Applied Mechanics and Materials Vols. 178-181

Abstract: Most of the short span suspension bridges with steel truss girders early constructed will approach their design service life. Correctly evaluating the actual service performance is the basic basis of repairing, strengthening and technical reconstruction. First, load-bearing capacity evaluation based on static load test was briefly introduced. Then, combined with Chengnan bridge, the main existing damages and their causations of the bridge were summarized and analyzed. Based on the field detection datum and original design load grade, the finite element mode with some damages was established. Then, by analyzing the calculation results, the scheme of static load test was confirmed. Through comparing the static load test results with the results of upgraded finite element, the actual conditions of the existing bridge structure were evaluated. In order to resume its load-bearing capacity, some of measurements and suggestions of strengthening were proposed.

Abstract: In order to investigate the influence rules of the factors such as: the area of the hole in the steel plate, the cross section area of the transfixion steel bar, the concrete strength and the thickness of the steel plate on the working performance of the PBL shear connectors, the effectiveness of finite element method was verified by comparing the results of the test and that of the finite element method, then the PBL working performance indexes under each influence factor with different values were calculated. The results showed that the area of the hole in the steel plate and the concrete strength were the main influence factors to the elastic ultimate load, the elastic stiffness and the initial yield load of the PBL, the cross section area of the transfixion steel bar had some influence on the elastic stiffness and the initial yield load, the steel plate thickness had some influence on the elastic stiffness and the elastic ultimate slip of the PBL.

Abstract: On the basis of the static and dynamic testing of the bridge, the original structure model and the model based on stiffness reduction of Dongfu Bridge were analyzed and calculated with the finite element method. The main problem that the anti-shear area of the section in the middle pivot position is not enough is found. On the basis of combination of the passive and active reinforcement styles, a reasonable and feasible reinforcement plan on the girder beam of the main bridge is raised. These conclusions have an important reference value on the bridge reinforcement.

Abstract: Temperature in the concrete box girder caused by sunshine has a significant influence on the deflection, stress and strain of the beam. Based on the Xinjiang Bridge, through measuring the deflection, temperature, stress and strain at the largest cantilever stage,then compare the measured results with finite element analysis results to investigate the impact of temperature gradient on the construction of cable-stayed bridge.

Abstract: With a small cross section, a light deadweight and a convenient replaceable tendon, externally prestressed bridges have many special traits compared with other bridges. With a practical case, this paper analyzes the design of externally prestressed steel box girder bridges, which contains the bridge span, beam construction, externally prestressed layout, substructure and construction programs. Through economic, social analysis, discusses the prospects for the application of external prestressing structure .

Abstract: As high performance computing (HPC) becomes a part of the scientific computing landscape, visualizing HPC has become a critical field of its own. This paper describes a visualization cluster solution developed for bridge health monitoring system. First, LCD display, computer with NVIDIA graphic cards, 1G switch and 10G switch are used to build hardware platform; Secondly, Linux operation system, Rocks management software, CGLX middle software is used to display multi-media and 3D data; Finally, OpenSenceGraph 3D graphics engine is used to write high-performance parallel 3D programs. This approach can be used not only for parallel computing, but also for parallel 3D modeling and display. Some application result on bridge health monitoring is given in the end.

Abstract: The actual bowstring arch CFST is taken as the background,the paper using finite element analysis method, researched the shrinkage and creep of combination of steel and concrete structure. Through the use of different countries regulation of shrinkage and creep of concrete, the effects of the structure deflection separately were studied ,then explain the different influence degree of different norms in the calculation of the creep and shrinkage of concrete; The paper also has also put forward the doubt about accurate calculation concrete filled steel tubular structure shrinkage and creep of concrete, it puts forward new requirements for the research and standards about steel tube concrete shrinkage and creep at last.

Abstract: Through simulating the happening location of the fault zone, the structure model is duly simplified, analysing the forced deformation law of the bridge surface with different fault zone position. Because of statically indeterminate structure, continuous beam shall be produced larger additional moment, shear force and torque as a result of displacement in bridge pier, additional stress will be increased with the the increasement of fault zone displacement, especially for the top surface parts of bridge pier. Hence, the corresponding position of the structure and construction measures for reinforcement should strengthened, the overall rigidity of the structure should be improved, and based on the study of the bridge across the fault zone is a simplified, and the actual stress process may be more complex, the investigation on geological condition must be clear, and avoid the bridge structure crossing fault zone.

Abstract: Steel fiber reinforced concrete (SFRC) has many good dynamic performances such as toughness and ductility. However, few studies have focused on SFRC’s application in bearing member of bridge structures. In this paper, pseudo-static cyclic tests of eight pier specimens are carried out to investigate seismic behavior of piers using SFRC. The main variables in the testing are the steel fiber content (volume fraction of 0.0%, 0.5%, 1.0% and 1.5%), the length of SFRC region and the stirrup ratio of piers. Seismic behavior of the test specimens, like the failure pattern, the hysteretic characteristics, the skeleton curves, the ductility and the energy dissipation are investigated experimentally. The results show that, 1) the SFRC pier with the steel fiber volume fraction of 1.0% has much better performance than that with other fiber volume contents, particularly for bearing capacity, hysteretic energy dissipation and ductility; 2) the pier specimen can keep sufficient seismic capacity, in which some stirrups are replaced by steel fibers; and 3) compared with specimen with application of SFRC in entire pier, the specimen with appropriate local application of SFRC in potential plastic hinge region can sustain almost the same seismic properties, such as the ultimate bearing capacity, the stiffness, the ductility and the energy dissipation capacity.

Abstract: The theoretical formulas of the ultimate bearing capacity and critical stress of the deformed steel tube in a CFST arch bridge are gotten by the local section steel tube analysis and the elastic buckling analysis of steel tube, At the same time, the ultimate bearing capacity and critical stress of the deformed steel tube are computed by using ANSYS finite element analysis software and compared, which verifies the theoretical formulas are correctness and feasibility. Finally, a reduction factor formula of the ultimate bearing capacity of the tube before and after deformation is gotten; it directly reflected the reduction level of the ultimate bearing capacity of the deformed steel tube.