacketing

International Nuclear Information System (INIS)

Montes, O; Jara, J M; Jara, M; Olmos, B A

2015-01-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models. (paper)

In-situ magnetization of NdFeB magnets for permanent magnet machines

International Nuclear Information System (INIS)

Chang, L.; Eastham, T.R.; Dawson, G.E.

1991-01-01

In-situ magnetizers are needed to facilitate the assembly of permanent magnet machines and to remagnetize the magnets after weakening due to a fault condition. The air-core magnetizer in association with the silicon steel lamination structure of the rotor has advantages over its iron-core counterpart. This novel method has been used to magnetize the NdFeB magnets in a 30-hp permanent magnet synchronous motor. The magnetizing capability for different magnetizer geometries was investigated for the magnetization of NdFeB material. The design, testing, and operation of this magnetizer are reported in this paper

The magnetic properties of mill scale-derived permanent magnet

International Nuclear Information System (INIS)

Woon, H.S.; Hashim, M.M.; Yahya, N.; Zakaria, A.; Lim, K.P.

2005-01-01

In the permanent magnet SrO-FeO-Fe 2 O 3 system, there exist several magnetically ordered compounds with a stable phase at room temperature. The most important are the M(SrFe 12 O 19 ), X(SrFe 15 O 23 ) and W(SrFe 18 O 27 ) phases with hexagonal close packed structure. In this project, M(SrFe 12 O 19 ) was prepared using mill scale, a steel-maker byproduct, as raw material. The Malaysia steel industry generates approximately 30,000 metric tons of waste products such as mill scale every year. Transportation and disposal of the byproducts are costly and the environmental regulations are becoming stricter. Hence, local steel mills are to find new ways to recycle the waste as a feedstock for the steel-making process or as a saleable product. The M(SrFe 12 O 19 ) was synthesized using the conventional ceramic process. The formation of the SrFe 12 O 19 was confirmed by X-ray diffraction. The magnetic properties such as the energy product (BH)max, coercive force (iHc) and remanence (Br) were also reported in this paper. (Author)

Nonlinear seismic analysis of continuous RC bridge

Directory of Open Access Journals (Sweden)

Čokić Miloš M.

2017-01-01

Full Text Available Nonlinear static analysis, known as a pushover method (NSPA is oftenly used to study the behaviour of a bridge structure under the seismic action. It is shown that the Equivalent Linearization Method - ELM, recommended in FEMA 440, is appropriate for the response analysis of the bridge columns, with different geometric characteristics, quantity and distribution of steel reinforcement. The subject of analysis is a bridge structure with a carriageway plate - a continuous beam with three spans, with the 24 + 40 + 24 m range. Main girder is made of prestressed concrete and it has a box cross section of a constant height. It is important to study the behaviour, not only in the transverse, but also in the longitudinal direction of the bridge axis, when analysing the bridge columns exposed to horizontal seismic actions. The columns were designed according to EN1992, parts 1 and 2. Seismic action analysis is conducted according to EN 1998: 2004 standard. Response spectrum type 1, for the ground type B, was applied and the analysis also includes 20% of traffic load. The analysis includes the values of columns displacement and ductility. To describe the behaviour of elements under the earthquake action in both - longitudinal and transverse direction, pushover curves were formed.

Study on Performance of Steel Fiber Concrete Bridge Pier Specimens under Horizontal Cyclic Loading

Directory of Open Access Journals (Sweden)

Baiben Chen

2017-01-01

Full Text Available Because of that steel fiber can effectively prevent the extension and development of small cracks in the concrete, steel fiber reinforced concrete has good toughness and tensile strength. In the application of building materials, steel fiber reinforced concrete is an ideal elastic-plastic material. For the seismic performance, it has advantages. In order to analyze the seismic performance of steel fiber reinforced concrete, 4 piers of the scale model test under horizontal cyclic loading were done. The results showed that failure mode of steel fiber reinforced concrete is better than that of ordinary concrete, and has a large yield moment under the external loads.

Vibration monitoring of long bridges and their expansion joints and seismic devices

OpenAIRE

Islami Kleidi

2015-01-01

This paper presents a number of recently installed Structural Health Monitoring (SHM) systems: a) on a 2km double suspension bridge; b) on a long railway viaduct that has experienced cracking; and c) on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, desig...

Detection and characterization of corrosion of bridge cables by time domain reflectometry

Science.gov (United States)

Liu, Wei; Hunsperger, Robert G.; Folliard, Kevin; Chajes, Michael J.; Barot, Jignesh; Jhaveri, Darshan; Kunz, Eric

1999-02-01

In this paper, we develop and demonstrate a nondestructive evaluation technique for corrosion detection of embedded or encased steel cables. This technique utilizes time domain reflectometry (TDR), which has been traditionally used to detect electrical discontinuities in transmission lines. By applying a sensor wire along with the bridge cable, we can model the cable as an asymmetric, twin-conductor transmission line. Physical defects of the bridge cable will change the electromagnetic properties of the line and can be detected by TDR. Furthermore, different types of defects can be modeled analytically, and identified using TDR. TDR measurement results from several fabricated bridge cable sections with built-in defects are reported.

Design of portable bridge of material access on level 8 m

International Nuclear Information System (INIS)

Hasibuan, D.

1999-01-01

Base on the planning to increase of the working capability of the rabbit system facility, using the design of mentioned portable bridge on material access has been done. Using the designed installation, the transportation of the middle and high active samples from the isotop cell to the scanning room will be easy to be done. The design has been done by using the maximum actual load, and also the chosen steel shape dimension compliance with ASTM standard. The installation required 2 pieces of W 6 x 12 steel beam by 111.82 inches in length, 4 pieces W 6 x 12 steel beam by 47.25'' in length and a piece of steel plate by 111.82'' x 47.25'' x 0.394''. This paper concluded that this design is feasible to be fabricated

Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

Directory of Open Access Journals (Sweden)

Xu Jiang

2016-01-01

Full Text Available The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-bonded joint during tests, a specific loading device is developed with the capacity of providing six different loading angles, which are 0°(pure tension, 18°, 36°, 54°, 72° and 90°(pure shear. Failure modes of adhesively-bonded joints are investigated. It indicates that, for the pure shear loading, the failure mode is the cohesive failure (near the interface between the adhesive layer and the steel support in the adhesive layer. For the pure tensile and combined loading conditions, the failure mode is the combination of fiber breaking, FRP delamination and interfacial adhesion failure between the FRP sandwich deck and the adhesive layer. The load-bearing capacities of adhesive joints under combined loading are much lower than those of the pure tensile and pure shear loading conditions. According to the test results of six angle loading conditions, a tensile/shear failure criterion of the adhesively-bonded joint is obtained. By using Finite Element (FE modeling method, linear elastic simulations are performed to characterize the stress distribution throughout the adhesively-bonded joint.

Bridge monitoring by interferometric deformation sensors

Science.gov (United States)

Inaudi, Daniele; Vurpillot, Samuel; Casanova, Nicoletta

1996-09-01

In many concrete bridges, the deformations are the most relevant parameter to be monitored in both short and long- terms. Strain monitoring gives only local information about the material behavior and too many such sensors would therefore be necessary to gain a complete understanding of the bridge behavior. We have found that fiber optic deformation sensors, with measurement bases of the order of one to a few meters, can give useful information both during the first days after concrete pouring and in the long term. In a first phase it is possible to monitor the thermal expansion due to the exothermic setting reaction and successively the thermal and drying shrinkages. Thanks to the long sensor basis, the detection of a crack traverse to the measurement region becomes probable and the evolution of cracks can therefore be followed with a reduced number of sensors. In the long-term it is possible to measure the geometric deformations and therefore the creeping of the bridge under static loads, especially under its own weight. In the past two years, our laboratory has installed hundreds of fiber optic deformation sensors in more than five concrete, composite steel-concrete, refurbished and enlarged bridges (road, highway and railway bridges). The measuring technique relies on low-coherence interferometry and offers a resolution down to a few microns even for long-term measurements. This contribution briefly discusses the measurement technique and then focuses on the development of a reliable sensor for direct concrete embedding and on the experimental results obtained on these bridges.

Design of pedestrian truss bridge with Sengon-Rubber laminated veneer lumber

Science.gov (United States)

Herbudiman, B.; Pranata, Y. A.; Pangestu, L.

2017-12-01

Timber bridges are one of the bridge that has long been used, but nowadays, large dimension of sawn timber has limited supply and also it is not environmental-friendly. Laminated veneer lumber (LVL) is a engineered wood that becomes one of the promising alternative, because it is made from lower quality wood that processed to be used as a more quality one. The bridge planned to be a pedestrian truss bridge with length of 9 m, width of 3 m, height of 2.5 m, and using bolt and steel plate as its connection system. Mechanical properties of LVL obtained directly from laboratory test result. Bridge modeling and planning for wood construction refers to SNI 7973:2013, while the loading refers to SNI 1725:2016. Based on the modelling and calculation, the dimension of truss frame and girder beam which are 9 cm x 9 cm and 9 cm x 18 cm have adequate strengths and satisfy deflection requirement.

Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

Directory of Open Access Journals (Sweden)

Yue Zheng

2015-01-01

Full Text Available This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abutment and the girder. The detailed nonlinear finite element (FE model is established and the steel girder and the reinforced concrete piers are modeled by nonlinear fiber elements. The pounding element of the abutment is simulated by using a trilinear compression gap element. The elastic-perfectly plastic element is used to model the nonlinear rubber bearings. The comparisons of the pounding forces, the shear forces of the nonlinear bearings, the moments of reinforced concrete piers, and the axial pounding stresses of the steel girder are studied. The made observations indicate that the nonuniform excitation for multisupport bridge is imperative in the analysis and evaluation of the pounding effects of the bridges.

Modern high strength QT, TM and duplex-stainless steels

Energy Technology Data Exchange (ETDEWEB)

Bocquet, P. [Industeel (France); Luxenburger, G. [Aktiengesellschaft der Dillinger Huettenwerke, Dillingen/Saar (Germany); Porter, D. [Rautaruukki (Finland); Ericsson, C. [Avesta Polarit (Sweden)

2003-07-01

Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

Modern high strength QT, TM and duplex-stainless steels

International Nuclear Information System (INIS)

Bocquet, P.; Luxenburger, G.; Porter, D.; Ericsson, C.

2003-01-01

Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

Energy Technology Data Exchange (ETDEWEB)

Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

1998-06-15

The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

Continuous fatigue crack monitoring of bridges: Long-Term Electrochemical Fatigue Sensor (LTEFS)

Science.gov (United States)

Moshier, Monty A.; Nelson, Levi; Brinkerhoff, Ryan; Miceli, Marybeth

2016-04-01

Fatigue cracks in steel bridges degrade the load-carrying capacity of these structures. Fatigue damage accumulation caused by the repetitive loading of everyday truck traffic can cause small fatigue cracks initiate. Understanding the growth of these fatigue cracks is critical to the safety and reliability of our transportation infrastructure. However, modeling fatigue in bridges is difficult due to the nature of the loading and variations in connection integrity. When fatigue cracks reach critical lengths failures occur causing partial or full closures, emergency repairs, and even full structural failure. Given the aging US highway and the trend towards asset management and life extension, the need for reliable, cost effective sensors and monitoring technologies to alert bridge owners when fatigue cracks are growing is higher than ever. In this study, an innovative Long-Term Electrochemical Fatigue Sensor (LTEFS) has been developed and introduced to meet the growing NDT marketplace demand for sensors that have the ability to continuously monitor fatigue cracks. The performance of the LTEFS has been studied in the laboratory and in the field. Data was collected using machined specimens with different lengths of naturally initiated fatigue cracks, applied stress levels, applied stress ratios, and for both sinusoidal and real-life bridge spectrum type loading. The laboratory data was evaluated and used to develop an empirically based algorithm used for crack detection. Additionally, beta-tests on a real bridge structure has been completed. These studies have conclusively demonstrated that LTEFS holds great potential for long-term monitoring of fatigue cracks in steel structures

Assessment of the environmental effects associated with wooden bridges preserved with creosote, pentachlorophenol, or chromated copper arsenate

Science.gov (United States)

Kenneth M. Brooks

Timber bridges provide an economical alternative to concrete and steel structures, particularly in rural areas with light to moderate vehicle traffic. Wooden components of these bridges are treated with chromated copper arsenate type C (CCA), pentachlorophenol, or creosote to prolong the life of the structure from a few years to many decades. This results in reduced...

Advanced analysis and design for fire safety of steel structures

CERN Document Server

Li, Guoqiang

2013-01-01

Advanced Analysis and Design for Fire Safety of Steel Structures systematically presents the latest findings on behaviours of steel structural components in a fire, such as the catenary actions of restrained steel beams, the design methods for restrained steel columns, and the membrane actions of concrete floor slabs with steel decks. Using a systematic description of structural fire safety engineering principles, the authors illustrate the important difference between behaviours of an isolated structural element and the restrained component in a complete structure under fire conditions. The book will be an essential resource for structural engineers who wish to improve their understanding of steel buildings exposed to fires. It is also an ideal textbook for introductory courses in fire safety for master’s degree programs in structural engineering, and is excellent reading material for final-year undergraduate students in civil engineering and fire safety engineering. Furthermore, it successfully bridges th...

Progress of optical sensor system for health monitoring of bridges at Chongqing University

Science.gov (United States)

Chen, W.; Fu, Y.; Zhu, Y.; Huang, S.

2005-02-01

With decades of research experience on optical sensors, Optoelectronic Technology Lab of Chongqing University (OTLCU) has studied on a variety of sensors system designed for practical use in health monitoring. In OTLCU, embedded and surface mounted fiber Fabry-Perot strain sensor has been developed for monitoring the local strain of both concrete and steel truss bridge. Optoelectronic deflect meter, with a group of optical level sensor in a series connected pipe, was developed for deflection monitoring and line shape monitoring of the bridges. Laser deflect meter, with a laser pointer and a sensors array, has been also developed for a dynamic deflection monitoring of the bridges. To monitoring the 2-Dimentional displacement of the bridge, a self-calibrating imaging system was developed. All these sensor systems have been applied in different bridges successfully. This paper briefly describes principle of these optical sensing systems, and also gives some representative results of the system in practical application of bridges.

Post-irradiation creep properties of four plates and two forgings DIN 1.4948 steel from the SNR-300 permanent primary structures

International Nuclear Information System (INIS)

Schaaf, B. van der.

1987-01-01

The safety authorities, involved in the licensing procedure of the SNR-300, have required the determination of the irradiation effect on the heat-to-heat variation of tensile and creep properties of Werkst. No. DIN 1.4948 austenitic stainless steel. These data are lacking in the present codes and they are necessary for the design and safety considerations of the permanent structures. Results are presented of about 200 tests on irradiated and unirradiated material of 6 heats used in the production of the SNR-300 permanent structures. After irradiation in the HFR-Petten to neutron fluences relevant for the SNR-300 service conditions post-irradiation tensile and creep tests (up to 10,000 hrs rupture time) were performed in the temperature range 723 K to 923 K. All heats are embrittled by irradiation resulting in reduction of rupture times, creep strength and ultimate tensile strength. The considerable reduction is attributed to helium enhanced intergranular creep crack growth, which reduces the ductility and strength, but does not affect the creep rate. The variation of tensile and creep properties is large and independent of irradiation. The minimum derived creep strength in irradiated condition drops below the values expected in the ASME Code and VdTuV Blatt. In design and safety analyses the irradiation effect on creep properties must be accounted for with an appropriate reduction factor. The predictions given, have to be verified with long-term creep tests and parts of the SNR surveillance programme. 172 figs.; 17 refs.; 58 tables

Radar-based dynamic testing of the cable-suspended bridge crossing the Ebro River at Amposta, Spain

Energy Technology Data Exchange (ETDEWEB)

Gentile, Carmelo [Politecnico di Milano, Dept. of Architecture, Built environment and Construction engineering (ABC), Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Luzi, Guido [Centre Tecnòlogic de Telecomunicacions de Catalunya (CTTC), Division of Geomatics, Av. Gauss, 7 E-08860 Castelldefels (Barcelona) (Spain)

2014-05-27

Microwave remote sensing is the most recent experimental methodology suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. After a brief description of the radar measurement system, the paper addresses the application of microwave remote sensing to ambient vibration testing of a cable-suspended bridge. The investigated bridge crosses the Ebro River at Amposta, Spain and consists of two steel stiffening trusses and a series of equally spaced steel floor beams; the main span is supported by inclined stay cables and two series of 8 suspension cables. The dynamic tests were performed in operational conditions, with the sensor being placed in two different positions so that the response of both the steel deck and the arrays of suspension elements was measured. The experimental investigation confirms the simplicity of use of the radar and the accuracy of the results provided by the microwave remote sensing as well as the issues often met in the clear localization of measurement points.

Radar-based dynamic testing of the cable-suspended bridge crossing the Ebro River at Amposta, Spain

International Nuclear Information System (INIS)

Gentile, Carmelo; Luzi, Guido

2014-01-01

Microwave remote sensing is the most recent experimental methodology suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. After a brief description of the radar measurement system, the paper addresses the application of microwave remote sensing to ambient vibration testing of a cable-suspended bridge. The investigated bridge crosses the Ebro River at Amposta, Spain and consists of two steel stiffening trusses and a series of equally spaced steel floor beams; the main span is supported by inclined stay cables and two series of 8 suspension cables. The dynamic tests were performed in operational conditions, with the sensor being placed in two different positions so that the response of both the steel deck and the arrays of suspension elements was measured. The experimental investigation confirms the simplicity of use of the radar and the accuracy of the results provided by the microwave remote sensing as well as the issues often met in the clear localization of measurement points

Construction of the Chamagawa bridge; Chamagawabashi no seko

Energy Technology Data Exchange (ETDEWEB)

Kawado, A.; Okawa, M. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Yoshii, M.; Oda, I.

1997-09-30

The Chamagawa Bridge is a reinforced concrete fixed-arch bridge which is located at the northern end of Awaji Island, 1.5 km away from the Honshu-Shikoku linking large-scale Akashi Strait Bridge. This paper describes the design and construction of the bridge. Overhang construction method using cable stayed members was adopted. Against the tensile stress generated in the arch-ring under construction, reaction force was burdened with cable stayed columns, anchor blocks and ground anchors by regulating stress using cable stayed members and by resisting using PC steel rods arranging in the arch-ring. For the construction of arch-ring, a space was made for fabricating a specific large-scale movable working vehicle by the grounding support. Then, overhang construction was started. For the construction of overhang, construction of cable stayed members, regulation of stress, and tension of ground anchors were conducted with the construction of each block. The construction of linking block in the center was conducted by hanging support method after the specific large-scale movable working vehicle was taken to pieces. After the connection of arch-ring, tensile forces of cable stayed members and ground anchors were released. The bridge was completed in the down road in 1997. 1 ref., 21 figs., 6 tabs.

CRASH TEST AND EVALUATION OF RESTRAINED SAFETY-SHAPE CONCRETE BARRIERS ON CONCRETE BRIDGE DECK

Science.gov (United States)

2018-01-01

This research designed and tested a new portable concrete barrier that meets the performance of MASH TL-4 and can be used in temporary and permanent applications on bridge decks. Additionally, this new barrier system will minimize deflection, allowin...

78 FR 55337 - Buy America Waiver Notification

Science.gov (United States)

2013-09-10

... project in the State of Ohio. The MEP identified some domestic suppliers capable of casting part of the...'' class 150 cast steel gate valves for rehabilitation of the Oxbow Bridge project in the State of Ohio... (including protective coatings) that are permanently incorporated in a Federal-aid construction project. The...

Hybrid structure in civil engineering construction. Composite types of steel and concrete; Doboku bun`ya ni okeru fukugo kozo. Kozai to concrete no ittai keishiki

Energy Technology Data Exchange (ETDEWEB)

Sato, T. [JR Railway Technical Research Inst. Tokyo (Japan)

1995-03-30

In connection with hybrid structures in civil engineering construction, classification and application of composite types of steel and concrete are discussed. H steel embedded beam is a composite beam in which the H shape steel of the main beam is connected to rolled or welded H shape steel using cross beams. Composite structure columns are grouped into the composite column and the steel pipe concrete column. SRC piers are often adopted from the viewpoints of constraints for execution of works and vibration proof. Steel and concrete hybrid structure is a kind of structural system in which various kinds of materials such as steel, RC, or PC members are connected. The cable stayed bridge utilizes characteristics of steel and concrete effectively. For the piers of municipal expressway viaducts, there are executed cases of mixed structures which have RC, SRC columns for T shape piers and S structure for the bridges. SRC structure and composite columns are adopted often for structures of subway stations. 7 refs., 7 figs.

Comparative testing of radiographic testing, ultrasonic testing and phased array advanced ultrasonic testing non destructive testing techniques in accordance with the AWS D1.5 bridge welding code : [summary].

Science.gov (United States)

2014-02-01

To ensure that Florida bridges remain safe and structurally secure for their 50-year-plus service life, they are inspected regularly. For steel bridges, welds critical to the bridges integrity do not even leave the workshop unless they meet rigoro...

Effects of heat pipe cooling on permanent mold castings of aluminum alloys

International Nuclear Information System (INIS)

Zhang, C.; Mucciardi, F.; Gruzleski, J.E.

2002-01-01

The temperature distribution within molds is a critical parameter in determining the ultimate casting quality in permanent mold casting processes, so there is a considerable incentive to develop a more effective method of mold cooling. Based on this consideration, a novel, effective and controllable heat pipe has been successfully developed and used as a new method of permanent mold cooling. Symmetric step casting of A356 alloy have been produced in an experimental permanent mold made of H13 tool steel, which is cooled by such heat pipes. The experimental results show that heat pipes can provide extremely high cooling rates in permanent mold castings of aluminum. The dendrite arm spacing of A356 alloy is refined considerably, and porosity and shrinkage of the castings are redistributed by the heat pipe cooling. Moreover, the heat pipe can be used to determine the time when the air gap forms at the interface between the mold and the casting. The effect of heat pipe cooling on solidification time of castings of A356 alloy with different coating types is also discussed in this paper. (author)

The Selection of Bridge Materials Utilizing the Analytical Hierarchy Process

Science.gov (United States)

Robert L. Smith; Robert J. Bush; Daniel L. Schmoldt

1997-01-01

Effective decisions on the use of natural resources often require the input of many individuals. Determining how specific criteria affect the selection of materials can lead to better utilization of raw materials. Concrete, steel, and timber represent over 98% of the materials used for bridge construction in the United States. Highway officials must often consider...

Deterministic and Probabilistic Analysis of NPP Communication Bridge Resistance Due to Extreme Loads

Directory of Open Access Journals (Sweden)

Králik Juraj

2014-12-01

Full Text Available This paper presents the experiences from the deterministic and probability analysis of the reliability of communication bridge structure resistance due to extreme loads - wind and earthquake. On the example of the steel bridge between two NPP buildings is considered the efficiency of the bracing systems. The advantages and disadvantages of the deterministic and probabilistic analysis of the structure resistance are discussed. The advantages of the utilization the LHS method to analyze the safety and reliability of the structures is presented

Design and Analysis of Collapsible Scissor Bridge

Directory of Open Access Journals (Sweden)

Biro Mohamad Nabil Aklif

2018-01-01

Full Text Available Collapsible scissor bridge is a portable bridge that can be deployed during emergency state to access remote areas that are affected by disaster such as flood. The objective of this research is to design a collapsible scissor bridge which is able to be transported by a 4x4 vehicle and to be deployed to connect remote areas. The design is done by using Solidworks and numerical analysis for structural strength is conducted via ANSYS. The research starts with parameters setting and modelling. Finite element analysis is conducted to analyze the strength by determining the safety factor of the bridge. Kutzbach equation is also analyzed to ensure that the mechanism is able to meet the targeted degree of motion. There are five major components of the scissor structure; pin, deck, cross shaft and deck shaft. The structure is controlled by hydraulic pump driven by a motor for the motions. Material used in simulation is A36 structural steel due to limited library in ANSYS. However, the proposed material is Fiber Reinforced Polymer (FRP composites as they have a high strength to weight ratio. FRP also tends to be corrosion resistance and this characteristic is useful in flooded area.

High energy x-ray radiography and computed tomography of bridge pins

International Nuclear Information System (INIS)

Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

1999-01-01

Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL

Behaviour of Steel Fibre Reinforced Rubberized Continuous Deep Beams

Science.gov (United States)

Sandeep, MS; Nagarajan, Praveen; Shashikala, A. P.

2018-03-01

Transfer girders and pier caps, which are in fact deep beams, are critical structural elements present in high-rise buildings and bridges respectively. During an earthquake, failure of lifeline structures like bridges and critical structural members like transfer girders will result in severe catastrophes. Ductility is the key factor that influences the resistance of any structural member against seismic action. Structural members cast using materials having higher ductility will possess higher seismic resistance. Previous research shows that concrete having rubber particles (rubcrete) possess better ductility and low density in comparison to ordinary concrete. The main hindrance to the use of rubcrete is the reduction in compressive and tensile strength of concrete due to the presence of rubber. If these undesirable properties of rubcrete can be controlled, a new cementitious composite with better ductility, seismic performance and economy can be developed. A combination of rubber particles and steel fibre has the potential to reduce the undesirable effect of rubcrete. In this paper, the effect of rubber particles and steel fibre in the behaviour of two-span continuous deep beams is studied experimentally. Based on the results, optimum proportions of steel fibre and rubber particles for getting good ductile behaviour with less reduction in collapse load is found out.

Design, Prototyping, and Analysis of a Novel Modular Permanent Magnet Transverse Flux Disk Generator

DEFF Research Database (Denmark)

Hosseini, Seyedmohsen; Moghani, Javad Shokrollahi; Ershad, Nima Farrokhzad

2011-01-01

by circular flat shaped Nd-Fe-B permanent magnets. First, a typical low power generator is designed, and then partially optimized. The optimization objective is to find an inner radius which maximizes the power factor, the output power to mass ratio and the efficiency. The generator equivalent circuit......This paper presents the design, prototyping, and analysis of a novel modular transverse flux permanent magnet disk generator. The disk-shaped structure simplifies the construction procedure by using laminated steel sheets. To reduce output harmonics, the excitation of the generator is done...... parameters are computed by three dimensional finite element analyses. The simulation results show that the power factor of the proposed structure is considerably greater than the power factor previously reported for other transverse flux permanent magnet generator structures. To verify the simulation results...

Design of Portable Bridge of Material Access on 8 m Level

International Nuclear Information System (INIS)

Sitompul, Aristarkus

2000-01-01

Base on the planning to increase of the working capability of the working capability of the rabbit system facility, the design of mentioned portable bridge on access has been done. Using the designed installation the transportation of the middle and high active samples from the isotop cell to the scanning room will be easy to be done. The design has been done by using the maximum actual load. Determination of maximum actual load, determination of maximum actual load, and also the chosen steel shape dimension compliance with ASTM standard. The installation required 2 peaces of W 6 x 12 steel beam by 111.82 inches in length, 4 peaces W 6 x 12 steel beam by 47.25 i n length and a peace of steel plate by 111.82 x 47.25 x 0,394 . This paper concluded that this design is feasible to be fabricated

Fatigue in Steel Structures under Random Loading

DEFF Research Database (Denmark)

Agerskov, Henning

1999-01-01

types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel with a yield stress of ~ 360-410 MPa or high-strength steel with a yield stress of ~ 810-1010 MPa. The fatigue tests and the fracture mechanics analyses......Fatigue damage accumulation in steel structures under random loading is studied. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part of the investigation, fatigue test series have been carried through on various...... have been carried out using load histories, which are realistic in relation to the types of structures studied, i.e. primarily bridges, offshore structures and chimneys. In general, the test series carried through show a significant difference between constant amplitude and variable amplitude fatigue...

THE STEEL EUROPEAN STOCK MARKET EFFICIENCY

Directory of Open Access Journals (Sweden)

Viorica CHIRILA

2015-12-01

Full Text Available Testing the hypothesis of informational efficiency is a permanent preoccupation of researchers because the theories and the models of modern finance are based on it. This paper presents the results obtained after testing the efficiency hypothesis, in the weak form, for the European stock market of the companies that belong to the economic steel sub-sector. Following the use of both linear and non-linear tests of autocorrelation of returns we can conclude that the European stock market in the economic steel sub-sector is inefficient from an informational point of view and the investors in these stocks may obtain better results than those of the European market in general.

Bridge condition assessment based on long-term strain monitoring

Science.gov (United States)

Sun, LiMin; Sun, Shouwang

2011-04-01

In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

Directory of Open Access Journals (Sweden)

Xuewei Wang

2017-01-01

Full Text Available In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM, and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

Science.gov (United States)

2018-01-01

Corrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural ...

Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

OpenAIRE

Franchetti Paolo; Frizzarin Michele; Leonardi Andrea; Zeni Fabio

2015-01-01

A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention ...

The morphology and formation mechanism of pearlite in steels

Energy Technology Data Exchange (ETDEWEB)

Zhang, M.-X., E-mail: Mingxing.Zhang@uq.edu.au [Division of Materials, School of Engineering, University of Queensland, St. Lucia, Queensland 4072 (Australia); Kelly, P.M. [Division of Materials, School of Engineering, University of Queensland, St. Lucia, Queensland 4072 (Australia)

2009-06-15

A number of morphological features of pearlite were revealed through scanning electron microscopy using deeply etched specimens. These include cementite branching, bridging, gaps, holes and curvature. The presence of cementite thin films or networks along the austenite grain boundaries in eutectoid steel and at the interface between pearlite and proeutectoid ferrite in hypoeutectoid steel is another characteristic of pearlite. Furthermore, ferrite thin films surrounding the proeutectoid cementite in hypereutectoid steels are also observed. Hence, it is considered that in hypoeutectoid steels the nucleus for pearlite is a film of cementite rather than the expected proeutectoid ferrite and, similarly, in hypereutectoid steels pearlite forms from a ferrite film rather than from proeutectoid cementite. Convergent beam Kikuchi line diffraction was used to accurately determine the orientation relationships between pearlitic constituents and parent austenite in a Hadfields steel. The results show that neither the pearlitic ferrite nor the cementite is crystallographically related to the austenite grain into which the pearlite was growing and to that into which it was not growing. In addition, a new orientation relationship between pearlitic cementite and ferrite in the Hadfield steel was also observed.

D0 Silicon Upgrade: End Calorimeter Transfer Bridge Design and Installation Procedures

International Nuclear Information System (INIS)

Stredde, H.J.

1991-01-01

The North Endcap Calorimeter (NEC) is to be moved from the clean room to the north sidewalk in preparation for the final installation on the DO detector center beam. In order to make this move, the cable bridge must be 'flattened' and the NEC lifted to move over it. The detector is moved west, approximately 24 feet, while the moveable counting house remains stationary. This movement allows the cable bridge to 'flatten' i.e. become horizontal. The cable bridge lowering is steadied and stabilized by 7.5 ton hoist mounted on the moveable counting house. By moving the detector to lower the bridge, a vacancy has been created in the pit that must be filled to the level of the clean room rail elevation. This filler will consist of concrete shield blocks, stacked in two rows. These rows are spaced appropriately to match the wheel base of the EC transporter. A steel plate is placed on top of each row of shield blocks and leveled to the elevation of the clean room rails. Steel plates will be installed and leveled on the north sidewalk similar to those used on the south sidewalk for the CC installation. These plates are used as rails for the Hilman rollers, bearing surfaces for shim blocks used during lifting and anchors for holding the transporter extension units and the transfer bridge. After the plates are installed, the transfer bridge is put in place, spanning the cable bridge, shimmed and leveled. The transporter extension units are positioned next to the transfer bridge on the north sidewalk. With the completion of this prep work, the actual transfer of the NEC from the clean room can begin. The NEC is pulled from the clean room with the same mechanism (cyl. and chain) that was used for the CC and the pull anchor point will be located at the end of the concrete blocks. The NEC will come out of the north west door in the clean room and move along the temporary rail plates in the pit until it is in line with the transfer bridge. At this point the NEC is ready to be

Seismic Behavior of Fatigue-Retrofitted Steel Frame Piers

Directory of Open Access Journals (Sweden)

Kinoshita K.

2013-01-01

Full Text Available Fatigue retrofit works have been conducted on severely fatigue damaged beam-to-column connections of existing steel frame bridge piers in Japan. It is clear that retrofit works provides additional stiffness but the significance on the seismic behavior of steel frame piers is not clear. Since fatigue retrofit works have become prevalent, the effect of fatigue retrofit works on the seismic behavior of steel frame piers need to be understood. The objective of this study is therefore to investigate these effects of the retrofit work, especially installation of bolted splices, which is the most common technique. Elasto-plastic finite element earthquake response analyses were carried out. It is shown that the existence of bolted splices may increase seismic demand on the piers when plastic hinge zone is located on the beam. In addition, longer bolted splices using low yield strength steel are proposed to overcome this problem and are shown to give beneficial effects.

Truck-based mobile wireless sensor networks for the experimental observation of vehicle–bridge interaction

International Nuclear Information System (INIS)

Kim, Junhee; Lynch, Jerome P; Lee, Jong-Jae; Lee, Chang-Geun

2011-01-01

Heavy vehicles driving over a bridge create a complex dynamic phenomenon known as vehicle–bridge interaction. In recent years, interest in vehicle–bridge interaction has grown because a deeper understanding of the phenomena can lead to improvements in bridge design methods while enhancing the accuracy of structural health monitoring techniques. The mobility of wireless sensors can be leveraged to directly monitor the dynamic coupling between the moving vehicle and the bridge. In this study, a mobile wireless sensor network is proposed for installation on a heavy truck to capture the vertical acceleration, horizontal acceleration and gyroscopic pitching of the truck as it crosses a bridge. The vehicle-based wireless monitoring system is designed to interact with a static, permanent wireless monitoring system installed on the bridge. Specifically, the mobile wireless sensors time-synchronize with the bridge's wireless sensors before transferring the vehicle response data. Vertical acceleration and gyroscopic pitching measurements of the vehicle are combined with bridge accelerations to create a time-synchronized vehicle–bridge response dataset. In addition to observing the vehicle vibrations, Kalman filtering is adopted to accurately track the vehicle position using the measured horizontal acceleration of the vehicle and positioning information derived from piezoelectric strip sensors installed on the bridge deck as part of the bridge monitoring system. Using the Geumdang Bridge (Korea), extensive field testing of the proposed vehicle–bridge wireless monitoring system is conducted. Experimental results verify the reliability of the wireless system and the accuracy of the vehicle positioning algorithm

Seismic assessment of a multi-span steel railway bridge in Turkey based on nonlinear time history

Science.gov (United States)

Yılmaz, Mehmet F.; Çağlayan, Barlas Ö.

2018-01-01

Many research studies have shown that bridges are vulnerable to earthquakes, graphically confirmed by incidents such as the San Fernando (1971 USA), Northridge (1994 USA), Great Hanshin (1995 Japan), and Chi-Chi (1999 Taiwan) earthquakes, amongst many others. The studies show that fragility curves are useful tools for bridge seismic risk assessments, which can be generated empirically or analytically. Empirical fragility curves can be generated where damage reports from past earthquakes are available, but otherwise, analytical fragility curves can be generated from structural seismic response analysis. Earthquake damage data in Turkey are very limited, hence this study employed an analytical method to generate fragility curves for the Alasehir bridge. The Alasehir bridge is part of the Manisa-Uşak-Dumlupınar-Afyon railway line, which is very important for human and freight transportation, and since most of the country is seismically active, it is essential to assess the bridge's vulnerability. The bridge consists of six 30 m truss spans with a total span 189 m supported by 2 abutments and 5 truss piers, 12.5, 19, 26, 33, and 40 m. Sap2000 software was used to model the Alasehir bridge, which was refined using field measurements, and the effect of 60 selected real earthquake data analyzed using the refined model, considering material and geometry nonlinearity. Thus, the seismic behavior of Alasehir railway bridge was determined and truss pier reaction and displacements were used to determine its seismic performance. Different intensity measures were compared for efficiency, practicality, and sufficiency and their component and system fragility curves derived.

Classical and Modern Design Solutions in Conceptual Design of a Pedestrian Bridge over Vistula River in Cracow

Science.gov (United States)

Ryż, Karol; Pańtak, Marek

2017-10-01

In the paper the design concept of the steel pedestrian bridge over Vistula river in Cracow, Poland has been characterised. The footbridge was designed as a truss structure with steel pipes, Warren truss configuration, arched bottom chord and spans 15.5+120.0+15.5 m. Intensive tourist traffic around the Wawel Castle in Cracow, directed towards the historic Kazimierz district, Wawel Hill and the Old Town Market Place requires the creation of a bridge structure over the Vistula River that will meet both the communication and recreation functions. An additional aim was to design a structure which architectural form will not unduly and negatively interfere in the environment and will join the technical capabilities of the XXI century with the charm of nearby historic buildings.

Dynamic Behaviour of Different Types of Cable-Stayed Bridges Due to Earthquake Loads

Directory of Open Access Journals (Sweden)

Alireza Mirza Goltabar Roshan

2016-12-01

Full Text Available Construction of large-scale structures has been considered as one of the human's main achievements.  With their suitable view and high economical aspects, High-strength steel cables have been developed for analysis and erection of cable-stayed bridges in light of high speed development in computer technology. This type of bridges, while providing different behavior due to cable flexibility, has been recognized as one of the most practical choices for mid to large span bridges. This paper studies the non-linear dynamic behavior of cable bridges and the effect of some parameters (such as cable arrangement and shape of pylon on them. For this purpose, CSI Bridge software with the direct integration method of dynamic analysis has been used and the behavior of structure under different earthquake components has been analyzed for various conditions of cable arrangements and pylon shapes. Results indicate that the most suitable behavior would be for cable bridges with H-shape pylons arranged in series and also with A-shape pylons in radial arrangement.

Progress in thermomechanical control of steel plates and their commercialization

Science.gov (United States)

Nishioka, Kiyoshi; Ichikawa, Kazutoshi

2012-01-01

The water-cooled thermomechanical control process (TMCP) is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates. PMID:27877477

Progress in thermomechanical control of steel plates and their commercialization

Directory of Open Access Journals (Sweden)

Kiyoshi Nishioka and Kazutoshi Ichikawa

2012-01-01

Full Text Available The water-cooled thermomechanical control process (TMCP is a technology for improving the strength and toughness of water-cooled steel plates, while allowing control of the microstructure, phase transformation and rolling. This review describes metallurgical aspects of the microalloying of steel, such as niobium addition, and discusses advantages of TMCP, for example, in terms of weldability, which is reduced upon alloying. Other covered topics include the development of equipment, distortions in steel plates, peripheral technologies such as steel making and casting, and theoretical modeling, as well as the history of property control in steel plate production and some early TMCP technologies. We provide some of the latest examples of applications of TMCP steel in various industries such as shipbuilding, offshore structures, building construction, bridges, pipelines, penstocks and cryogenic tanks. This review also introduces high heat-affected-zone toughness technologies, wherein the microstructure of steel is improved by the addition of fine particles of magnesium-containing sulfides and magnesium- or calcium-containing oxides. We demonstrate that thanks to ongoing developments TMCP has the potential to meet the ever-increasing demands of steel plates.

Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports : [summary].

Science.gov (United States)

2014-05-01

In the past, bridges were aligned normal to crossing roads or obstacles in order to simplify bridge construction. However, the continuing expansion of the interstate system has challenged engineers to provide more horizontal clearance, reduce right-o...

Integrated Monitoring System for Durability Assessment of Concrete Bridges

Directory of Open Access Journals (Sweden)

Cristian-Claudiu Comisu

2005-01-01

Full Text Available An ageing and deteriorating bridge stock presents the bridge owners with the growing challenge of maintaining the structures at a satisfactory level of safety, performance and aesthetic appearance within the allocated budgets. This task calls for optimized bridge management based on efficient methods of selecting technical and economical optimal maintenance and rehabilitation strategies. One of the crucial points in the assessment of the current condition and future development and performance. Selecting the optimal maintenance and rehabilitation strategy within the actual budget is a key point in bridge management for which an accurate assessment of performance and deterioration rate is necessary. For this assessment, the use of integrated monitoring system has several advantages compared to the traditional approach of scattered visual inspections combined with occasional on site testing with portable equipment and laboratory testing of collected samples. For this reason, attention is more focusing on the development of permanent integrated monitoring system for durability assessment of concrete bridges. It is estimated that with the implementation of such integrated monitoring systems, it should be possible to reduce the operating costs of inspections and maintenance by 25% and the operator of the structures will be able to take protective actions before damaging processes start. This paper indentifies the main bridge owner requirements to integrated monitoring systems and outlines how monitoring systems may be used for performance and deterioration rate assessment to establish a better basis for selecting the optimal maintenance and rehabilitation strategy.

Mechanical Behaviour and Durability of FRP-to-steel Adhesively-bonded Joints

NARCIS (Netherlands)

Jiang, X.

2013-01-01

During the last two decades, fiber-reinforced polymer (FRP) bridge decks have been increasingly used as a competitive alternative for wood, concrete and orthotropic steel decks, due to their various advantages: light-weight, good corrosion resistance, low maintenance cost and rapid installation for

Consideration on extradosed prestressed concrete road bridge; Dorokyo ni okeru daihenshin PC keburu kyo

Energy Technology Data Exchange (ETDEWEB)

Ogawa, A.; Honma, A. [Japan Highway Public Corp., Tokyo (Japan)

1997-03-31

The details of the investigation on the Odawara Blue Way Bridge for which extradosed type is employed are provided, and a report is made about the situation of the study on the future construction of the 2nd Tomei-Meishin Expressway. The extradosed PC bridge is considered to have intermediate structural characteristics of those of the conventional beam bridge and PC cable stayed bridge, and is expected to be applied to bridges having approximately from 100 to 200m span. The features of the extradosed PC bridge is outlined. Approximately 1/35 beam height on the intermediate support and 1/10 main tower height against the center span are considered to be proper. PC steel products can be used efficiently because stress fluctuation of diagonals and the load sharing rate of the diagonal member are less than those of the PC cable stayed bridge and safety factor similar to that of general internal cable can be adopted. Construction works for the main tower and the diagonal member are easy due to low height of the main tower, and the bridge is advantageous also in the maintenance control because no beam is required. 5 refs., 8 figs., 2 tabs.

Study on load test of 100m cross-reinforced deck type concrete box arch bridge

Science.gov (United States)

Shi, Jing Xian; Cheng, Ying Jie

2018-06-01

Found in the routine quality inspection of highway bridge that many vertical fractures on the main beam (10mT beam) of the steel reinforced concrete arch bridge near the hydropower station. In order to grasp the bearing capacity of this bridge under working conditions with cracks, the static load and dynamic load test of box arch bridge are carried out. The Midas civil theory is calculated by using the special plate trailer - 300 as the calculation load, and the deflection and stress of the critical section are tested by the equivalent cloth load in the test vehicle. The pulsation test, obstacles and no obstacle driving test were carried out. Experimental results show that the bridge under the condition of the test loads is in safe condition, main bearing component of the strength and stiffness meet the design requirements, the crack width does not increase, in the process of loading bridge overall work performance is good.

Seismic assessment of a multi-span steel railway bridge in Turkey based on nonlinear time history

Directory of Open Access Journals (Sweden)

M. F. Yılmaz

2018-01-01

Full Text Available Many research studies have shown that bridges are vulnerable to earthquakes, graphically confirmed by incidents such as the San Fernando (1971 USA, Northridge (1994 USA, Great Hanshin (1995 Japan, and Chi-Chi (1999 Taiwan earthquakes, amongst many others. The studies show that fragility curves are useful tools for bridge seismic risk assessments, which can be generated empirically or analytically. Empirical fragility curves can be generated where damage reports from past earthquakes are available, but otherwise, analytical fragility curves can be generated from structural seismic response analysis. Earthquake damage data in Turkey are very limited, hence this study employed an analytical method to generate fragility curves for the Alasehir bridge. The Alasehir bridge is part of the Manisa–Uşak–Dumlupınar–Afyon railway line, which is very important for human and freight transportation, and since most of the country is seismically active, it is essential to assess the bridge's vulnerability. The bridge consists of six 30 m truss spans with a total span 189 m supported by 2 abutments and 5 truss piers, 12.5, 19, 26, 33, and 40 m. Sap2000 software was used to model the Alasehir bridge, which was refined using field measurements, and the effect of 60 selected real earthquake data analyzed using the refined model, considering material and geometry nonlinearity. Thus, the seismic behavior of Alasehir railway bridge was determined and truss pier reaction and displacements were used to determine its seismic performance. Different intensity measures were compared for efficiency, practicality, and sufficiency and their component and system fragility curves derived.

An evaluation of alternative stator lamination materials for a high-speed, 1.5 MW, permanent magnet generator

NARCIS (Netherlands)

Paulides, J.J.H.; Jewell, G.W.; Howe, D.

2004-01-01

The influence of the choice of stator lamination material on the iron loss in a high speed, high power permanent magnet generator, which is interfaced to a DC link via a simple bridge rectifier, is investigated. The rating of the generator is representative of machines which would be employed in

Numerical investigation of out-of-plane secondary stress in the web of floor beam of steel truss bridge. Ko torasu kyo no yukageta web ni shojiru mengai niji oryoku no suchiteki gen'in bunseki

Energy Technology Data Exchange (ETDEWEB)

Sato, T. (Kisarazu National College of Technology, Chiba (Japan)); Kuranishi, S. (Kanto Gakuin Univ., Kanagawa (Japan). Faculty of Engineering); Nakazawa, M. (Tohoku Univ., Sendai (Japan). Faculty of Enginering)

1994-06-20

Comparative investigation of numerical analysis results of out-of-plane secondary stress caused in a cross beam web around scallop before reinforcement and around cutting portion of vertical stiffeners after reinforcement was carried out. In case of steel truss bridge, there exists difference in axial thrust between outside stringers which continue through a cross beam, and it was revealed that this axial thrust was the main factor which causes partial bending stress in a cross beam web plate. When the lower end of vertical stiffeners is not connected to a cross beam foot flange considering of welding, out-of-plane secondary stress was caused partially in a cross beam web plate around scallop, because of the difficult to transmit adjoining stringers axial thrust difference directly to foot flange. In case of the actual analysis, cross beam web plate around cutting portion of vertical stiffeners causes partial out-of-plane secondary stress in web plate, due to being pressed partially by comparatively high stiffness vertical stiffeners. When repair and reinforcement of steel road truss bridge are carried out, it is necessary to take close attention specially on the structure of the parts in which outside stringers is connected to cross beam. 18 refs., 16 figs.

Implementation of straight and curved steel girder erection design tools construction : summary.

Science.gov (United States)

2010-11-05

Project 0-5574 Curved Plate Girder Design for Safe and Economical Construction, resulted in the : development of two design tools, UT Lift and UT Bridge. UT Lift is a spreadsheet-based program for analyzing : steel girders during lifting while ...

Development of a wireless monitoring system for fracture-critical bridges

Science.gov (United States)

Fasl, Jeremiah; Samaras, Vasilis; Reichenbach, Matthew; Helwig, Todd; Wood, Sharon L.; Potter, David; Lindenberg, Richard; Frank, Karl

2011-04-01

This paper provides a summary of ongoing research sponsored by the National Institute of Standards and Technology (NIST) that seeks to improve inspection practices for steel bridges by providing the technology and methodology for real-time monitoring. In order to reduce the time and cost of installing a monitoring system, the research team elected to use wireless communications within the sensor network. The investigation considered both IEEE 802.11 and IEEE 802.15.4 communications protocols and identified the latter as more practical for bridge monitoring applications. Studies were conducted to investigate possible improvements in the network performance using high-gain antennas. Results from experiments conducted outside and on bridges with different antennas are presented in this paper. Although some benefits were observed using high-gain antennas, the inconsistent performance and higher cost relative to the current stock, omni-directional antennas does not justify their use.

Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

Directory of Open Access Journals (Sweden)

Ding Youliang

2016-01-01

Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

The Influence of the Track Axis Curvature at Railway Filler-Beam Deck Bridges

Directory of Open Access Journals (Sweden)

Răzvan Marian Stănescu

2016-06-01

Full Text Available The article presents a comparative study between the simplified method calculation proposed by the prescriptions of design codes and the analysis with the FEM program LUSAS [1], regarding the influence of the curvature of the track axis at railway bridges with steel beams embedded in concrete.

Evaluation of corrosion of prestressing steel in concrete using non-destructive techniques

International Nuclear Information System (INIS)

Ali, M.G.; Maddocks, A.R.

2003-01-01

Use of high strength steel in pre-stressed concrete structures has been in use in Australia for many decades. Highway bridges, among other structures, have extensively used pre-stress-ing and post-tensioning techniques. Although prestressing offers many competitive edges to it's traditional rival reinforced concrete, the consequence of damage to prestressing tendons could be catastrophic. Periodic visual inspections of prestressed concrete bridges throughout the world have demonstrated the growing problem of deterioration of prestressing steel as a result of corrosion. Early detection of damage to prestressing steel therefore is of paramount importance. Unfortunately no reliable and practical non-destructive evaluation technique has been available for assessing the condition of prestressing steel within concrete although a number of techniques appear promising. The following inspection methods have been highlighted in recent literature for their use as non-destructive inspection methods for prestressed concrete structures. In addition to the techniques discussed, a number of destructive, or invasive techniques also exist for determination of the corrosion status of prestressing tendons in prestressed structures. The following non-destructive techniques are discussed in some detail: Radiography; Computed Tomography; Surface Penetrating Radar; Impact Echo; Acoustic Emission Monitoring; Magnetic Field Disturbance Technique; Remnant Magnetism Method; Linear Polarisation Method; Electrical Resistance and Surface Potential Survey. The portability, limitations and use in Australia of these techniques are summarised in a table

Construction of a composite cable stayed bridge. Karnali river bridge in Nepal. Gosei shachokyo no kensetsu. Karnali kawa kyoryo

Energy Technology Data Exchange (ETDEWEB)

Maeda, M.; Nakamura, K.; Shimodoi, H.; Amako, M.; Miyoshi, S.; Haruta, M.; Okada, S.; Kuroki, S. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

1994-07-20

The present report reports the construction of Karnali River Bridge in Nepal by Kawasaki Heavy Industries, Ltd. The present bridge is a composite cable stayed bridge, two-spanned with a main span length of 325m and side span length of 175m. Having an about 125m-high single tower, it is 11.3m in breadth and 3m in main truss height. The main truss is supported by both faces of 30 cables per face, i.e., 60 cables. (Each of both main and side spans has 15 cables per face.) The design and construction are described with the following their itemization: design (bending moment properties in the erected system, composite structure of main truss and stress analysis at the time of erection). Wind resisting measures (measures for the wind resistant stability at the time of erection of both tower and main truss cantilever). Fabrication and transportation of steel structural members. Fabrication of precast floor plates (concrete mixing, and fabrication and curing of floor plates). Construction of tower foundation (tremie concrete and air concrete). Erection of upper structures (erection of tower, both main and side spans, and accuracy management). 14 figs., 4 tabs.

Structural properties and out-of-plane stability of roller bent steel arches

NARCIS (Netherlands)

Spoorenberg, R.C.

2011-01-01

In contemporary architecture the use of steel arches has seen a significant increase. They are applied in buildings and large span bridges, combining structural design with architectural merits. For arches lacking lateral support (or freestanding arches) the out-of-plane structural stability

In-service performance evaluation and monitoring of a hybrid composite beam bridge system : final report.

Science.gov (United States)

2017-10-01

The hybrid composite beam (HCB) technology has been presented as a system for short and medium span beam bridges as an alternative to traditional materials such as concrete and steel. An HCB consists of a concrete tied arch encased in a fiber reinfor...

Structural behavior of concrete box bridge using embedded FBG sensors

Science.gov (United States)

Chung, Wonseok; Kang, Donghoon

2012-04-01

For the structural monitoring of railway bridges, electromagnetic interference (EMI) is a significant problem as modern railway lines are powered by high-voltage electric power feeding systems. Fiber optic sensing systems are free from EMI and have been successfully applied in civil engineering fields. This study presents the application of fiber Bragg grating (FBG)-based sensing systems to precast concrete box railway bridges. A 20 m long full-scale precast concrete box railway girder was fabricated and tested in order to identify its static performance. The experimental program involved the measurement of the nonlinear static behavior until failure. Multiplexed FBG strain sensors were embedded along the length of steel rebar and a strain-induced wavelength shift was measured in order to monitor internal strains. The measured values from the FBG-based sensors are compared with the results using electric signal-based sensors. The results show that the FBG sensing system is promising and can improve the efficiency of structural monitoring for modern railway bridges.

Vibration monitoring of long bridges and their expansion joints and seismic devices

Directory of Open Access Journals (Sweden)

Islami Kleidi

2015-01-01

Full Text Available This paper presents a number of recently installed Structural Health Monitoring (SHM systems: a on a 2km double suspension bridge; b on a long railway viaduct that has experienced cracking; and c on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, designed in collaboration with structure owners and design engineers, includes damage detection on expansion joints of suspension bridges, crack analysis and correlation with accelerations of high-speed trains, and high-frequency performance monitoring of seismic devices. These case studies, based on both static and dynamic approaches, demonstrate the usefulness and ease of use of such systems, and the enormous gains in efficiency they offer.

Magnetic Nondestructive Testing Techniques of Constructional Steel

Directory of Open Access Journals (Sweden)

Xiong Er-gang

2016-01-01

Full Text Available Steel is a kind of ferromagnetic material, which is extensively applied in such fields as buildings, bridges, railways, machines and lifeline engineering etc. Those engineering structures built of constructional steel will unavoidably experience some damages during their service lifetime, thus which will influence the distribution regularity of internal forces in structures, result in over-stresses, cause the local failure of structures, and even lead to collapse of the whole structure. Therefore, it is a pressing topic to study how to directly evaluate the real-time stressed states of structural members, damages and steel characteristics in present structural health monitoring and diagnosing fields. And the achievements of this research will be of theoretical significance and of application value of engineering. This paper summarizes varieties of new magnetic nondestructive testing techniques used in constructional steel, respectively investigates the testing principles, characteristics and application for the magnetic Barkhausen noise technique, magnetic acoustic emission technique, magnetic flux leakage technique, magnetic memory technique and magnetic absorption technique, and points out the problems present in the application of these new techniques to actual testing and the further research objective.

Seismic fragility curves of bridge piers accounting for ground motions in Korea

Science.gov (United States)

Nguyen, Duy-Duan; Lee, Tae-Hyung

2018-04-01

Korea is located in a slight-to-moderate seismic zone. Nevertheless, several studies pointed that the peak earthquake magnitude in the region can be reached to approximately 6.5. Accordingly, a seismic vulnerability evaluation of the existing structures accounting for ground motions in Korea is momentous. The purpose of this paper is to develop seismic fragility curves for bridge piers of a steel box girder bridge equipped with and without base isolators based on a set of ground motions recorded in Korea. A finite element simulation platform, OpenSees, is utilized to perform nonlinear time history analyses of the bridges. A series of damage states is defined based on a damage index which is expressed in terms of the column displacement ductility ratio. The fragility curves based on Korean motions were thereafter compared with the fragility curves generated using worldwide earthquakes to assess the effect of the two ground motion groups on the seismic fragility curves of the bridge piers. The results reveal that both non- and base-isolated bridge piers are less vulnerable during the Korean ground motions than that under worldwide earthquakes.

Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

Directory of Open Access Journals (Sweden)

P. T. C. Mendes

Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

The Fatigue Behavior of Steel Structures under Random Loading

DEFF Research Database (Denmark)

Agerskov, Henning

2009-01-01

of the investigation, fatigue test series with a total of 540 fatigue tests have been carried through on various types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel or high-strength steel. The fatigue tests......Fatigue damage accumulation in steel structures under random loading has been studied in a number of investigations at the Technical University of Denmark. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part...... and the fracture mechanics analyses have been carried out using load histories, which are realistic in relation to the types of structures studied, i.e. primarily bridges, offshore structures and chimneys. In general, the test series carried through show a significant difference between constant amplitude...

Test-bed for the remote health monitoring system for bridge structures using FBG sensors

Science.gov (United States)

Lee, Chin-Hyung; Park, Ki-Tae; Joo, Bong-Chul; Hwang, Yoon-Koog

2009-05-01

This paper reports on test-bed for the long-term health monitoring system for bridge structures employing fiber Bragg grating (FBG) sensors, which is remotely accessible via the web, to provide real-time quantitative information on a bridge's response to live loading and environmental changes, and fast prediction of the structure's integrity. The sensors are attached on several locations of the structure and connected to a data acquisition system permanently installed onsite. The system can be accessed through remote communication using an optical cable network, through which the evaluation of the bridge behavior under live loading can be allowed at place far away from the field. Live structural data are transmitted continuously to the server computer at the central office. The server computer is connected securely to the internet, where data can be retrieved, processed and stored for the remote web-based health monitoring. Test-bed revealed that the remote health monitoring technology will enable practical, cost-effective, and reliable condition assessment and maintenance of bridge structures.

Macroscopic Floquet topological crystalline steel and superconductor pump

Science.gov (United States)

Rossi, Anna M. E. B.; Bugase, Jonas; Fischer, Thomas M.

2017-08-01

The transport of a macroscopic steel sphere and a superconducting sphere on top of two-dimensional periodic magnetic patterns is studied experimentally and compared with the theory and with experiments on topological transport of magnetic colloids. Transport of the steel and superconducting sphere is achieved by moving an external permanent magnet on a closed loop around the two-dimensional crystal. The transport is topological, i.e., the spheres are transported by a primitive unit vector of the lattice when the external magnet loop winds around specific directions. We experimentally determine the set of directions the loops must enclose for nontrivial transport of the spheres into various directions. We show that the loops can be used to sort steel and superconducting spheres. We show that the topological transport is robust with respect to the scale of the system and therefore speculate on its down scalability to the molecular scale.

Numerical Analysis of Damage Iinitiation and Development in Bends of Steel Pipelines

NARCIS (Netherlands)

Swart, A.E.

2010-01-01

Gasses and fluids are transported via an extensive infrastructure of steel pipelines. In the design of pipeline systems the use of elbows (pipe bends) is important because their flexibility makes them able to sustain significant deformations. These bends can be subjected to permanent deformations

CorTen steel: a solution to atmospheric degradation in acid and marine environments

OpenAIRE

Ruiz Galende, Patricia

2018-01-01

35 p.: il. [EN] Weathering steel has a special resistance against the atmospheric corrosion through the formation of a protective layer. This layer is formed, among others, due to the reaction of some alloy elements present in the steel with reactive species, such as sulphur and nitrogen oxides and/or chlorides, which are present in the environment. For that reason, it is a widely used material in outdoor structures (facades, bridges) and it is in vogue among modern sculptors because this ...

A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.

OpenAIRE

Srinu Duvvada; Manmadha Kumar B

2014-01-01

In this paper, a buck half-bridge DC-DC converter is used as a single-stage power factor correction (PFC) converter for feeding a voltage source inverter (VSI) based permanent magnet brushless DC motor (BLDC) drive. The front end of this PFC converter is a diode bridge rectifier (DBR) fed from single-phase AC mains. The BLDC is used to drive a compressor load of an air conditioner through a three-phase VSI fed from a controlled DC link voltage. The speed of the compressor is controlled to ach...

The Cost Analysis of Corrosion Protection Solutions for Steel Components in Terms of the Object Life Cycle Cost

Directory of Open Access Journals (Sweden)

Kowalski Dariusz

2017-09-01

Full Text Available Steel materials, due to their numerous advantages - high availability, easiness of processing and possibility of almost any shaping are commonly applied in construction for carrying out basic carrier systems and auxiliary structures. However, the major disadvantage of this material is its high corrosion susceptibility, which depends strictly on the local conditions of the facility and the applied type of corrosion protection system. The paper presents an analysis of life cycle costs of structures installed on bridges used in the road lane conditions. Three anti-corrosion protection systems were considered, analyzing their essential cost components. The possibility of reducing significantly the costs associated with anti-corrosion protection at the stage of steel barriers maintenance over a period of 30 years has been indicated. The possibility of using a new approach based on the life cycle cost estimation in the anti-corrosion protection of steel elements is presented. The relationship between the method of steel barrier protection, the scope of repair, renewal work and costs is shown. The article proposes an optimal solution which, while reducing the cost of maintenance of road infrastructure components in the area of corrosion protection, allows to maintain certain safety standards for steel barriers that are installed on the bridge.

The Cost Analysis of Corrosion Protection Solutions for Steel Components in Terms of the Object Life Cycle Cost

Science.gov (United States)

Kowalski, Dariusz; Grzyl, Beata; Kristowski, Adam

2017-09-01

Steel materials, due to their numerous advantages - high availability, easiness of processing and possibility of almost any shaping are commonly applied in construction for carrying out basic carrier systems and auxiliary structures. However, the major disadvantage of this material is its high corrosion susceptibility, which depends strictly on the local conditions of the facility and the applied type of corrosion protection system. The paper presents an analysis of life cycle costs of structures installed on bridges used in the road lane conditions. Three anti-corrosion protection systems were considered, analyzing their essential cost components. The possibility of reducing significantly the costs associated with anti-corrosion protection at the stage of steel barriers maintenance over a period of 30 years has been indicated. The possibility of using a new approach based on the life cycle cost estimation in the anti-corrosion protection of steel elements is presented. The relationship between the method of steel barrier protection, the scope of repair, renewal work and costs is shown. The article proposes an optimal solution which, while reducing the cost of maintenance of road infrastructure components in the area of corrosion protection, allows to maintain certain safety standards for steel barriers that are installed on the bridge.

Numerical thermal analysis of the vertical external partition made as the frame thin-walled steel structure

Directory of Open Access Journals (Sweden)

Major Maciej

2017-01-01

Full Text Available The article presents numerical thermal analysis of the vertical external partitions made in the lightweight steel framing technology. Steel posts that perform the structural role lead to the formation of linear thermal bridges and have a negative effect on the level of thermal transmittance U. Therefore, optimal solutions are being explored for such technologies. One of the solutions is to use perforated Thermo sections. The effect of perforated Thermo sections on energy loss was verified through comparison to the wall made of solid sections. Furthermore, the calculations analysed the effect of linear thermal bridges that are formed on wall connections in the corner. Computer simulation was employed to emphasize the significant differences in the temperature distribution in both analysed wall structures that resulted from constructional solutions.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

Science.gov (United States)

Wu, Lai-Yi

2015-01-01

Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature. PMID:26451387

COMPARATIVE ANALYSIS OF THE BEHAVIOR OF COAXIAL AND FRONTAL COUPLINGS – WITH PERMANENT MAGNETS – IN HIGH TEMPERATURE ENVIRONMENTS

Directory of Open Access Journals (Sweden)

Marcel Oanca

2004-12-01

Full Text Available This paper presents a comparative analysis of the behavior of coaxial and frontal couplings – with permanent magnets – in high temperature environments specific to iron and steel industry. The comparative analysis is made at the level of the specific forces developed in the most difficult environments. The maximum temperature was limited for reasons of thermal stability of the Nd-Fe-B permanent magnets. In this context it was studied, by the help of the PDE-ase soft that uses the finite element method, the way magnetic induction modifies, the specific forces developed and the distribution of temperature within the coaxial and frontal couplers with permanent magnets, for variations of the distance between the magnets (air gap within the limits 2-20 mm.

Demonstration and Validation of a Composite Grid Reinforcement System for Bridge Decks

Science.gov (United States)

2016-09-01

presence of chlorides from road salts that can pene- trate into the concrete deck and cause corrosion of standard steel reinforcement. Installation of the... Corrosion of Metal and Alloys – Corrosivity of Atmospheres – Classification, Determination and Estimation.” Geneva, Switzerland: International Standards...one year), an atmospheric corrosion test rack, (equipped with sensors to monitor corrosion and chlorides were in- serted in the bridge deck), and

Experiment on interface separation detection of concrete-filled steel tubular arch bridge using accelerometer array

Science.gov (United States)

Pan, Shengshan; Zhao, Xuefeng; Zhao, Hailiang; Mao, Jian

2015-04-01

Based on the vibration testing principle, and taking the local vibration of steel tube at the interface separation area as the study object, a real-time monitoring and the damage detection method of the interface separation of concrete-filled steel tube by accelerometer array through quantitative transient self-excitation is proposed. The accelerometers are arranged on the steel tube area with or without void respectively, and the signals of accelerometers are collected at the same time and compared under different transient excitation points. The results show that compared with the signal of compact area, the peak value of accelerometer signal at void area increases and attenuation speed slows down obviously, and the spectrum peaks of the void area are much more and disordered and the amplitude increases obviously. whether the input point of transient excitation is on void area or not is irrelevant with qualitative identification results. So the qualitative identification of the interface separation of concrete-filled steel tube based on the signal of acceleration transducer is feasible and valid.

Comparative life cycle cost assessment of painted and hot-dip galvanized bridges.

Science.gov (United States)

Rossi, B; Marquart, S; Rossi, G

2017-07-15

The study addresses the life cycle cost assessment (LCCA) of steel bridges, focusing on the maintenance activities and the maintenance scenario. Firstly, the unit costs of maintenance activities and their durability (i.e. the time between two activities) are evaluated. Pragmatic data are provided for the environment category C4 and for three activities: Patch Up, Overcoating and Remove & Replace. A comparative LCCA for a typical hypothetic steel girder bridge is carried out, either painted or hot-dip galvanized (HDG), in the environmental class C4. The LCC versus the cumulated life is provided for both options. The initial cost of the steel unpainted option is only 50.3% of the HDG option. It is shown that after 'Overcoating' occurring at 18.5 years, the total Net Present Value (NPV) of the painted option surpasses that of the HDG option. A sensitivity analysis of the NPV to the cost and service life parameters, the escalation and discount rates is then performed. The discount and escalation rates, considerably influences the total LCC, following a non-linear trend. The total LCC decreases with the discount rate increasing and, conversely, increases with the escalation rate increasing. Secondly, the influence of the maintenance scenario on the total LCC is assessed based on a probabilistic approach. A permutation of the three independent maintenance activities assumed to occur six times over the life of the bridge is considered and a probability of occurrence is associated to each unique scenario. The most probable scenarios are then classified according to their NPV or achieved service life. This approach leads to the definition of a cost-effective maintenance scenario i.e. the scenario, within all the considered permutations, that has the minimum LCC in a range of lifespan. Besides, the probabilistic analysis also shows that, whatever the scenario, the return on investment period ranges between 18.5 years and 24.2 years. After that period, the HDG option becomes

Flexible concrete link slabs used as expansion joints in bridge decks

DEFF Research Database (Denmark)

Lárusson, Lárus Helgi; Fischer, Gregor

2011-01-01

of water through the expansion joint and subsequent corrosion of girders and girder bearings. Investigations on joint-less superstructures using conventional steel reinforcement in so-called concrete link slabs indicate improved performance and economic feasibility. However, this concept requires...... relatively large amounts of steel reinforcement for crack control purposes and consequently provides a relatively large flexural stiffness and negative moment capacity at the joint between the spans. These contradicting requirements and effects in existing replacement concepts for damaged mechanical bridge...... joints are currently unresolved. In the proposed system described in this paper, a ductile cement-based composite section reinforced with Glass Fiber Reinforced Polymers (GFRP) replaces the damaged expansion joint. The combination of this ductile concrete together with corrosion resistant GFRP...

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

Golden Gate Bridge response: a study with low-amplitude data from three earthquakes

Science.gov (United States)

Çelebi, Mehmet

2012-01-01

The dynamic response of the Golden Gate Bridge, located north of San Francisco, CA, has been studied previously using ambient vibration data and finite element models. Since permanent seismic instrumentation was installed in 1993, only small earthquakes that originated at distances varying between ~11 to 122 km have been recorded. Nonetheless, these records prompted this study of the response of the bridge to low amplitude shaking caused by three earthquakes. Compared to previous ambient vibration studies, the earthquake response data reveal a slightly higher fundamental frequency (shorter-period) for vertical vibration of the bridge deck center span (~7.7–8.3 s versus 8.2–10.6 s), and a much higher fundamental frequency (shorter period) for the transverse direction of the deck (~11.24–16.3 s versus ~18.2 s). In this study, it is also shown that these two periods are dominant apparent periods representing interaction between tower, cable, and deck.

Flexural and Shear Behavior of FRP Strengthened AASHTO Type Concrete Bridge Girders

Directory of Open Access Journals (Sweden)

Nur Yazdani

2016-01-01

Full Text Available Fiber-reinforced polymers (FRP are being increasingly used for the repair and strengthening of deteriorated or unsafe concrete structures, including structurally deficient concrete highway bridges. The behavior of FRP strengthened concrete bridge girders, including failure modes, failure loads, and deflections, can be determined using an analytical finite element modeling approach, as outlined in this paper. The differences in flexural versus shear FRP strengthening and comparison with available design guidelines are also beneficial to design professionals. In this paper, a common AASHTO type prestressed concrete bridge girder with FRP wrapping was analyzed using the ANSYS FEM software and the ACI analytical approach. Both flexural and shear FRP applications, including vertical and inclined shear strengthening, were examined. Results showed that FRP wrapping can significantly benefit concrete bridge girders in terms of flexure/shear capacity increase, deflection reduction, and crack control. The FRP strength was underutilized in the section selected herein, which could be addressed through decrease of the amount of FRP and prestressing steel used, thereby increasing the section ductility. The ACI approach produced comparable results to the FEM and can be effectively and conveniently used in design.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

Directory of Open Access Journals (Sweden)

You-Liang Ding

2015-01-01

Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

The Effect of Type and Volume Fraction (Vf) of Steel Fiber on the Mechanical Properties of Self-Compacting Concrete

DEFF Research Database (Denmark)

Ghanbarpour, S.; Mazaheripour, H.; Mirmoradi, S. H.

2010-01-01

is to investigate the effects of type and volume fraction of steel fiber on the compressive strength, split tensile strength, flexural strength and modulus of elasticity of steel fiber reinforced self-compacting concrete (SFRSCC). Design/methodology/approach – For this purpose, Micro wire and Wave type steel fibers......Purpose – Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their propagation, and improve several characteristics and properties of the SCC. The purpose of this paper...... – It was found that, inclusion of steel fibers significantly affect the split tensile and flexural strength of SCC accordance with type and vf. Besides, mathematical expressions were developed to estimate the flexural, modulus of elasticity and split tensile strength of SFRSCCs regarding of compressive strength...

Stabilization of magnet assemblies of permanent magnet sodium flowmeters used in fast breeder reactors

Energy Technology Data Exchange (ETDEWEB)

Rajan, K.K., E-mail: kkrajan@igcar.gov.in; Vijayakumar, G.

2014-08-15

Highlights: • Stabilization procedure for ALNICO-5 permanent magnet material is evolved. • Effect of time and temperature on ALNICO-5 assembly is determined. • Suitability of ALNICO-5 flowmeters at high temperatures is established. • Temperature coefficient of flux density is determined. - Abstract: Permanent magnet flow meters (PMFMs) are used to measure the sodium flow in sodium cooled Fast Breeder Reactor Circuits. Prototype fast breeder reactor (PFBR) which is under construction at Kalpakkam is a 500 MWe, sodium cooled, pool type reactor. Sodium flow measurement in various loops of the reactor is of prime importance from operational and safety point of view. To measure the flow of electrically conducting liquid sodium, in primary and secondary circuit pipe lines of PFBR, permanent magnet flow meters are used. PMFM is a non-invasive device, which works on the principle of generation of motional EMF by magnetic forces exerted on the charges in a moving conductor. Flowmeters of different pipe sizes ranging from 10 mm to 200 mm pipe diameter are required for PFBR. Long term performance of the flowmeters mainly depends on stability of permanent magnets used in flowmeters to generate constant magnetic field in stainless steel (SS) pipes. This paper describes the effects of time and temperature on permanent magnet assemblies made of ALNICO-V used in PFBR flowmeters. The stabilization methodology for ALNICO-V permanent magnet assemblies is evolved and established. Loss of magnetic field strength with respect to time and temperatures is determined by experiments and found negligible.

Fatigue life prediction for a cold worked T316 stainless steel

International Nuclear Information System (INIS)

Manjoine, M.J.

1983-01-01

Permanent damage curves of initiation-life and propagation-life which predict the fatigue life of specimens of a cold-worked type 316 stainless steel under complex strain-range histories were generated by a limited test program. Analysis of the test data showed that fatigue damage is not linear throughout life and that propagation life is longer than initiation-life at high strain ranges but is shorter at low strain ranges. If permanent damage has been initiated by prior history and/or fabrication, propagation to a given life can occur at a lower strain range than that estimated from the fatigue curves for constant CSR. (author) [pt

Strengthening of a railway bridge with NSMR and CFRP tubes

DEFF Research Database (Denmark)

Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

2008-01-01

Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10 ....... Sensors on bars and tubes display proofs of utilization of the CFRP while displacement sensors and strain gauges on the steel reinforcement due to the small loads in the service limit state show minor effect....

Long-term behaviour of a steel-concrete composite railway bridge deck

OpenAIRE

STAQUET, S; TAILHAN, JL; ESPION, B

2005-01-01

A prefabricated, composite and prestressed railway bridge deck has been instrumented in June 2000 with strain gages and vibrating wire extensometers. The purpose of this paper is to report on the comparison between strains recorded in situ up to four years with values computed within the framework of an original time-dependent analysis base on the evolution of the degree of hydration and the internal relative humidity in concrete. These fundamental parameters used in the proposed model to com...

Temperature compensation of NdFeB permanent magnets

International Nuclear Information System (INIS)

Kim, S.H.; Doose, C.

1997-01-01

Permanent magnet blocks of NdFeB have a relatively high maximum energy product. Because of its relatively low Curie temperature, however, NdFeB has a large temperature coefficient for its residual induction. The temperature coefficients of the relative magnetic fields (ΔB/B)/ΔT in the air gap of NdFeB dipole magnets were reduced from -1.1 x 10 -3 /c to less than 2 x 10 -5 /degree C under operating temperatures of ± 6 C. This was achieved passively by using 1.25-mm-thick strips of 30%-Ni-Fe alloy as flux shunts for the NdFeB blocks. The magnets with soft-steel poles and flux-return yokes were assembled and measured in a temperature-controlled environment

Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

Directory of Open Access Journals (Sweden)

Franchetti Paolo

2015-01-01

Full Text Available A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention of rehabilitation of the bridge led to a reinforcement of the existing hinges with the coupling of new metallic devices: new tongue and groove hinges were applied, that by one side allow the horizontal displacements and rotation, by the other side strongly reduce the relative vertical displacements of the two parts of the bridge. A dynamic test campaign was set up in order to assess the effectiveness of the intervention. The principal dynamic parameters were calculated and analysed with respect to the intervention that was realized. The tests clearly showed the effectiveness of the intervention, and helped the designer to have a better understanding of the structural behaviour of the bridge.

47 CFR 80.331 - Bridge-to-bridge communication procedure.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

The analysis of the permanent magnet motor using the new magnetic field analysis

International Nuclear Information System (INIS)

Shimoji, Hiroyasu; Enokizono, Masato; Todaka, Takashi

2002-01-01

In this paper iron loss analysis of the permanent magnet motor considering anisotropy of magnetic material is carried out. Recently the magnetic material can be measured using of vector quantity technique. Non-oriented silicon steel sheets for the iron core material have the anisotropy. Therefore, it is necessary to carry out the analysis considering the anisotropy of the magnetic material. We used the magnetic field analysis, which consider the anisotropy by combining finite element method with the E and S (Enokizono and Soda) modeling. (Author)

Creep and shrinkage effects on integral abutment bridges

Science.gov (United States)

Munuswamy, Sivakumar

Integral abutment bridges provide bridge engineers an economical design alternative to traditional bridges with expansion joints owing to the benefits, arising from elimination of expensive joints installation and reduced maintenance cost. The superstructure for integral abutment bridges is cast integrally with abutments. Time-dependent effects of creep, shrinkage of concrete, relaxation of prestressing steel, temperature gradient, restraints provided by abutment foundation and backfill and statical indeterminacy of the structure introduce time-dependent variations in the redundant forces. An analytical model and numerical procedure to predict instantaneous linear behavior and non-linear time dependent long-term behavior of continuous composite superstructure are developed in which the redundant forces in the integral abutment bridges are derived considering the time-dependent effects. The redistributions of moments due to time-dependent effects have been considered in the analysis. The analysis includes nonlinearity due to cracking of the concrete, as well as the time-dependent deformations. American Concrete Institute (ACI) and American Association of State Highway and Transportation Officials (AASHTO) models for creep and shrinkage are considered in modeling the time dependent material behavior. The variations in the material property of the cross-section corresponding to the constituent materials are incorporated and age-adjusted effective modulus method with relaxation procedure is followed to include the creep behavior of concrete. The partial restraint provided by the abutment-pile-soil system is modeled using discrete spring stiffness as translational and rotational degrees of freedom. Numerical simulation of the behavior is carried out on continuous composite integral abutment bridges and the deformations and stresses due to time-dependent effects due to typical sustained loads are computed. The results from the analytical model are compared with the

Fatigue of cable anchorage of large cable stayed bridge; Daikibo shachokyo cable teichaku kozo no hiro

Energy Technology Data Exchange (ETDEWEB)

Endo, T.; Matsumoto, T. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Tsukahara, H. [Yokogawa Bridge Corp., Tokyo (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan)

1995-10-21

Design considerations such as design schemes, the assemblage and welding of steel plates, and safety for fatigue of welded connections have to be taken for the cable anchorages of the steel cable stayed bridges. In this study, two full scale models, which have different shape of box anchorages welded to the web of the main girder, were made to investigate fatigue characteristics as well as assemblage of plate and gelding details. Finite element analyses for both test models and actual bridges here carried out to compare stress distribution. It was confirmed that the assemblage and welding of both types of box anchorage were attainable kith required quality and accuracy. According to the fatigue test, fatigue cracks originated from the weldings of the bearing plate to which the load from cable socket applied directly were caused by out-of-plane bending of the bearing plate. It was proved that the slight modifications of the details around the bearing plate resulted in sufficient fatigue strength in both types of anchorage. 1 ref., 23 figs., 2 tabs.

Vibration measurement-based simple technique for damage detection of truss bridges: A case study

Directory of Open Access Journals (Sweden)

Sudath C. Siriwardane

2015-10-01

Full Text Available The bridges experience increasing traffic volume and weight, deteriorating of components and large number of stress cycles. Therefore, assessment of the current condition of steel railway bridges becomes necessary. Most of the commonly available approaches for structural health monitoring are based on visual inspection and non-destructive testing methods. The visual inspection is unreliable as those depend on uncertainty behind inspectors and their experience. Also, the non-destructive testing methods are found to be expensive. Therefore, recent researches have noticed that dynamic modal parameters or vibration measurement-based structural health monitoring methods are economical and may also provide more realistic predictions to damage state of civil infrastructure. Therefore this paper proposes a simple technique to locate the damage region of railway truss bridges based on measured modal parameters. The technique is discussed with a case study. Initially paper describes the details of considered railway bridge. Then observations of visual inspection, material testing and in situ load testing are discussed under separate sections. Development of validated finite element model of the considered bridge is comprehensively discussed. Hence, variations of modal parameters versus position of the damage are plotted. These plots are considered as the main reference for locating the damage of the railway bridge in future periodical inspection by comparing the measured corresponding modal parameters. Finally the procedure of periodical vibration measurement and damage locating technique are clearly illustrated.

[Mineral trioxide aggragate pulpotomy for the treatment of immature permanent teeth with irreversible pulpitis: a preliminary clinical study].

Science.gov (United States)

Peng, Chufang; Zhao, Yuming; Yang, Yuan; Qin, Man

2015-12-01

To evaluate the preliminary clinical effect of mineral trioxide aggragate (MTA) pulpotomy on immature permanent teeth with irreversible pulpitis. Twenty-six immature permanent teeth with irreversible pulpitis were recuited from Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology. These teeth were treated with partial or full pulpotomy according to the condition of pulp bleeding. MTA was used as pulp capping material. Patients were recalled periodically after the treatment. Clinical and radiographic effects were evaluated. At one year follow-up, 20 teeth were evaluated as healed or healing, 2 teeth were evaluated as failure and 4 teeth were dropped out. The success rate was considered 91% (20/22). A dentinal bridge was radiographcally observed underneath the pulpotomy site in 13 teeth(65%, 13/20). MTA pulpotomy is an effective method for the treatment of immature permanent teeth with irreversible pulpitis. But further research with longer follow up period is required.

Strain features and condition assessment of orthotropic steel deck cable-supported bridges subjected to vehicle loads by using dense FBG strain sensors

Science.gov (United States)

Wei, Shiyin; Zhang, Zhaohui; Li, Shunlong; Li, Hui

2017-10-01

Strain is a direct indicator of structural safety. Therefore, strain sensors have been used in most structural health monitoring systems for bridges. However, until now, the investigation of strain response has been insufficient. This paper conducts a comprehensive study of the strain features of the U ribs and transverse diaphragm on an orthotropic steel deck and proposes a statistical paradigm for crack detection based on the features of vehicle-induced strain response by using the densely distributed optic fibre Bragg grating (FBG) strain sensors. The local feature of strain under vehicle load is highlighted, which enables the use of measurement data to determine the vehicle loading event and to make a decision regarding the health status of a girder near the strain sensors via technical elimination of the load information. Time-frequency analysis shows that the strain contains three features: the long-term trend item, the short-term trend item, and the instantaneous vehicle-induced item (IVII). The IVII is the wheel-induced strain with a remarkable local feature, and the measured wheel-induced strain is only influenced by the vehicle near the FBG sensor, while other vehicles slightly farther away have no effect on the wheel-induced strain. This causes the local strain series, among the FBG strain sensors in the same transverse locations of different cross-sections, to present similarities in shape to some extent and presents a time delay in successive order along the driving direction. Therefore, the strain series induced by an identical vehicle can be easily tracked and compared by extracting the amplitude and calculating the mutual ratio to eliminate vehicle loading information, leaving the girder information alone. The statistical paradigm for crack detection is finally proposed, and the detection accuracy is then validated by using dense FBG strain sensors on a long-span suspension bridge in China.

Pilot Study for Investigating the Cyclic Response of the Recentering Bridge Bearing System Combined with the Friction Damper

Directory of Open Access Journals (Sweden)

Jong Wan Hu

2016-01-01

Full Text Available The bridge bearing is one of the component members which provide resting supports between piers and decks. The bridge bearing is intended to control longitudinal movement caused by traffic flow and thermal expansion, thereby reducing stress concentration. In high seismicity area, the bridge bearing has been utilized as the base isolation system to mitigate acceleration transferred from the ground. Although the existing bridge bearing installed between superstructure and substructure provides extra flexibility to the base of the entire structure, considerable permanent deformation occurs due to lack of recentering capacity after earthquake. It is required to spend extra cost for repairing impaired parts. The bridge bearings integrated with superelastic shape memory alloy (SMA devices used for upgrading the recentering effect into the friction damper are proposed in this study. The refined finite element (FE analyses are introduced to reproduce the response of such new structures under cyclic loading condition. The bridge bearing systems that maintain uniform recentering capability are designed with various friction coefficients so as to examine energy dissipation and residual deformation through FE analyses. After observing FE analysis results, optimal design for the recentering bridge bearing system will be proposed to take advantage of energy dissipation and self-centering capacity.

Direct current force sensing device based on compressive spring, permanent magnet, and coil-wound magnetostrictive/piezoelectric laminate.

Science.gov (United States)

Leung, Chung Ming; Or, Siu Wing; Ho, S L

2013-12-01

A force sensing device capable of sensing dc (or static) compressive forces is developed based on a NAS106N stainless steel compressive spring, a sintered NdFeB permanent magnet, and a coil-wound Tb(0.3)Dy(0.7)Fe(1.92)/Pb(Zr, Ti)O3 magnetostrictive∕piezoelectric laminate. The dc compressive force sensing in the device is evaluated theoretically and experimentally and is found to originate from a unique force-induced, position-dependent, current-driven dc magnetoelectric effect. The sensitivity of the device can be increased by increasing the spring constant of the compressive spring, the size of the permanent magnet, and/or the driving current for the coil-wound laminate. Devices of low-force (20 N) and high-force (200 N) types, showing high output voltages of 262 and 128 mV peak, respectively, are demonstrated at a low driving current of 100 mA peak by using different combinations of compressive spring and permanent magnet.

Treatment of nitridation by microwave post discharge plasma in an AISI 4140 steel

International Nuclear Information System (INIS)

Medina F, A.; Rodriguez L, V.; Zamora R, L.; Oseguera P, J.

1998-01-01

The objective of this work is to determine through X-ray diffraction, microhardness measurement and scanning electron microscopy those main operation parameters of the microwave post discharge treatment (temperature of treatment, gas mixture and permanence time) nitriding an AISI 4140 steel and to characterize the compact layer of nitrides formed during the treatment. (Author)

Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

Directory of Open Access Journals (Sweden)

Zheheng Chen

2015-01-01

Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

History of Connecticut's short-term strain program for evaluation of steel bridges : July 2009.

Science.gov (United States)

2009-07-01

Non-destructive strain monitoring has been used for two decades on Connecticuts bridges to : supplement visual field inspections. These studies have addressed a wide range of problems, : including fatigue cracking in diaphragm connections, cracked...

Development of a facility for fabricating nuclear waste canisters from radioactively contaminated steel

International Nuclear Information System (INIS)

Logan, J.A.; Larsen, M.M.

1986-01-01

This paper describes design of a facility and processes capable of using radioactively contaminated waste steel as the principal raw material for fabricating stainless steel canisters to be used for disposal of nuclear high-level waste. By such action, expenditure (i.e., permanent loss to society) of thousands of tons of uncontaminated chromium and nickel to fabricate such canisters can be avoided. Moreover, the cost and risks involved in disposing of large accumulations of radioactively contaminated steel as low-level radioactive waste (LLRW), that would otherwise be necessary, can also be avoided. The canister fabrication processes (involving centrifugal casting) described herein have been tested and proven for this application. The performance characteristics of stainless steel canisters so fabricated have been tested and agreed to by the organizations that have been involved in this development work (Battelle Memorial Institute, DuPont, EGandG and the Savannah River Laboratory) as equivalent to the performance characteristics of canisters fabricated of uncontaminated wrought stainless steel. It is estimated that the production cost for fabricating canisters by the methods described will not differ greatly from the production cost using uncontaminated wrought steel, and the other costs avoided by not having to dispose of the contaminated steel as LLRW could cause this method to produce the lowest ultimate overall costs

Wind-induced cable vibrations and countermeasures of cables of PC cable-stayed bridge. PC syachokyo keburu no kaze ni yoru shindo to sono taisaku

Energy Technology Data Exchange (ETDEWEB)

Yoneda, M. (Kawada Industries Inc., Tokyo (Japan))

1994-05-01

In recent years, long span of cable-stayed bridges is remarkable. The wind-induced cable vibration called as line vibration and wake galloping was given as an important problem not only in the steel cable-stayed bridges but also in the PC cable-stayed bridges. The technical engineers in design of the cable-stayed bridges have many times to confront the problems on the vibration control of cables, it is considered that sufficient understand of the wind-induced vibration and countermeasures for cables of the PC cable-stayed bridges is necessary. Many reports on the countermeasure examples and trend of vibration control centred on cables of the cable-stayed bridges have been published. In this paper, the wind-induced vibration of cables in the cable-stayed bridges was reviewed, the examples of countermeasures of vibration control on cables in the PC cable-stayed bridges was mainly introduced. The remaining tasks and future prospects on vibration control of the PC cable-stayed bridges were described. 14 refs., 13 figs., 4 tabs.

Practical assessment of magnetic methods for corrosion detection in an adjacent precast, prestressed concrete box-beam bridge

Science.gov (United States)

Fernandes, Bertrand; Titus, Michael; Nims, Douglas Karl; Ghorbanpoor, Al; Devabhaktuni, Vijay Kumar

2013-06-01

Magnetic methods are progressing in the detection of corrosion in prestressing strands in adjacent precast, prestressed concrete box-beam bridges. This study is the first field trial of magnetic strand defect detection systems on an adjacent box-beam bridge. A bridge in Fayette County, Ohio, which was scheduled for demolition, was inspected. Damage to prestressed box-beams is often due to corrosion of the prestressing strands. The corroded strands show discontinuities and a reduced cross-sectional area. These changes, due to corrosion, are reflected in the magnetic signatures of the prestressing steel. Corrosion in the prestressing steel was detected using two magnetic methods, namely the 'magnetic flux leakage' (MFL) and the 'induced magnetic field'. The purpose of these tests was to demonstrate the ability of the magnetic methods to detect hidden corrosion in box-beams in the field and tackle the logistic problem of inspecting box-beams from the bottom. The inspections were validated by dissecting the bottom of the box-beams after the inspections. The results showed that the MFL method can detect hidden corrosion and strand breaks. Both magnetic field methods were also able to estimate corrosion by detecting the effective cross-sectional area of the strand in sections of the beams. Thus, it was shown that the magnetic methods can be used to predict hidden corrosion in prestressing strands of box-beams.

Application of Classical Land Surveying Measurement Methods for Determining the Vertical Displacement of Railway Bridges

Science.gov (United States)

Gawronek, Pelagia; Makuch, Maria

2017-12-01

The classical measurements of stability of railway bridge, in the context of determining the vertical displacements of the object, consisted on precise leveling of girders and trigonometric leveling of controlled points (fixed into girders' surface). The construction elements, which were measured in two ways, in real terms belonged to the same vertical planes. Altitude measurements of construction were carried out during periodic structural stability tests and during static load tests of bridge by train. The specificity of displacement measurements, the type of measured object and the rail land surveying measurement conditions were determinants to define methodology of altitude measurement. The article presents compatibility of vertical displacements of steel railway bridge, which were developed in two measurement methods. In conclusion, the authors proposed the optimum concept of determining the vertical displacements of girders by using precise and trigonometric leveling (in terms of accuracy, safety and economy of measurement).

Application of Classical Land Surveying Measurement Methods for Determining the Vertical Displacement of Railway Bridges

Directory of Open Access Journals (Sweden)

Gawronek Pelagia

2017-12-01

Full Text Available The classical measurements of stability of railway bridge, in the context of determining the vertical displacements of the object, consisted on precise leveling of girders and trigonometric leveling of controlled points (fixed into girders' surface. The construction elements, which were measured in two ways, in real terms belonged to the same vertical planes. Altitude measurements of construction were carried out during periodic structural stability tests and during static load tests of bridge by train. The specificity of displacement measurements, the type of measured object and the rail land surveying measurement conditions were determinants to define methodology of altitude measurement. The article presents compatibility of vertical displacements of steel railway bridge, which were developed in two measurement methods. In conclusion, the authors proposed the optimum concept of determining the vertical displacements of girders by using precise and trigonometric leveling (in terms of accuracy, safety and economy of measurement.

Determining Time Variation of Cable Tension Forces in Suspended Bridges Using Time-Frequency Analysis

Directory of Open Access Journals (Sweden)

Gannon Stromquist-LeVoir

2018-01-01

Full Text Available A feasibility study was conducted to develop a novel method to determine the temporal changes of tensile forces in bridge suspender cables using time-frequency analysis of ambient vibration measurements. An analytical model of the suspender cables was developed to evaluate the power spectral density (PSD function of a cable with consideration of cable flexural stiffness. Discrete-time, short-time Fourier transform (STFT was utilized to analyze the recorded acceleration histories in both time and frequency domains. A mathematical convolution of the analytical PSD function and time-frequency data was completed to evaluate changes in cable tension force over time. The method was implemented using acceleration measurements collected from an in-service steel arch bridge with a suspended deck to calculate the temporal variation in cable forces from the vibration measurements. The observations served as proof of concept that the proposed method may be used for cable fatigue life calculations and bridge weigh-in-motion studies.

The permanent process

DEFF Research Database (Denmark)

Møller, Jesper; McCullagh, Peter

We extend the boson process first to a large class of Cox processes and second an even larger class of infinitely divisible point processes. Density and moment results are studied in detail. These results are obtained in closed form as weighted permanents, so the extension is called a permanent...... process. Temporal extensions and a particularly tractable case of the permanent process are also studied. Extensions of the ferminon process along similar lines, leading to so-called determinant processes, are discussed at the end. While the permanent process is attractive, the determinant process...

Precision rectifier detectors for ac resistance bridge measurements with application to temperature control systems for irradiation creep experiments

Energy Technology Data Exchange (ETDEWEB)

Duncan, M. G.

1977-05-01

The suitability of several temperature measurement schemes for an irradiation creep experiment is examined. It is found that the specimen resistance can be used to measure and control the sample temperature if compensated for resistance drift due to radiation and annealing effects. A modified Kelvin bridge is presented that allows compensation for resistance drift by periodically checking the sample resistance at a controlled ambient temperature. A new phase-insensitive method for detecting the bridge error signals is presented. The phase-insensitive detector is formed by averaging the magnitude of two bridge voltages. Although this method is substantially less sensitive to stray reactances in the bridge than conventional phase-sensitive detectors, it is sensitive to gain stability and linearity of the rectifier circuits. Accuracy limitations of rectifier circuits are examined both theoretically and experimentally in great detail. Both hand analyses and computer simulations of rectifier errors are presented. Finally, the design of a temperature control system based on sample resistance measurement is presented. The prototype is shown to control a 316 stainless steel sample to within a 0.15/sup 0/C short term (10 sec) and a 0.03/sup 0/C long term (10 min) standard deviation at temperatures between 150 and 700/sup 0/C. The phase-insensitive detector typically contributes less than 10 ppM peak resistance measurement error (0.04/sup 0/C at 700/sup 0/C for 316 stainless steel or 0.005/sup 0/C at 150/sup 0/C for zirconium).

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Cogging force investigation of a free piston permanent magnet linear generator

Science.gov (United States)

Abdalla, I. I.; Zainal, A. E. Z.; Ramlan, N. A.; Firmansyah; Aziz, A. R. A.; Heikal, M. R.

2017-10-01

Better performance and higher efficiency of the vehicles can be achieved by using free piston engine, in which the piston is connected directly to the linear generator and waiving of any mechanical means. The free piston engine has the ability to overcome or reduce many of the challenges, such as the carbon dioxide (CO2) emission and fossil fuel consumption. The cogging force produces undesired vibration and acoustic noise in the generator. However, the cogging force must be minimized as much as possible, in order to have a high performance. This paper studies the effects of ferromagnetic materials on the cogging force of the permanent magnet linear generator (PMLG) to be used in a free piston engine using nonlinear finite-element analysis (FEA) under ANSYS Maxwell. The comparisons have been established for the cogging force of the PMLG under various translator velocities and three different ferromagnetic materials for the stator core, namely, Silicon Steel laminations, Mild Steel and Somaloy. It has been shown that the PMLG with a stator core made of Somaloy has a lower cogging force among them. Furthermore, the induced voltage of the PMLG at different accelerations has been studied. It is found that the PMLG with Mild Steel and Somaloy, respectively give larger induced voltage. Moreover, as the translator speed increase the induced voltage increased.

Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

Science.gov (United States)

Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang

2016-11-01

Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization.

Impact of the Superpave hot mix asphalt properties on its permanent deformation behavior

Directory of Open Access Journals (Sweden)

Qasim Zahra

2018-01-01

Full Text Available In Iraq, the severity of rutting has increased in asphalt pavements possibly due to the increase in truck axle loads, tyre pressure, and high pavement temperature in summer. As of late, Superpave has been accounted as an enhanced system for performance based design, analysis of asphalt pavement performance prediction for asphalt concrete mixes. In this research the development of permanent deformation in asphalt concrete under repeated loadings was investigated, Wheel-Tracking apparatus has been used in a factorial testing program during which 44 slab samples were tested to simulate actual pavement. The objectives of the present research include; investigating the main factors affecting rutting in asphalt concrete mixture, quantifying the effect of SBS polymer and steel reinforcement on asphalt concrete mixtures in addition to studying the effect of variables on the asphalt concrete mixes against moisture sensitivity. It has been determined that that increasing of compaction temperature from 110 to 150°C will decrease the permanent deformation by 20.5 and 15.6 percent for coarse and fine gradation control asphalt mixtures, respectively. While the permanent deformation decreases by 21.3 percent when the compaction temperature is increased from 110 to 150°C for coarse gradation SBS modified asphalt mixtures.

GPS for structural health monitoring - case study on the Basarab overpass cable-stayed bridge

Science.gov (United States)

Lepadatu, Alexandru; Tiberius, Christian

2014-04-01

The Basarab cable-stayed bridge is a newly built structure in Bucharest, Romania, which was inaugurated in June 2011. Before the oficial opening, in order to assure its qualification for trafic, it had to pass several loading tests with convoys of trucks and trams. For this, besides a priori evaluation using the Finite Element Method (FEM), levelling and acceleration measurements were made to identify vertical displacements, as well as vibration frequencies of the bridge. The three-day loading trial of the bridge represented a good opportunity for setting-up a GPS campaign for structural monitoring of the Basarab bridge. Taking advantage of the redundancy obtained via simultaneous multi-sensor measurements, it was possible to compare and validate the GPS estimated displacements with both FEM and levelling. Moreover, the dynamic behaviour of the bridge during a dynamic loading test was evaluated using a 20 Hz GPS observation rate and validated afterwards with vibration frequency estimates from acceleration time series. Along with simulations (FEM) and laboratory tests, the in situ monitoring of a structure has a particular importance in establishing the safety of a newly-built structure. Furthermore, in some cases permanent monitoring is needed for safety and economic reasons, especially for strategic structures such as dams and bridges. GPS technology can satisfy this request due to its real-time processing capability and thus it can be looked upon as a new and promising tool for dynamic evaluation of engineering structures. In this contribution we have also assessed the performance of GPS with regard to accuracy and false alarm probability demands for the continuous monitoring of the Basarab cable-stayed bridge.

The Question of Decalage Between Object Permanence and Person Permanence

Science.gov (United States)

And Others; Jackson, Elaine

1978-01-01

Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

A Review of Permanent Magnet Stirring During Metal Solidification

Science.gov (United States)

Zeng, Jie; Chen, Weiqing; Yang, Yindong; Mclean, Alexander

2017-12-01

Rather than using conventional electromagnetic stirring (EMS) with three-phase alternating current, permanent magnet stirring (PMS), based on the use of sintered NdFeB material which has excellent magnetic characteristics, can be employed to generate a magnetic field for the stirring of liquid metal during solidification. Recent experience with steel casting indicates that PMS requires less than 20 pct of the total energy compared with EMS. Despite the excellent magnetic density properties and low power consumption, this relatively new technology has received comparatively little attention by the metal casting community. This paper reviews simulation modeling, experimental studies, and industrial trials of PMS conducted during recent years. With the development of magnetic simulation software, the magnetic field and associated flow patterns generated by PMS have been evaluated. Based on the results obtained from laboratory experiments, the effects of PMS on metal solidification structures and typical defects such as surface pinholes and center cavities are summarized. The significance of findings obtained from trials of PMS within the metals processing sector, including the continuous casting of steel, are discussed with the aim of providing an overview of the relevant parameters that are of importance for further development and industrial application of this innovative technology.

Essure Permanent Birth Control

Science.gov (United States)

... Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Print Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

AISI/DOE Technology Roadmap Program: Development of Cost-effective, Energy-efficient Steel Framing

Energy Technology Data Exchange (ETDEWEB)

Nader R. Elhajj

2003-01-06

Steel members in wall construction form a thermal bridge that interrupts the insulation layer of a wall. This causes higher rate of heat transfer by conduction through the wall framing than through other parts of the wall. One method to reduce the thermal bridging effect is to provide a break, such as insulating sheathing. A thermally efficient slit-web and stud was developed in this program to mitigate the conductivity of steel. The thermal performance of the slit-web stud was evaluated at Oak Ridge National Laboratory using hotbox testing. The thermal test results showed that the prototype slit-web stud performed 17% better than the solid-web stud, using R-13 fiber glass batts with exterior OSB sheathing and interior drywall. The structural behavior of this slit-web stud was evaluated in axial, bending, shear, shearwall, and stub-column tests. Test results indicated that the slitweb stud performed similarly or better than the solid-web stud in most structural performance characteristics investigated. Thus, the prototype slit-web stud has been shown to be thermally efficient, economiexecy viable, structurally sound, easily manufactured and usable in a range of residential installations.

Possibilities for the Reuse of Steel from Decommissioning. Selected Scenarios in the Process of Proposal and Evaluation of Manufacturing Processes for Conditional Released Steel and their Application in General and Nuclear Industry

International Nuclear Information System (INIS)

Bezak, P.; Daniska, V.; Ondra, F.; Necas, V.

2012-01-01

Conditional release of steels from NPP decommissioning enables controlled reuse of non-negligible volumes of steels. For proposal of scenarios for steel reuse, it is needed to identify and evaluate partial elementary activities of the whole process from conditional release of steels, manufacturing of various elements up to realisation of scenarios. For scenarios of reuse of conditionally released steel the products of steel, as steel reinforcements, rails, profiles and sheets for technical constructions such as bridges, tunnels, railways and other constructions which guarantee the long-term properties over the periods of 50-100 years are considered. The idea offers also the possibility for using this type of steel for particular technical constructions, directly usable in nuclear facilities. The paper presents the review of activities for manufacturing of various steel construction elements made from conditionally released steels and their use in general and also in the nuclear industry. As the starting material for manufacturing of steel elements ingots or just fragments of steel after dismantling in controlled area can be used. These input materials are re-melted in industrial facilities in order to achieve the required physical and chemical characteristics. Mostly used technique for manufacturing of the steel construction elements is rolling. As the products considered in scenarios for reuse of conditional released steels are bars for reinforcement concrete, rolled steel sheets and other rolled profiles. For use in the nuclear industry it offers the possibility for casting of thick-walled steel containers for long-term storage of high level radioactive components in integral storage and also assembly of stainless steel tanks for storing of liquid radioactive waste. Lists of elementary activities which are needed for manufacturing of selected steel elements are elaborated. These elementary activities are then the base for detailed safety evaluation of external

Demonstration and Validation of Two Coat High Performance Coating System for Steel Structures in Corrosive Environments

Science.gov (United States)

2016-12-01

Many of these steel buildings and equipment are tradi- tionally painted with an alkyd enamel or waterborne coating for a top coat. These paint systems...bridging minor cracks or for surfaces that have vi- bration and/or movement. These qualities are necessary in a barrier coat- ing primer for it to remain

Neighborhood level health risk assessment of lead paint removal activities from elevated steel bridges

Energy Technology Data Exchange (ETDEWEB)

Conway, R.F.; Cohen, J.T.; Bowers, T.

1999-07-01

The New York City Department of Transportation (NYCDOT) has adopted strict containment and monitoring procedures during paint removal activities on its bridges because of the increasing awareness about lead poisoning in children in urban environments and the potential risk of lead-based paint releases during those activities. NYCDOT owns nearly 800 bridges scattered throughout New York City. Before undertaking paint removal activities as part of its ongoing preventive maintenance and rehabilitation program, NYCDOT recently conducted an analysis to determine the public health risk posed to children living near them. The analysis the first of its kind to assess the actual public health risk potential during both routine operations and upset conditions, or accidental releases evaluated the total and incremental blood lead levels from paint removal activities on more than 5,000 children from 6 months to 6 years old. Increases in baseline blood lead levels were estimated using several models, including EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model. This model estimates steady-state blood lead levels in children, reflecting exposure to lead in multiple media over an extended period of time. Increases in lead exposure from paint removal activities in the area surrounding the bridges was estimated using EPA's Industrial Source Complex (ISC3) model to calculate ambient air and deposition levels. Potential releases from the containment and ancillary equipment used in the paint removal process were modeled based on different release scenarios ranging from routine operations to complete failure of containment. To estimate the paint removal activities' contribution to long-term exterior dust lead levels (and its related interior component), a stochastic simulation model was developed for each block in the study area.

Permanences GAG-EPA

CERN Document Server

GAC-EPA

2015-01-01

Le GAC organise chaque mois des permanences avec entretiens individuels. La prochaine permanence se tiendra le : Mardi 5 mai de 13 h 30 à 16 h 00 Salle de réunion de l’Association du personnel Les permanences suivantes auront lieu les mardis 2 juin, 1er septembre, 6 octobre, 3 novembre et 1er décembre 2015. Les permanences du Groupement des Anciens sont ouvertes aux bénéficiaires de la Caisse de pensions (y compris les conjoints survivants) et à tous ceux qui approchent de la retraite. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, auprès de l’Association du personnel, les documents nécessaires.

Digital image rectification tool for metrification of gusset plate connections in steel truss bridges.

Science.gov (United States)

2009-03-01

A method was developed to obtain dimensional data from photographs for analyzing steel truss gusset plate : connections. The method relies on a software application to correct photographic distortion and to scale the : photographs for analysis. The a...

The Impact of the HMCFRP Ratio on the Strengthening of Steel Composite I-Beams

Directory of Open Access Journals (Sweden)

E. Agcakoca

2012-01-01

Full Text Available Carbon fiber-reinforced polymer materials have become popular in the construction industry during the last decade for their ability to strengthen and retrofit concrete structures. The recent availability of high-modulus carbon fiber-reinforced polymer strips (HMCFRP has opened up the possibility of using this material in strengthening steel structures as well. The strips can be used in steel bridge girders and structures that are at risk of corrosion-induced cross-sectional losses, structural deterioration from aging, or changes in function. In this study, a set of bending experiments was performed on three types of steel beams reinforced with HMCFRP. The results were used to enhance a nonlinear finite element model built with ABAQUS software. The accuracy of the mathematical models for HMCFRP, epoxy, and steel profiles was compared with the experimental results, and the ability of HMCFRP to continue carrying load from the steel beams during rupture and postrupture scenarios was observed using numerical analysis. Using these verified finite element models, a parametric analysis was performed on the HMCFRP failure modes and the quantity to be used with IPE profile steel beams. The maximum amount of HMCFRP needed for strengthening was determined, and an upper limit for its use was calculated to avoid any debonding failure of the fiber material.

Steel fiber reinforced concrete behavior, modelling and design

CERN Document Server

Singh, Harvinder

2017-01-01

This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to d...

Railroad Bridges

Data.gov (United States)

Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

The consequences of recovery for the analysis of creep in steel structures

Energy Technology Data Exchange (ETDEWEB)

Bolton, J., E-mail: john.bolton@uwclub.ne [Rugby, Warks CV22 5HW (United Kingdom)

2010-05-15

Creep strain and recovery data for ferritic steels are used to construct a simple model that separates permanent strain from visco-elastic, recoverable strain. The model is shown to be consistent with data from tests under gradually varying stress. The implications of this model are examined for the design analysis of representative structures. It is shown that the modelling of recovery is important in some circumstances and not in others.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

Directory of Open Access Journals (Sweden)

Hatem M. Seliem

2015-04-01

The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

Using artificial neural networks in the design of orthotropic bridge decks

Directory of Open Access Journals (Sweden)

Ahmed Shamel Fahmy

2016-12-01

Full Text Available For orthotropic bridge decks a lot of progress has been made in the development of codes to aid in the design process, in addition to software tools for numerical analysis and design. However, professional software tools will not aid the designer in choosing a preliminary economic layout at the conceptual design stage. Designers would go through iterative, lengthy and expensive procedures to reach the best configuration. The present research provides a methodology to investigate the contingency of using artificial neural networks for conceptual design of orthotropic steel-deck bridge. A neural network model was trained with different combinations of dimensions, and eight types of safety checks were performed on all of them. The resulting network can predict whether the deck is safe or not. It is found that this approach for the selection of orthotropic deck dimensions is a better and cost-effective option compared with international codes or expert opinion.

Finite element simulation of photoacoustic fiber optic sensors for surface corrosion detection on a steel rod

Science.gov (United States)

Tang, Qixiang; Owusu Twumasi, Jones; Hu, Jie; Wang, Xingwei; Yu, Tzuyang

2018-03-01

Structural steel members have become integral components in the construction of civil engineering infrastructures such as bridges, stadiums, and shopping centers due to versatility of steel. Owing to the uniqueness in the design and construction of steel structures, rigorous non-destructive evaluation techniques are needed during construction and operation processes to prevent the loss of human lives and properties. This research aims at investigating the application of photoacoustic fiber optic transducers (FOT) for detecting surface rust of a steel rod. Surface ultrasonic waves propagation in intact and corroded steel rods was simulated using finite element method (FEM). Radial displacements were collected and short-time Fourier transform (STFT) was applied to obtain the spectrogram. It was found that the presence of surface rust between the FOT and the receiver can be detected in both time and frequency domain. In addition, spectrogram can be used to locate and quantify surface rust. Furthermore, a surface rust detection algorithm utilizing the FOT has been proposed for detection, location and quantification of the surface rust.

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

Natural Corrosion Inhibitors for Steel Reinforcement in Concrete — a Review

Science.gov (United States)

Raja, Pandian Bothi; Ghoreishiamiri, Seyedmojtaba; Ismail, Mohammad

2015-04-01

Reinforced concrete is one of the widely used construction materials for bridges, buildings, platforms and tunnels. Though reinforced concrete is capable of withstanding a large range of severe environments including marine, industrial and alpine conditions, there are still a large number of failures in concrete structures for many reasons. Either carbonation or chloride attack is the main culprit which is due to depassivation of reinforced steel and subsequently leads to rapid steel corrosion. Among many corrosion prevention measures, application of corrosion inhibitors play a vital role in metal protection. Numerous range of corrosion inhibitors were reported for concrete protection that were also used commercially in industries. This review summarizes the application of natural products as corrosion inhibitors for concrete protection and also scrutinizes various factors influencing its applicability.

Effect of Temperature Variation on Bond Characteristics between CFRP and Steel Plate

Directory of Open Access Journals (Sweden)

Shan Li

2016-01-01

Full Text Available In recent years, application of carbon fiber reinforced polymer (CFRP composite materials in the strengthening of existing reinforced concrete structures has gained widespread attention, but the retrofitting of metallic buildings and bridges with CFRP is still in its early stages. In real life, these structures are possibly subjected to dry and hot climate. Therefore, it is necessary to understand the bond behavior between CFRP and steel at different temperatures. To examine the bond between CFRP and steel under hot climate, a total of twenty-one double strap joints divided into 7 groups were tested to failure at constant temperatures from 27°C to 120°C in this paper. The results showed that the joint failure mode changed from debonding along between steel and adhesive interface failure to debonding along between CFRP and adhesive interface failure as the temperature increased beyond the glass transition temperature (Tg of the adhesive. The load carrying capacity decreased significantly at temperatures approaching or exceeding Tg. The interfacial fracture energy showed a similar degradation trend. Analytical models of the ultimate bearing capacity, interfacial fracture energy, and bond-slip relationship of CFRP-steel interface at elevated temperatures were presented.

Preliminary studies on steel slag as a substitute for coarse aggregate on concrete

Directory of Open Access Journals (Sweden)

Karolina Rahmi

2017-01-01

Full Text Available The development of science and technology in the field of construction that is rapidly increasing, is always followed by the growing community needs for infrastructure facilities, such as buildings, bridges and other construction. One of the key element in that development is concrete. Due to the rapid development of science and technology in the field of construction, it’s required a building material which has better advantage than the materials of the existing building. To obtain a better building materials, one alternative is the use of waste as aggregate in concrete mixture. In this study the authors using waste steel waste (steel slag as a substitute for coarse aggregate. Steel slag used is steel waste from PT. Growth Sumatra Industry. The gravel substitution variations is 0%, 15%, and 25% and the testing was done by the slump test, compressive strength and flexural strength of concrete. From the test results obtained optimum compressive strength variation occurs in 25% substitution of steel slag gravel amounted to 40.481 MPa, whereas for the optimum bending capacity contained in variations of 25% substitution of steel slag gravel amounted to 19.592 N / mm2. And for optimum slump value obtained on the variation of normal concrete. This shows the workability of the concrete normally higher than the other variation.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

FLEXURAL TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE

Directory of Open Access Journals (Sweden)

Fehmi ÇİVİCİ

2006-02-01

Full Text Available Fiber concrete is a composite material which has mechanical and physical characteristics unlike plain concrete. One of the important mechanical characteristics of fiber concrete is its energy absorbing capability. This characteristics which is also called toughness, is defined as the total area under the load-deflection curve. A number of composite characteristics such as crack resistance, ductility and impact resistance are related to the energy absorbtion capacity. According to ASTM C 1018 and JSCE SF-4 the calculation of toughness is determined by uniaxial flexural testing. Fiber concrete is often used in plates such as bridge decks, airport pavements, parking areas, subjected to cavitation and erosion. In this paper, toughness has been determined according to ASTM C 1018 and JSCE SF-4 methods by testing beam specimens. Energy absorbing capacities of plain and steel fiber reinforced concrete has been compared by evaluating the results of two methods. Also plain and steel fiber reinforced plate specimens behaviors subjected to biaxial flexure are compared by the loaddeflection curves of each specimen.

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

Interim Restorative Approach for the Management of Congenitally Missing Permanent Mandibular Incisors: Presentation of Three Cases

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Prashanth Prakash

2011-01-01

Full Text Available Congenital missing of mandibular permanent incisors with retained primary incisors may jeopardize the esthetic appearance and psychological development of children, especially during the years of transition into adolescence. The retained primary teeth are necessary for the maintenance and normal development of alveolar bone, which in turn is essential for future definitive rehabilitation. In such situations, an interim restoration may be provided before any definitive treatment is given to comfort the young patient during this transition period. Interim restorations may include resin-modified additions to the existing teeth as well as more sophisticated restorations such as resin-retained bridge and removable partial dentures. However, this restoration differs for different clinical situations based on various factors such as age and patient compliance, and also consideration has to be given for the growth changes of the child. The aim of this present paper is to discuss the esthetic management of three cases with bilateral agenesis of permanent mandibular incisors and retained primary incisors with composite interim restoration.

High-strength shape memory steels alloyed with nitrogen

International Nuclear Information System (INIS)

Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

1996-01-01

Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

Science.gov (United States)

Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

2013-03-01

Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

3-D analysis of eddy current in permanent magnet of interior permanent magnet motors

International Nuclear Information System (INIS)

Kawase, Yoshihiro; Yamaguchi, Tadashi; Fukanaga, Hiromu; Ito, Shokichi

2002-01-01

Interior permanent magnet motors are widely used in various fields. However, in high-speed operations, it is important to decrease the eddy current loss in the permanent magnet. In order to decrease the eddy current loss, we propose to divide the permanent magnet. In this paper, we clarified the effect of division of permanent magnet on the eddy current loss using the 3-D finite element method. (Author)

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch required by the Bridge-to-Bridge Act. 80... Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch requirement contained in § 80.148, all vessels subject to the Bridge-to-Bridge Act must keep a watch on the designated...

Comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement

International Nuclear Information System (INIS)

Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Gorican, Viktor; Jesenik, Marko; Trlep, Mladen

2007-01-01

The paper presents a comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement. Motors with the following permanent magnet topologies were accounted for in the comparison: the surface-mounted permanent magnet synchronous motor (SMPMSM), the interior permanent magnet synchronous motor (IPMSM), the permanent magnet-assisted synchronous reluctance motor (PMASRM) and the flux reversal permanent magnet motor (FRPMM). Finite element method analysis is employed to determine the performance of each motor. Calculated performance of four-pole IPMSM determined by finite element method calculation is confirmed with the measurements at nearly constant nominal output power in the range of speed 3000-10,000 rpm

Rheological Characterization of Warm-Modified Asphalt Mastics Containing Electric Arc Furnace Steel Slags

Directory of Open Access Journals (Sweden)

M. Pasetto

2016-01-01

Full Text Available The environmental sustainability of road materials and technologies plays a key role in pavement engineering. In this sense, the use of Warm Mix Asphalt (WMA, that is, a modified asphalt concrete that can be produced and applied at lower temperature, is considered an effective solution leading to environmental and operational benefits. The environmental sustainability of WMA can be further enhanced with the inclusion of steel slag in partial substitution of natural aggregates. Nevertheless, such innovative material applied at lower temperatures containing warm additives and steel slag should be able to guarantee at least the same performance of traditional hot mix asphalts, thus assuring acceptable mechanical properties and durability. Therefore, the purpose of this study is to investigate the rheological behaviour of bituminous mastics obtained combining a warm-modified binder and a filler (material passing to 0.063 mm coming from electric arc furnace steel slag. To evaluate the influence of both warm additive and steel slag, a plain binder and limestone filler were also used for comparison purposes. Complex modulus and permanent deformation resistance of bitumens and mastics were assessed using a dynamic shear rheometer. Experimental results showed that steel slag warm mastics assure enhanced performance demonstrating promising applicability.

Field performance of timber bridges. 7, Connell Lake stress-laminated deck bridge

Science.gov (United States)

L. E. Hislop; M. A. Ritter

The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored...

Permanent quadrupole magnets

International Nuclear Information System (INIS)

Bush, E.D. Jr.

1976-01-01

A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime

Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

Directory of Open Access Journals (Sweden)

Rong Chen

2013-01-01

Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

Energy Technology Data Exchange (ETDEWEB)

Liang, Peixin; Chai, Feng [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bi, Yunlong [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Pei, Yulong, E-mail: peiyulong1@163.com [Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cheng, Shukang [State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001 (China); Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2016-11-01

Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.

Analytical model and design of spoke-type permanent-magnet machines accounting for saturation and nonlinearity of magnetic bridges

International Nuclear Information System (INIS)

Liang, Peixin; Chai, Feng; Bi, Yunlong; Pei, Yulong; Cheng, Shukang

2016-01-01

Based on subdomain model, this paper presents an analytical method for predicting the no-load magnetic field distribution, back-EMF and torque in general spoke-type motors with magnetic bridges. Taking into account the saturation and nonlinearity of magnetic material, the magnetic bridges are equivalent to fan-shaped saturation regions. For getting standard boundary conditions, a lumped parameter magnetic circuit model and iterative method are employed to calculate the permeability. The final field domain is divided into five types of simple subdomains. Based on the method of separation of variables, the analytical expression of each subdomain is derived. The analytical results of the magnetic field distribution, Back-EMF and torque are verified by finite element method, which confirms the validity of the proposed model for facilitating the motor design and optimization. - Highlights: • The no-load magnetic field of poke-type motors is firstly calculated by analytical method. • The magnetic circuit model and iterative method are employed to calculate the permeability. • The analytical expression of each subdomain is derived.. • The proposed method can effectively reduce the predesign stages duration.

Study of technology of pile foundation construction of no.5 main pier of Shoujiang bridge in Wenchuan County

Science.gov (United States)

Huang, Xianbin; Liu, Chenyang; Chen, Chunyang; Wangren, Yahong; Xu, Jialin; Xian, Jin

2018-03-01

The group of pile foundation of no.5 pier in Shoujiang Bridge needs to overcome the big load of large span continuous steel structure. The length of single pile foundation is 77m and the diameter of single pile foundation is 250cm. It not only faces the flood in the upstream of Shoujiang river, the construction obstacles during summer rain period, but also the reservoir clearance activity of Zipingpu reservoir and the high water level in winter and other water level fluctuation that have huge impact on platform of pile foundation construction. This article introduces the preparation in aspect of personnel, material, equipment and so on of pile foundation construction, and also conduct intensive research on leveling the field, assaying pile location, the embedment of the steel casing, installing the drill, mixing mud, drilling, final hole inspection and clearance, steel cage construction, perfusing concrete under water.

Comparative testing of radiographic testing, ultrasonic testing and phased array advanced ultrasonic testing non destructive testing techniques in accordance with the AWS D1.5 bridge welding code.

Science.gov (United States)

2014-02-01

A comprehensive body of non-destructive testing data was collected from steel bridge welds under real-world conditions in a fabricators shop. Three different non-destructive testing (NDT) techniques were used on each weld inspection, these being R...

Microstructural features of dissimilar welds between 316LN austenitic stainless steel and alloy 800

International Nuclear Information System (INIS)

Sireesha, M.; Sundaresan, S.

2000-01-01

For joining type 316LN austenitic stainless steel to modified 9Cr-1Mo steel for power plant application, a trimetallic configuration using an insert piece (such as alloy 800) of intermediate thermal coefficient of expansion (CTE) has been sometimes suggested for bridging the wide gap in CTE between the two steels. Two joints are thus involved and this paper is concerned with the weld between 316LN and alloy 800. These welds were produced using three types of filler materials: austenitic stainless steels corresponding to 316,16Cr-8Ni-2Mo, and the nickel-base Inconel 182 1 . The weld fusion zones and the interfaces with the base materials were characterised in detail using light and transmission electron microscopy. The 316 and Inconel 182 weld metals solidified dendritically, while the 16-8-2(16%Cr-8%Ni-2%Mo) weld metal showed a predominantly cellular substructure. The Inconel weld metal contained a large number of inclusions when deposited from flux-coated electrodes, but was relatively inclusion-free under inert gas-shielded welding. Long-term elevated-temperature aging of the weld metals resulted in embrittling sigma phase precipitation in the austenitic stainless steel weld metals, but the nickel-base welds showed no visible precipitation, demonstrating their superior metallurgical stability for high-temperature service. (orig.)

Performance of an Adjustable Strength Permanent Magnet Quadrupole

CERN Document Server

Gottschalk, Stephen C; Kangas, Kenneth; Spencer, Cherrill M; Volk, James T

2005-01-01

An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic centerline and field quality made using an air bearing rotating coil system. The magnetic centerline stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic centerline. Calibration procedures as well as centerline measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.

Ultrasonic assessment of service life of concrete structures subject to reinforcing steel corrosion

Science.gov (United States)

Udegbunam, Ogechukwu Christian

Over half of the bridges in the United States were built before 1970. Such bridges and the network of roads that they carry include the Inter State system, which was built as part of the great public works program, following the end of the Second World War. During that era, the emphasis was on strength design and economical construction of new structures, and not much premium was placed on durability and maintainability concerns. Since the end of this construction boom in the early 1970s, the concern for the durability of transportation infrastructure has steadily gained prominence among those agencies that must secure, program and administer funds for maintaining highway networks. The objective of this research was to develop a nondestructive method of assessing the durability of concrete bridge decks susceptible to damage from corrosion of embedded reinforcing steel. This was accomplished by formulating a holistic approach that accounts for the major factors that influence corrosion based deterioration of reinforced concrete. In this approach, the assessment of the durability of concrete bridge decks is based on a model that estimates the time it takes for the cover concrete to fail a result of stresses caused by expansion of reinforcing steel bars, due to corrosion activities. This time to failure is comprised of two distinct periods that must be evaluated before the problem can be solved. The research consisted of an experimental program and an analytical study. In the experimental program concrete specimens were cast and tested to determine their diffusivity and mechanical properties. The diffusivity was used to evaluate the period it takes for corrosion of the reinforcing bars to commence. In the analytical study, the resistance of the concrete structure against the internal forces caused by corrosion was evaluated with the finite element techniques. This resistance was used to evaluate the period defining the failure of the cover concrete. These two periods

Strengthening of RC bridge slabs using CFRP sheets

Directory of Open Access Journals (Sweden)

Fahmy A. Fathelbab

2014-12-01

Full Text Available Many old structures became structurally insufficient to carry the new loading conditions requirements. Moreover, they suffer from structural degradation, reinforcement steel bars corrosion, bad weather conditions…etc. Many official authorities in several countries had recognized many old bridges and buildings as structurally deficient by today’s standards. Due to these reasons, structural strengthening became an essential requirement and different strengthening techniques appeared in market. Fiber Reinforced Polymer (FRP strengthening techniques established a good position among all other techniques, giving excellent structural results, low time required and moderate cost compared with the other techniques. The main purpose of this research is to study analytically the strengthening of a reinforced concrete bridge slabs due to excessive loads, using externally bonded FRP sheets technique. A commercial finite element program ANSYS was used to perform a structural linear and non-linear analysis for strengthened slab models using several schemes of FRP sheets. A parametric study was performed to evaluate analytically the effect of changing both FRP stiffness and FRP schemes in strengthening RC slabs. Comparing the results with control slab (reinforced concrete slab without strengthening it is obvious that attaching FRP sheets to the RC slab increases its capacity and enhances the ductility/toughness.

Bridges

NARCIS (Netherlands)

Zant, W.

2017-01-01

We estimate to what extent bridges in Mozambique lead to transport cost reductions and attribute these reductions to key determinants, in particular road distance, road quality and crossing borders. For identification we exploit the introduction of a road bridge over the Zambezi river, in August

Design and construction of Chichibu-park bridge. Chichibu Koenkyo (kasho) no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Hasuike, H.; Azami, Y. (Saitama Prefectural Government Office, Saitama (Japan) New Structural Engineering, Ltd., Tokyo (Japan)); Yamamoto, T.

1994-01-31

The design and construction of the Chichibu-Park Bridge in Japan were outlined which is the symmetric 2-span continuous PC cable stayed road bridge with one main tower (530 m in total length, 392 m in main bridge length, 19 m in width) built over the Arakawa River. The double-suspended four-box main girder with wind noses was adopted because of its excellent torsional rigidity of area and wind proof stability, and the rigid-frame main girder was rigidly connected to the middle main tower. The main tower with an H-type hollow section was adopted considering its workability, and was assembled with its divided 18 blocks. Each side of the main girder was suspended at 30 points spaced at 6.0 m, and the tower ends of the diagonal cables were fixed to the partition inside the main tower taking a landscape into account. The thick stranded wires composed of fine PC steel stranded wires and covered with polyethylene were adopted as diagonal cables, and structural beams were used for both ends of the diagonal cables. Damping wires were also adopted to damp the diagonal cables. 9 refs., 12 figs., 6 tabs.

Using a very low level radioactive steel from decommissioning of nuclear installation for the construction of railway structures

International Nuclear Information System (INIS)

Slimak, A.; Necas, V.

2012-01-01

During the operation, but especially during decommissioning (SW) of operation, there is a large amount of radioactive waste, whose activity only slightly exceeds the limits for unrestricted use, or for the unconditional release into the environment. In particular, metal and concrete debris. Processing, treatment and disposal of such waste would require considerable funds, and also storage space would be quickly filled up. A convenient way to use a large number of low-activity materials seems to be conditional release, which will reuse the materials for a particular purpose. The paper deals with use of a very low level of steel from decommissioning of nuclear installations for construction of the railway bridge. The task of the present paper is to review the impact of conditionally released steel on population and to determine what level of mass activity of the steel meets the limits prescribed by law. For impact assessment of conditionally released steel on population there was selected computing resource VISIPLAN 3D ALARA Planning Tool. (author)

New types of time domain reflectometry sensing waveguides for bridge scour monitoring

Science.gov (United States)

Lin, Chih-Ping; Wang, Kai; Chung, Chih-Chung; Weng, Yu-Wen

2017-07-01

Scour is a major threat to bridge safety, especially in harsh fluvial environments. Real-time monitoring of bridge scour is still very limited due to the lack of robust and economic scour monitoring device. Time domain reflectometry (TDR) is an emerging waveguide-based technique holding great promise to develop more durable scour monitoring devices. This study presents new types of TDR sensing waveguides in forms of either sensing rod or sensing wire, taking into account of the measurement range, durability, and ease of field installation. The sensing rod is composed of a hollow grooved steel rod paired up with a metal strip on the insulating groove, while the sensing wire consists of two steel strands with one of them coated with an insulating jacket. The measurement sensitivity is inevitably sacrificed when other properties such as the measurement range, field durability, and installation easiness are enhanced. Factors affecting the measurement sensitivity were identified and experimentally evaluated for better arranging the waveguide conductors. A data reduction method for scour-depth estimation without the need for identifying the sediment/water reflection and a two-step calibration procedure for rating propagation velocities were proposed to work with the new types of TDR sensing waveguides. Both the calibration procedure and the data reduction method were experimentally validated. The test results indicated that the new TDR sensing waveguide provides accurate scour depth measurements regardless of the sacrificed sensitivity. The insulating coating of the new TDR sensing waveguide was also demonstrated to be effective in extending the measurement range up to at least 15 m.

Field performance of timber bridges. 4, Graves Crossing stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter

The Graves Crossing bridge was constructed October 1991 in Antrim County, Michigan, as part of the demonstration timber bridge program sponsored by the USDA Forest Service. The bridge is a two-span continuous, stress-laminated deck superstructure and it is 36-ft long and 26-ft wide. The bridge is one of the first stress-laminated deck bridges to be built of sawn lumber...

Clearance of radioactive materials during reactor dismantling. Permanent enclosure instead of demolition and renaturation?

International Nuclear Information System (INIS)

2016-01-01

During reactor dismantling besides high-level radioactive wastes a large amount of low-level contaminated steel and concrete has to be disposed. In case that radioactivity falls below defined dose limits (10 micro Sv/person and year) these materials may be disposed in domestic waste landfill or in municipal incineration facilities. The issue is discussed in detail including the fact that many power plants are dismantled at the same time so that the contaminated materials might accumulate. Another issue is the occupational safety of contract workers during dismantling. The permanent enclosure could avoid this environmental contamination of decommissioned power plants might also be less expensive.

Myocardial Bridging

Directory of Open Access Journals (Sweden)

Shi-Min Yuan

2016-02-01

Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

The hepatic bridge.

Science.gov (United States)

Sugarbaker, Paul H

2018-07-01

The hepatic bridge forms a tunnel of liver parenchyma that may obscure peritoneal metastases associated with the round ligament. Visualization and then resection of nodules associated with this structure is necessary. The incidence of a hepatic bridge and the extent that it covered the round ligament was determined in consecutive patients. Extent of coverage of the round ligament by the hepatic bridge was determined: Class 1 indicates up to one-third of the round ligament obscured, Class 2 up to two-thirds and Class 3 more than two-thirds. In 102 patients in whom the round ligament of the liver could be completely visualized, 50 had a hepatic bridge. Class 1 was 22 (44%) of the bridges, Class 2 was 16 (32%) and Class 3 was 12 (24%). A hepatic bridge was more frequently present in 28 of 45 male patients (62%) vs. 22 of 57 female patients (38%). Approximately one-half of our patients having cytoreductive surgery for peritoneal metastases were observed to have a hepatic bridge. Up to 56% of these patients have Class 2 or 3 hepatic bridge and may require division of the hepatic bridge to completely visualize the contents of the tunnel created by this structure. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Damage Assessment of Heat Resistant Steels through Electron BackScatter Diffraction Strain Analysis under Creep and Creep-Fatigue Conditions

Science.gov (United States)

Fujiyama, Kazunari; Kimachi, Hirohisa; Tsuboi, Toshiki; Hagiwara, Hiroyuki; Ogino, Shotaro; Mizutani, Yoshiki

EBSD(Electron BackScatter Diffraction) analyses were conducted for studying the quantitative microstructural metrics of creep and creep-fatigue damage for austenitic SUS304HTB boiler tube steel and ferritic Mod.9Cr piping steel. KAM(Kernel Average Misorientation) maps and GOS(Grain Orientation Spread) maps were obtained for these samples and the area averaged values KAMave and GOSave were obtained. While the increasing trends of these misorientation metrics were observed for SUS304HTB steel, the decreasing trends were observed for damaged Mod.9Cr steel with extensive recovery of subgrain structure. To establish more universal parameter representing the accumulation of damage to compensate these opposite trends, the EBSD strain parameters were introduced for converting the misorientation changes into the quantities representing accumulated permanent strains during creep and creep-fatigue damage process. As KAM values were dependent on the pixel size (inversely proportional to the observation magnification) and the permanent strain could be expressed as the shear strain which was the product of dislocation density, Burgers vector and dislocation movement distance, two KAM strain parameters MεKAMnet and MεδKAMave were introduced as the sum of product of the noise subtracted KAMnet and the absolute change from initial value δKAMave with dislocation movement distance divided by pixel size. MεδKAMave parameter showed better relationship both with creep strain in creep tests and accumulated creep strain range in creep-fatigue tests. This parameter can be used as the strain-based damage evaluation and detector of final failure.

Case study: highly loaded MSE bridge supporting structure, Syncrude NMAPS conveyor overpasses

Energy Technology Data Exchange (ETDEWEB)

Scherger, B.; Brockbank, B. [Reinforced Earth Company Ltd., Edmonton, AB (Canada); Mimura, W. [Syncrude Canada Ltd., Edmonton, AB (Canada)

2005-07-01

A crusher and conveyor system was constructed at the Mildred Lake Oil Sands Mine near Fort McMurray, Alberta in order to facilitate ore delivery from Syncrude's North Mine. As part of this North Mine Auxiliary Production System (NMAPS), Syncrude Canada and their consultant Cosyn Technology identified the need for 3 overpasses over conveyors in the North Mine in order to provide unrestricted crossing over the operating conveyor system for the heavy hauler trucks and light vehicle mine traffic. The overpasses were designed to support the dead load of the granular fill and the live load of two loaded heavy hauler trucks, with a design load for each loaded hauler of 670 900 kg. This paper reviewed various aspects of the design from planning, structure selection, and overall stability and bearing capacity considerations. The different designs in the 3 new overpasses accommodated foundation and loading requirements. The designs ranged from the use of precast one-piece reinforced concrete arches, Mechanically Stabilized Earth (MSE) bridge abutment technology, and a combination of the two. The MSE retaining walls directly supported the bridge superstructure without the use of piles or other deep structural foundations. The design was challenging because of the significant vertical stresses transferred onto the wall. All 3 overpasses also used MSE walls for the supporting end wing walls. The main focus of this paper was on the heavily loaded MSE walls supporting the bridge abutment style overpasses. This structure has illustrated the capability of properly designed MSE wall structures with steel soil reinforcement and reinforced precast concrete face panels to successfully carry bridge footing pressure loadings up to 545 kPa. It was concluded that this case has good potential for use in future bridge projects in both the industrial and highway sectors. 2 refs., 7 figs.

Bridge resource program.

Science.gov (United States)

2013-09-01

The mission of Rutgers Universitys Center for Advanced Infrastructure and Transportation (CAIT) Bridge Resource Program (BRP) is to provide bridge engineering support to the New Jersey Department of Transportation (NJDOT)s Bridge Engineering an...

Composite material pedestrian bridge for the Port of Bilbao

Science.gov (United States)

Gorrochategui, I.; Manteca, C.; Yedra, A.; Miguel, R.; del Valle, F. J.

2012-09-01

Composite materials in comparison to traditional ones, steel and concrete, present advantages in civil works construction: lower weight, higher corrosion resistance (especially in the marine environment), and ease of installation. On the other hand, fabrication costs are generally higher. This is the reason why this technology is not widely used. This work illustrates the process followed for the design, fabrication and installation of a composite material pedestrian bridge in the Port of Bilbao (Northern Spain). In order to reduce the price of the bridge, the use of low cost materials was considered, therefore polyester resin was selected as the polymeric matrix, and glass fibres as reinforcement. Two material choices were studied. Currently in the market there is high availability of carbon nanoparticles: carbon nanotubes (CNT) and carbon nanofibres (CNF), so it was decided to add this kind of nanoparticles to the reference material with the objective of improving its mechanical properties. The main challenge was to transfer the CNT and CNF excellent properties to the polymeric matrix. This requires dispersing the nanoreinforcements as individual particles in the polymeric matrix to avoid agglomerates. For this reason, an advanced high shear forces dispersion technique (called "three roll mills") was studied and implemented. Also surface functionalization of the nanoreinforcements by chemical treatment was carried out. Herein, a comparison is performed between both materials studied, the explanation of the employment of the reference material (without nanoreinforcement) as the one used in the fabrication of the pedestrian bridge is justified and, finally, the main characteristics of the final design of the structural element are described.

Composite material pedestrian bridge for the Port of Bilbao

International Nuclear Information System (INIS)

Gorrochategui, I; Manteca, C; Yedra, A; Miguel, R; Valle, F J del

2012-01-01

Composite materials in comparison to traditional ones, steel and concrete, present advantages in civil works construction: lower weight, higher corrosion resistance (especially in the marine environment), and ease of installation. On the other hand, fabrication costs are generally higher. This is the reason why this technology is not widely used. This work illustrates the process followed for the design, fabrication and installation of a composite material pedestrian bridge in the Port of Bilbao (Northern Spain). In order to reduce the price of the bridge, the use of low cost materials was considered, therefore polyester resin was selected as the polymeric matrix, and glass fibres as reinforcement. Two material choices were studied. Currently in the market there is high availability of carbon nanoparticles: carbon nanotubes (CNT) and carbon nanofibres (CNF), so it was decided to add this kind of nanoparticles to the reference material with the objective of improving its mechanical properties. The main challenge was to transfer the CNT and CNF excellent properties to the polymeric matrix. This requires dispersing the nanoreinforcements as individual particles in the polymeric matrix to avoid agglomerates. For this reason, an advanced high shear forces dispersion technique (called 'three roll mills') was studied and implemented. Also surface functionalization of the nanoreinforcements by chemical treatment was carried out. Herein, a comparison is performed between both materials studied, the explanation of the employment of the reference material (without nanoreinforcement) as the one used in the fabrication of the pedestrian bridge is justified and, finally, the main characteristics of the final design of the structural element are described.

Bridged graphite oxide materials

Science.gov (United States)

Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

2010-01-01

Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

Laboratory and field testing of an accelerated bridge construction demonstration bridge : US Highway 6 bridge over Keg Creek.

Science.gov (United States)

2013-04-01

The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice : newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated ...

Constitutive modelling of stainless steels for cryogenic applications. Strain induced martensitic transformation

CERN Document Server

Garion, C

2001-01-01

The 300-series stainless steels are metastable austenitic alloys: martensitic transformation occurs at low temperatures and/or when plastic strain fields develop in the structures. The transformation influences the mechanical properties of the material. The present note aims at proposing a set of constitutive equations describing the plastic strain induced martensitic transformation in the stainless steels at cryogenic temperatures. The constitutive modelling shall create a bridge between the material sciences and the structural analysis. For the structures developing and accumulating plastic deformations at sub-zero temperatures, it is of primary importance to be able to predict the intensity of martensitic transformation and its effect on the material properties. In particular, the constitutive model has been applied to predict the behaviour of the components of the LHC interconnections, the so-called bellows expansion joints (the LHC mechanical compensation system).

A Review on Strengthening Steel Beams Using FRP under Fatigue

Directory of Open Access Journals (Sweden)

Mohamed Kamruzzaman

2014-01-01

Full Text Available In recent decades, the application of fibre-reinforced polymer (FRP composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems.

A review on strengthening steel beams using FRP under fatigue.

Science.gov (United States)

Kamruzzaman, Mohamed; Jumaat, Mohd Zamin; Sulong, N H Ramli; Islam, A B M Saiful

2014-01-01

In recent decades, the application of fibre-reinforced polymer (FRP) composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE) simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP) is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems.

A Review on Strengthening Steel Beams Using FRP under Fatigue

Science.gov (United States)

Jumaat, Mohd Zamin; Ramli Sulong, N. H.

2014-01-01

In recent decades, the application of fibre-reinforced polymer (FRP) composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE) simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP) is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems. PMID:25243221

Guardrails for Use on Historic Bridges: Volume 2—Bridge Deck Overhang Design

OpenAIRE

Frosch, Robert J.; Morel, Adam J.

2016-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

Design and fabrication of radial flux permanent magnet generator for wind turbine applications

International Nuclear Information System (INIS)

Ashraf, M.M.; Malik, T.N.; Zafar, S.; Raja, U.N.

2013-01-01

Presently alternate energy resources are replacing conventional energy sources to produce electrical power to minimize the usage of fossil fuels. Wind power is one of the potential alternate energy resources and is being exploited and deployed actively. The wind energy system is basically composed of two core components: wind turbine and electrical generator. This paper presents the design and fabrication of permanent magnet generator for direct drive wind turbine applications. Radial flux permanent magnet generator (RFPMG) producing three phase alternating current voltage has been designed subject to satisfying the features of low operating shaft speed, higher power density , higher current density, cost effectiveness and compact structure. RFPMG design focuses on usage of neodymium permanent magnets for excitation instead of electromagnets to minimize the excitation arrangement challenges and losses. A 300 W prototype RFPMG has been fabricated. The performance of the generator has been evaluated on specially designed wind tunnel. The generator is directly coupled with wind turbine shaft to eliminate the gearbox losses. No load and load tests show that the performance of the machine is up to the mark. The improved design parameters of power density and current density are 73.2 W/kg and 5.9 A/mm 2 respectively. The same machine output has been rectified using bridge rectifier for battery charging application. The desired output voltages are obtained at minimum shaft speed of the generator. Thus the design of generator confirms its application with small scale domestic wind turbines produci ng direct current supply. (author)

Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

Directory of Open Access Journals (Sweden)

Gao-Xin Wang

2015-01-01

Full Text Available Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference and train. After the train-induced static strains are removed, the correlation between the remaining static strains and the temperature field shows apparent linear characteristics, which can be mathematically modeled for the description of static performance. Therefore, multivariate linear regression function combined with principal component analysis is introduced to mathematically model the correlation. Furthermore, the residual static strains of mathematical model are adopted as assessment indicator and three kinds of degradation regulations of static performance are obtained after simulation of the residual static strains. Finally, it is concluded that the static performance of Dashengguan Yangtze Bridge was in a good condition during that period.

Skewed steel bridges, part ii : cross-frame and connection design to ensure brace effectiveness : technical summary.

Science.gov (United States)

2017-08-01

Skewed bridges in Kansas are often designed such that the cross-frames are carried parallel to the skew angle up to 40, while many other states place cross-frames perpendicular to the girder for skew angles greater than 20. Skewed-parallel cross-...

Skewed steel bridges, part ii : cross-frame and connection design to ensure brace effectiveness : final report.

Science.gov (United States)

2017-08-01

Skewed bridges in Kansas are often designed such that the cross-frames are carried parallel to the skew angle up to 40, while many other states place cross-frames perpendicular to the girder for skew angles greater than 20. Skewed-parallel cross-...

Full Pulpotomy with Biodentine in Symptomatic Young Permanent Teeth with Carious Exposure.

Science.gov (United States)

Taha, Nessrin A; Abdulkhader, Sakhaa Z

2018-04-19

This prospective study evaluated the outcome of Biodentine (Septodont, Saint Maur des Fosses, France) pulpotomy in young permanent teeth with carious exposure. Twenty permanent molar teeth in 14 patients with carious pulp exposure were treated with Biodentine pulpotomy. The age of the patients ranged from 9-17 years (12.3 ± 2.7 years). A preoperative pulpal and periapical diagnosis was established. After informed consent, the tooth was anesthetized, isolated via a dental dam, and disinfected with 5% sodium hypochlorite before caries excavation. Full pulpotomy was performed by amputating the exposed pulp to the level of the canal orifices, hemostasis was achieved via a cotton pellet moistened with 2.5% sodium hypochlorite, a 3-mm layer of Biodentine was placed as the pulpotomy agent, a Vitrebond liner (3M ESPE, St Paul, MN) was applied, and the tooth was subsequently restored. Postoperative periapical radiographs were taken after placement of the permanent restoration. Clinical and radiographic evaluation was completed after 6 months and 1 year postoperatively. Pain levels were scored preoperatively and 2 days after treatment. Statistical analysis was performed using the Fisher exact test. Clinical signs and symptoms suggestive of irreversible pulpitis were established in all teeth and symptomatic apical periodontitis in 14 of 20 (70%). Two days after treatment, all patients reported complete relief of pain. All teeth were clinically successful at 6 months and 1 year postoperatively. Radiographically, immature roots showed continued root development; dentin bridge formation was detected in 5 of 20 teeth. Seven of 7 teeth with preoperative periapical rarefaction showed signs of healing; 1 tooth had signs of internal root resorption at 1 year with an overall success rate of 95% (19/20). Young permanent teeth with carious exposure can be treated successfully with full pulpotomy using Biodentine, and clinical signs and symptoms of irreversible pulpitis are

Design and construction of PC cable-stayed bridge reducing the weight of dead load (Minamitabaru No. 1 Bridge). Shuko danmen no keiryoka wo hakatta PC shachokyo (kasho Minamitabaru 1 go kyo)

Energy Technology Data Exchange (ETDEWEB)

Otsuka, H. (Building Research Inst., Tokyo (Japan)); Ikari, K.; Ono, Y. (Ministry of Construction, Tokyo (Japan)); Hirano, A.

1993-03-15

The Minamitabaru No.1 bridge is a PC cable-stayed bridge with a 170m center span. The cross section dead load weight of the main beam in the center span is reduced to decrease the unbalance moment during construction and the negative reaction force after the completion. As a result, the average volume of concrete in the center span becomes 0.55m[sup 3]/m[sup 2] which is less by about 20% in comparison with a PC cable-stayed bridge of the similar scale. Separated 2 chamber box girder cross section is adopted for the shape of the main beam cross section to reduce the dead load weight of the cross section, and to improve the rigidity of the cross section and wind resisting stability, etc. In addition, a cross beam is provided in the diagonal member anchorage position to integrate the two box beams. A wind tunnel test is performed using a 1/30 scale model to confirm the wind resisting stability. The diagonal member is structured with several PC steel members. At the same time, a stretching work carriage is developed and used which can establish 3 dimensional position and direction by a hydraulic jack. 7 figs.

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction

Science.gov (United States)

2017-09-01

Concrete bridge decks are directly exposed to daily traffic loads and may experience some surface cracking caused by excessive stress or fatigue accumulation, which requires repair or replacement. Among typical bridges in North America, bridge decks ...

Permanent magnets including undulators and wigglers

CERN Document Server

Bahrdt, J

2010-01-01

After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrates on the applications of permanent magnets in accelerators starting from dipoles and quadrupoles on to wigglers and undulators.

Prevalence of permanent hearing threshold shift among workers of Indian iron and steel small and medium enterprises: a study.

Science.gov (United States)

Singh, Lakhwinder Pal; Bhardwaj, Arvind; Kumar, Deepak Kishore

2012-01-01

Occupational noise exposure and noise-induced hearing loss (NIHL) have been recognized as a problem among workers in Indian industries. The major industries in India are based on manufacturing. There are appreciable numbers of casting and forging units spread across the country. The objective of this study is to determine the prevalence of permanent hearing threshold shift among the workers engaged in Indian iron and steel small and medium enterprises (SMEs) and compared with control group subjects. As a part of hearing protection intervention, audiometric tests were conducted at low (250-1000 Hz), medium (1500-3000 Hz), and high (4000-8000 Hz) frequencies. The occurrence of hearing loss was determined based on hearing threshold levels with a low fence of 25 dB. Comparisons were made for hearing threshold at different frequencies between the exposed and control groups using Student's t test. ANOVA was used for the comparison of hearing threshold dB at different frequencies among occupation and year of experience. A P value workers engaged in various processes of casting and forging industry showed hearing loss in the noise-sensitive medium and higher frequencies. Occupation was significantly associated with NIHL, and hearing loss was particularly high among the workers of forging section. The analyses revealed a higher prevalence of significant hearing loss among the forging workers compared to the workers associated with other activities. The study shows alarming signals of NIHL, especially in forging workers. The occupational exposure to noise could be minimized by efficient control measures through engineering controls, administrative controls, and the use of personal protective devices. Applications of engineering and/or administrative controls are frequently not feasible in the developing countries for technical and financial reasons. A complete hearing conservation programme, including training, audiometry, job rotation, and the use of hearing protection

Prevalence of permanent hearing threshold shift among workers of Indian iron and steel small and medium enterprises: A study

Directory of Open Access Journals (Sweden)

Lakhwinder Pal Singh

2012-01-01

Full Text Available Occupational noise exposure and noise-induced hearing loss (NIHL have been recognized as a problem among workers in Indian industries. The major industries in India are based on manufacturing. There are appreciable numbers of casting and forging units spread across the country. The objective of this study is to determine the prevalence of permanent hearing threshold shift among the workers engaged in Indian iron and steel small and medium enterprises (SMEs and compared with control group subjects. As a part of hearing protection intervention, audiometric tests were conducted at low (250-1000 Hz, medium (1500-3000 Hz, and high (4000-8000 Hz frequencies. The occurrence of hearing loss was determined based on hearing threshold levels with a low fence of 25 dB. Comparisons were made for hearing threshold at different frequencies between the exposed and control groups using Student′s t test. ANOVA was used for the comparison of hearing threshold dB at different frequencies among occupation and year of experience. A P value <0.05 was considered as statistically significant. All data were presented as mean value (SD. Over 90% of workers engaged in various processes of casting and forging industry showed hearing loss in the noise-sensitive medium and higher frequencies. Occupation was significantly associated with NIHL, and hearing loss was particularly high among the workers of forging section. The analyses revealed a higher prevalence of significant hearing loss among the forging workers compared to the workers associated with other activities. The study shows alarming signals of NIHL, especially in forging workers. The occupational exposure to noise could be minimized by efficient control measures through engineering controls, administrative controls, and the use of personal protective devices. Applications of engineering and/or administrative controls are frequently not feasible in the developing countries for technical and financial reasons. A

Evaluation of seismic damage to bridges and highway systems in Shelby County, Tennessee

Science.gov (United States)

Jernigan, John Bailey

by the Capacity/Demand (C/D) ratios of bridge components. The damage states considered in this study are no/minor damage, repairable damage, and significant damage. The seismic fragility analysis of each bridge classification was performed and the results were expressed as fragility curves. In this study, eight bridge classifications were defined and a fragility curve was developed for each. To estimate the seismic hazard, three scenario earthquakes located at Marked Tree, Arkansas was established for this study. The moment magnitude of the M scenario earthquake was set as 6.5, 7.0, and 7.5 to represent various sizes of earthquakes that might occur in the NMSZ. For each scenario earthquake, the intensity of ground shaking and liquefaction-induced permanent ground deformation in Shelby County were estimated, and then the expected damage to bridges and roadway systems was determined. The results from this study can be used to prioritize bridges for retrofitting, to prepare a pre-earthquake preparedness plan, and to develop a post-earthquake emergency response plan. Furthermore, the results can also be used to assess the regional economic impact from the damage to highway transportation systems.

Estimation of nonlinearities from pseudodynamic and dynamic responses of bridge structures using the Delay Vector Variance method

Science.gov (United States)

Jaksic, Vesna; Mandic, Danilo P.; Karoumi, Raid; Basu, Bidroha; Pakrashi, Vikram

2016-01-01

Analysis of the variability in the responses of large structural systems and quantification of their linearity or nonlinearity as a potential non-invasive means of structural system assessment from output-only condition remains a challenging problem. In this study, the Delay Vector Variance (DVV) method is used for full scale testing of both pseudo-dynamic and dynamic responses of two bridges, in order to study the degree of nonlinearity of their measured response signals. The DVV detects the presence of determinism and nonlinearity in a time series and is based upon the examination of local predictability of a signal. The pseudo-dynamic data is obtained from a concrete bridge during repair while the dynamic data is obtained from a steel railway bridge traversed by a train. We show that DVV is promising as a marker in establishing the degree to which a change in the signal nonlinearity reflects the change in the real behaviour of a structure. It is also useful in establishing the sensitivity of instruments or sensors deployed to monitor such changes.

Cable Supported Bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

Marxism as permanent revolution

NARCIS (Netherlands)

van Ree, E.

2013-01-01

This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not

Cassette pontoon bridge of high mobility

Directory of Open Access Journals (Sweden)

Krzysztof KOSIUCZENKO

2011-01-01

Full Text Available Looking through the known and used buoyant systems, it can be remarked that the single buoyant segments are the stiff objects made of steel or plastic with variable dimensions and a complex construction. The ready to use buoyant segments, that assure the proper displacement, must have the factory leak-tightness. They take up a big transportation volume and need the assurance of the suitably abundant means of transport. Usually the heavy wheeled vehicles are needed because of high own mass of buoyant segment and large gauges. The exploitation of such constructions is very expensive. A cassette pontoon bridge, presented in this paper, is the proposition of the increase of the mobility of construction. The decrease of the single buoyant segment dimensions with the assurance of the capacity leads that more segments fit into in the same dimensions of the loading compartment of the vehicle and storage accommodation. The application of standardized joints assures the assembly efficiency with not numerous crew.

Bridge Programs in Illinois: Results of the 2010 Illinois Bridge Status Survey

Science.gov (United States)

Taylor, J. L.; Harmon, T.

2010-01-01

This report provides a summary of major results of the Illinois Bridge Status Survey, administered online between April and June 2010. The purpose of the survey was to understand the extent to which bridge programs are being implemented in Illinois, as well as to build an online directory of bridge programs. Bridge programs are an emerging…

Field performance of timber bridges. 6, Hoffman Run stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; P. D. Hilbrich Lee; G. J. Porter

The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was...

Experimental investigation of asphalt mixture containing Linz-Donawitz steel slag

Directory of Open Access Journals (Sweden)

Jens Groenniger

2017-08-01

Full Text Available Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton with industrial by-products such as slag originating from steel production process. However, little is known on the effect of steel slag on the mixtures performance properties such as resistance to low-temperature cracking and to permanent deformation, stiffness and fatigue. This paper presents a comprehensive investigation on the fundamental performance properties of different types of asphalt mixtures prepared with 100% LD slag aggregate and a conventional asphalt mixture containing natural Gabbro aggregate. Sophisticated testing methods were used to evaluate the key performance parameters for the set of asphalt mixtures investigated. In this study, low temperature cracking was addressed through thermal stress restrained specimen tests. Penetration tests and cyclic compression tests were used to evaluate the response of asphalt binder and asphalt mixture to permanent deformation due repeated loading, respectively. The cyclic indirect tensile test was selected for investigating both stiffness properties and fatigue resistance. For this purpose the complex stiffness modulus was measured to quantify material stiffness under different temperature and loading conditions providing information on the visco-elasto-plastic material behavior. Fatigue tests were used to determine the progressive and localized material damage caused by cyclic loading. The experimental results indicate that asphalt mixtures prepared with LD slag are suitable for asphalt pavement construction and that in most cases they perform better than conventional asphalt mixtures prepared with Gabbro aggregate.

Drill pipe bridge plug

International Nuclear Information System (INIS)

Winslow, D.W.; Brisco, D.P.

1991-01-01

This patent describes a method of stopping flow of fluid up through a pipe bore of a pipe string in a well. It comprises: lowering a bridge plug apparatus on a work string into the pipe string to a position where the pipe bore is to be closed; communicating the pipe bore below a packer of the bridge plug apparatus through the bridge plug apparatus with a low pressure zone above the packer to permit the fluid to flow up through the bridge plug apparatus; engaging the bridge plug apparatus with an internal upset of the pipe string; while the fluid is flowing up through the bridge plug apparatus, pulling upward on the work string and the bridge plug apparatus and thereby sealing the packer against the pipe bore; isolating the pipe bore below the packer from the low pressure zone above the packer and thereby stopping flow of the fluid up through the pipe bore; disconnecting the work string from the bridge plug apparatus; and maintaining the bridge plug apparatus in engagement with the internal upset and sealed against the pipe bore due to an upward pressure differential applied to the bridge plug apparatus by the fluid contained therebelow

A Novel Concrete-Based Sensor for Detection of Ice and Water on Roads and Bridges.

Science.gov (United States)

Tabatabai, Habib; Aljuboori, Mohammed

2017-12-14

Hundreds of people are killed or injured annually in the United States in accidents related to ice formation on roadways and bridge decks. In this paper, a novel embedded sensor system is proposed for the detection of black ice as well as wet, dry, and frozen pavement conditions on roads, runways, and bridges. The proposed sensor works by detecting changes in electrical resistance between two sets of stainless steel poles embedded in the concrete sensor to assess surface and near-surface conditions. A preliminary decision algorithm is developed that utilizes sensor outputs indicating resistance changes and surface temperature. The sensor consists of a 102-mm-diameter, 38-mm-high, concrete cylinder. Laboratory results indicate that the proposed sensor can effectively detect surface ice and wet conditions even in the presence of deicing chlorides and rubber residue. This sensor can further distinguish black ice from ice that may exist within concrete pores.

Review of CO2 Reduction Technologies using Mineral Carbonation of Iron and Steel Making Slag in Malaysia

Science.gov (United States)

Norhana Selamat, Siti; Nor, Nik Hisyamudin Muhd; Rashid, Muhammad Hanif Abdul; Fauzi Ahmad, Mohd; Mohamad, Fariza; Ismail, Al Emran; Fahrul Hassan, Mohd; Turan, Faiz Mohd; Zain, Mohd Zamzuri Mohd; Abu Bakar, Elmi; Seiji, Yokoyama

2017-10-01

Climate change, greenhouse gas effect, and global warming is envisioning to turn more awful and more terrible by year. Since the leading cause of global warming is uncontrolled CO2 in atmosphere. The amount of unused steel slag is expected to increment later on, steel industries is one of the mechanical industries that contribute the CO2 emission. That because this businesses deliver carbon in light of powers reductant and substantial volume of steel. The changes of atmosphere these day is truly developing concern and that make steel creator are confronted with test of discovering methods for bringing down CO2 emission. Malaysia is working decidedly in the diminishment of CO2 gas. There are a few techniques in decreasing the amount of CO2 in the air as underlined by the Intergovernmental Panel of Climate Change (IPCC), an organization under the United Country however CCS is an extremely encouraging innovation to moderate CO2 emission in air. Mineral carbonation is another technique to store carbon dioxide permanently, long term stability and vast capacity.

Bridging Anticoagulation

Science.gov (United States)

... clinical centers in the United States, Canada, and Brazil. A more detailed description of the study is ... Your Personal Message Send Message Share on Social Media Bridging Anticoagulation The BRIDGE Study Investigators Circulation. 2012; ...

Preformed stainless steel crown in special conditions in adults: Two case reports

Directory of Open Access Journals (Sweden)

S Madhu

2015-01-01

Full Text Available Stainless steel crowns (SSC are extensively used in child patients. They are mainly used following the pulp therapy in deciduous teeth. They are also used in multi-surface restoration, as an abutment in space maintainers, correction of anterior tooth cross bite, restoration of hypoplasic teeth, etc. In permanent teeth, they are mainly used as interim restorations following root canal treatment in first molars prior to the eruption of permanent second molars. The main advantage of SSC is its limited chair side time, durability and ease of placement. Patients with conditions such as pregnancy and old age who cannot tolerate multiple and long appointments can greatly benefit from the use of SSC. Though SSC can be used by other dental specialties very effectively, its use seems to be limited to pediatric dentistry. Presented here are few adult cases in which SSC is given with good success.

Bridging the Gap

DEFF Research Database (Denmark)

Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska

Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

Long Span Bridges in Scandinavia

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1998-01-01

The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...

Permanent quadrupole magnets

International Nuclear Information System (INIS)

Bush, E.D. Jr.

1976-01-01

A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. (author)

Quantifying reinforced concrete bridge deck deterioration using ground penetrating radar

Science.gov (United States)

Martino, Nicole Marie

Bridge decks are deteriorating at an alarming rate due to corrosion of the reinforcing steel, requiring billions of dollars to repair and replace them. Furthermore, the techniques used to assess the decks don't provide enough quantitative information. In recent years, ground penetrating radar (GPR) has been used to quantify deterioration by comparing the rebar reflection amplitudes to technologies serving as ground truth, because there is not an available amplitude threshold to distinguish healthy from corroded areas using only GPR. The goal of this research is to understand the relationship between GPR and deck deterioration, and develop a model to determine deterioration quantities with GPR alone. The beginning of this research determines that not only is the relationship between GPR and rebar corrosion stronger than the relationship between GPR and delaminations, but that the two are exceptionally correlated (90.2% and 86.6%). Next, multiple bridge decks were assessed with GPR and half-cell potential (HCP). Statistical parameters like the mean and skewness were computed for the GPR amplitudes of each deck, and coupled with actual corrosion quantities based on the HCP measurements to form a future bridge deck model that can be used to assess any deck with GPR alone. Finally, in order to understand exactly which component of rebar corrosion (rust, cracking or chloride) attenuates the GPR data, computational modeling was carried out to isolate each variable. The results indicate that chloride is the major contributor to the rebar reflection attenuation, and that computational modeling can be used to accurately simulate GPR attenuation due to chloride.

Wide gap, permanent magnet biased magnetic bearing system

Science.gov (United States)

Boden, Karl

1992-01-01

The unique features and applications of the presented electrical permanent magnetic bearing system essentially result from three facts: (1) the only bearing rotor components are nonlaminated ferromagnetic steel collars or cylinders; (2) all radial and axial forces are transmitted via radial gaps; and (3) large radial bearing gaps can be provided with minimum electric power consumption. The large gaps allow for effective encapsulation and shielding of the rotors at elevated or low temperatures, corrosive or ultra clean atmosphere or vacuum or high pressure environment. Two significant applications are described: (1) a magnetically suspended x ray rotary anode was operated under high vacuum conditions at 100 KV anode potential, 600 C temperature at the rotor collars and speed 18000 rpm with 13 mm radial bearing gap; and (2) an improved Czochralski type crystal growth apparatus using the hot wall method for pulling GaAs single crystals of low dislocation density. Both crystal and crucible are carried and transported by magnetically suspended shafts inside a hermetically sealed housing at 800 C shaft and wall temperature. The radial magnetic bearing gap measures 24 mm.

Mechanism of Pitting Corrosion Prevention by Nitrite in Carbon Steel Exposed to Dilute Salt Solutions

International Nuclear Information System (INIS)

Zapp, Philip E.; Zee, John W. van

2002-01-01

The research has developed a broad fundamental understanding of the inhibition action of nitrite ions in preventing nitrate pitting corrosion of carbon steel tanks containing high-level radioactive waste. This fundamental understanding can be applied to specific situations during waste removal for permanent disposition and waste tank closure to ensure that the tanks are maintained safely. The results of the research provide the insight necessary to develop solutions that prevent further degradation

Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

Science.gov (United States)

Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

2008-06-01

The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version.

Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

International Nuclear Information System (INIS)

Yang Caiqian; Wu Zhishen; Zhang Yufeng

2008-01-01

The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version

The use of fibre-reinforced polymers (FRP in bridges as a favourable solution for the environment

Directory of Open Access Journals (Sweden)

Żyjewski Artur

2017-01-01

Full Text Available The purpose of this article is to show the modern engineering, in which sustainability and taking care of ecology play a significant role. The authors are focused on FRP composite materials and their applications in civil engineering. Case studies showing renovation and design of new bridges with the use of FRP are presented and discussed to clarify benefits, which this solution provides. Main advantages of FRP materials in comparison with traditional ones, like concrete or steel are showed. The environmental impact of composites is described with respect to all life cycle of a product. Furthermore, some forms of waste management are covered. Last part of the paper refers to scientific description of the pedestrian bridge made of FRP, which was realized under the Fobridge research grant. The group of researchers headed by professor Chróścielewski from Gdansk University of Technology has developed a design solution of the pedestrian bridge manufactured in one production cycle. Moreover, the footbridge construction contains a significant share of a recyclable material commonly called PET. The article contains main characteristics of the structure and production process based on the resin infusion.

Integral Abutment and Jointless Bridges

Directory of Open Access Journals (Sweden)

Cristian-Claudiu Comisu

2005-01-01

Full Text Available Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones that have their superstructure cast integrally with their substructure. The jointless bridges cost less to construct and require less maintenance then equivalent bridges with expansion joints. Integral bridges present a challenge for load distribution calculations because the bridge deck, piers, abutments, embankments and soil must all be considered as single compliant system. This paper presents some of the important features of integral abutment and jointless bridge design and some guidelines to achieve improved design. The goal of this paper is to enhance the awareness among the engineering community to use integral abutment and jointless bridges in Romania.

Seismic Material Properties of Reinforced Concrete and Steel Casing Composite Concrete in Elevated Pile-Group Foundation

Directory of Open Access Journals (Sweden)

Zhou Mi

2015-09-01

Full Text Available The paper focuses on the material mechanics properties of reinforced concrete and steel casing composite concrete under pseudo-static loads and their application in structure. Although elevated pile-group foundation is widely used in bridge, port and ocean engineering, the seismic performance of this type of foundation still need further study. Four scale-specimens of the elevated pile-group foundation were manufactured by these two kinds of concrete and seismic performance characteristic of each specimen were compared. Meanwhile, the special soil box was designed and built to consider soil-pile-superstructure interaction. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the RC specimens. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. The pinching effect of first two specimens is more obvious than latter two specimens and the hysteretic loops of reinforced specimens are more plumpness. The pseudo-static tests also provided the data to quantitatively assessment the positive effect of steel casing composite concrete in aseismatic design of bridge.

Bridge deterioration models to support Indiana's bridge management system.

Science.gov (United States)

2016-02-01

An effective bridge management system that is equipped with reliable deterioration models enables agency engineers to carry out : monitoring and long-term programming of bridge repair actions. At the project level, deterioration models help the agenc...

Automatic Bridge Control System

OpenAIRE

M. Niraimathi; S.Sivakumar; R.Vigneshwaran; R.Vinothkumar; P.Babu

2012-01-01

Bridge vibration control is an important issue whose purpose is to extend the structural service life of bridges. Normally, the bridge is modeled as an elastic beam or plate subject to a moving vehicle. However, the moving truck on a bridge is a complicated problem that must still be researched. In this paper, wepropose a new method, to overcome the huge load in the bridge a load cell is used at the entry which will monitor the load continuously at both ends. To escape from the heavy water fl...

A Novel Concrete-Based Sensor for Detection of Ice and Water on Roads and Bridges

Directory of Open Access Journals (Sweden)

Habib Tabatabai

2017-12-01

Full Text Available Hundreds of people are killed or injured annually in the United States in accidents related to ice formation on roadways and bridge decks. In this paper, a novel embedded sensor system is proposed for the detection of black ice as well as wet, dry, and frozen pavement conditions on roads, runways, and bridges. The proposed sensor works by detecting changes in electrical resistance between two sets of stainless steel poles embedded in the concrete sensor to assess surface and near-surface conditions. A preliminary decision algorithm is developed that utilizes sensor outputs indicating resistance changes and surface temperature. The sensor consists of a 102-mm-diameter, 38-mm-high, concrete cylinder. Laboratory results indicate that the proposed sensor can effectively detect surface ice and wet conditions even in the presence of deicing chlorides and rubber residue. This sensor can further distinguish black ice from ice that may exist within concrete pores.

Field performance of timber bridges. 5, Little Salmon Creek stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; J. A. Kainz; G. J. Porter

The Little Salmon Creek bridge was constructed in November 1988 on the Allegheny National Forest in Pennsylvania. The bridge is a simple span, single-lane, stress-laminated deck superstructure that is approximately 26-ft long and 16-ft wide. The bridge is unique in that it is the first known stress-laminated timber bridge to be constructed of hardwood lumber. The...

Field performance of timber bridges. 9, Big Erick`s stress-laminated deck bridge

Science.gov (United States)

J. A. Kainz; J. P. Wacker; M. Nelson

The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock...

True stress control asymmetric cyclic plastic behavior in SA333 C-Mn steel

International Nuclear Information System (INIS)

Paul, Surajit Kumar; Sivaprasad, S.; Dhar, S.; Tarafder, S.

2010-01-01

Asymmetric cyclic loading in the plastic region can leads to progressive accumulation of permanent strain. True stress controlled uniaxial asymmetric cycling on SA333 steel is conducted at various combinations of mean stress and stress amplitude in laboratory environment. It is investigated that fatigue life increases in the presence of mean stress. Plastic strain amplitude and hysteresis loop area are found to decrease with increasing mean stress. A huge difference of life and ratcheting strain accumulation is found in engineering and true stress controlled tests.

31 CFR 515.335 - Permanent resident alien.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States. [61 FR 37386, July 18...

Hydraulic modeling of flow impact on bridge structures: a case study on Citarum bridge

Science.gov (United States)

Siregar, R. I.

2018-02-01

Flood waves because of the rapid catchment response to high intense rainfall, breaches of flood defenses may induce huge impact forces on structures, causing structural damage or even failures. Overflowing stream that passes over the bridge, it means to discharge flood water level is smaller than the capacity of the river flow. In this study, the researches present the methodological approach of flood modeling on bridge structures. The amount of force that obtained because of the hydrostatic pressure received by the bridge at the time of the flood caused the bridge structure disrupted. This paper presents simulation of flow impact on bridge structures with some event flood conditions. Estimating the hydrostatic pressure developed new model components, to quantify the flow impact on structures. Flow parameters applied the model for analyzing, such as discharge, velocity, and water level or head that effect of bridge structures. The simulation will illustrate the capability of bridge structures with some event flood river and observe the behavior of the flow that occurred during the flood. Hydraulic flood modeling use HEC-RAS for simulation. This modeling will describe the impact on bridge structures. Based on the above modelling resulted, in 2008 has flood effect more than other years on the Citarum Bridge, because its flow overflow on the bridge.

Seismic energy dissipation study of linear fluid viscous dampers in steel structure design

Directory of Open Access Journals (Sweden)

A. Ras

2016-09-01

Full Text Available Energy dissipation systems in civil engineering structures are sought when it comes to removing unwanted energy such as earthquake and wind. Among these systems, there is combination of structural steel frames with passive energy dissipation provided by Fluid Viscous Dampers (FVD. This device is increasingly used to provide better seismic protection for existing as well as new buildings and bridges. A 3D numerical investigation is done considering the seismic response of a twelve-storey steel building moment frame with diagonal FVD that have linear force versus velocity behaviour. Nonlinear time history, which is being calculated by Fast nonlinear analysis (FNA, of Boumerdes earthquake (Algeria, May 2003 is considered for the analysis and carried out using the SAP2000 software and comparisons between unbraced, braced and damped structure are shown in a tabulated and graphical format. The results of the various systems are studied to compare the structural response with and without this device of the energy dissipation thus obtained. The conclusions showed the formidable potential of the FVD to improve the dissipative capacities of the structure without increasing its rigidity. It is contributing significantly to reduce the quantity of steel necessary for its general stability.

Creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders; Nishuketa gosei kozo shachokyo no creep kaiseki to nejiri shindo kaiseki

Energy Technology Data Exchange (ETDEWEB)

Hoshino, M. [Nihon University, Tokyo (Japan). College of Science and Technology

1996-07-21

This paper describes the creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders. The girder is composed of the concrete slab and the steel girder. I-girders are placed at both edges of the profile. Such a type of bridge was investigated. As the stress migrates by the creep of concrete slab, it is necessary to evaluate the influence of this creep precisely in designing. In the analysis, the composite girder was expressed not by the single member, but by the binary member consisting of concrete member and steel member. Two methods were employed, i.e., method A in which both members are connected by the rigid body beam and method B in which the profile of concrete is converted into the profile of steel. The method A provided better accuracy, but the method B was often sufficient. Torsional rigidity of the open profile structure was much smaller than that of the box profile. As the torsional natural frequency was low, proper torsional vibration analysis was indispensable especially from the viewpoint of wind resistance. Two methods were employed, which utilize the vibration analysis method for general space frame structures. Results of both methods were agreed mutually, but the second method provided better calculation efficiency. 10 refs., 9 figs., 6 tabs.

Lawful Permanent Residents - Annual Report

Data.gov (United States)

Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

Adoption of CO2 laser cutting system for bridge factory. Kyoryo kojo ni okeru CO2 laser setsudan system no tekiyo

Energy Technology Data Exchange (ETDEWEB)

Hata, A.; Ogaya, S.; Tamaoki, N. (NKK Corp., Tokyo (Japan))

1994-05-01

This paper describes a cutting process structured for an objective of accuracy improvement and high-speed automation of cutting processes for thin sheet steels used for bridge building. Objects of the cutting process are such thin sheet steels as lateral ribs (with a thickness of about 9 mm to 14 mm) with complex shapes and a large number of edges to be cut. The process lines consist of two lines for large member and small member cutting. The paper details the numerical controls including the chart system, 'BRISTLAN' that has been developed previously, a CAM information preparing system, and a CAM system. The process is capable of a scheduled treatment of up to eight steel sheets at one time by instructing two corners of steel sheets arranged on a slat conveyor. Cutting lengths of 800 m to 900 m per day have been recorded currently. Cutting speed for a S 400 shot-blast steel sheet with a thickness of 12 mm is 750 m/min with a laser output of 2000 W. In a treatment with a common cutting system to make outlines of each member uniform, the cutting length was decreased by 6.7% to 35%, and the yield was improved by 1.9% to 2.9%. 5 figs., 3 tabs.

21 CFR 886.4445 - Permanent magnet.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove metallic...

Light-weight aluminium bridges and bridge decks. An overview of recent applications

NARCIS (Netherlands)

Maljaars, J.; Soetens, F.; Kluyver, D. de

2008-01-01

The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these

Development of Analytical Method for Predicting Residual Mechanical Properties of Corroded Steel Plates