Advanced Materials Research Vols. 1065-1069

Abstract: Stayed-cable was being considered as an important component of cable-stayed bridge, with characteristics of its low quality, stiffness and damping, among which rain-wind-induced vibration brings the most serious damage in its high amplitude because of its easy conditions to meet. This paper based on the theory of stayed-cable rain-wind-induced vibration, Through comparing different aerodynamic control measures in wind pressure test of ZhiJiang Bridge cable, this paper analyses the variation rules of two and three dimensional cable surface pressure distribution in different aerodynamic measures and cable aerodynamic coefficient in different surface conditions. The results show that: the wind angle influenced surface wind pressure coefficients and aerodynamic coefficient larger, especially between 25 ° and40 °; when the water was between 40 ° and70 °, the aerodynamic coefficient changed obviously, may happen galloping; It recommend that the cable helix parameter K1 was larger and K2 was between 0.01 and 0.03.

Abstract: For different structural system of cable-stayed bridge, the dynamic characteristics have obvious difference under seismic load. Dynamic time-history analysis of earthquake was applied, and the EI Centero seismic wave with modified peak acceleration was chose as the earthquake acceleration time-history input. As Jiangsu Siyang special-shaped single tower cable-stayed bridge for engineering background, considering geometric nonlinear of structure, the differences of dynamic characteristics of cable-stayed bridge structures were gained under two different situations. The single longitudinal seismic ground motion was chose under the first situation, while the longitudinal, lateral, and vertical seismic ground motion are introduced. For floating system, the displacements are the largest and the inner forces are the smallest. For rigid frame system, the displacements are the smallest and the inner forces are the largest. The others are not much difference. Comprehensively, semi-floating system has better performance under seismic load.

Abstract: First, conducting static load tests for a 5 span bridge, then carry on application research for the bridge based on the embedded carbon fiber (CFRP) reinforced flexural reinforcement aiming at the shortcomings of its flexural properties, At last, the effectiveness of strengthening reinforced concrete beam that reinforcement by embedded CFRP has been discussed. The results show that embedded CFRP reinforcement beam can make full use of the characteristics of high strength of CFRP, which can improved obviously the capacity of the reinforced beam and the maximum increased capacity can reach 13.2%. In addition, the application of the embedded CFRP reinforcement technology has been discussed, which provides a meaningful reference for the development of the technology.

Abstract: Through the construction monitoring of a large-span bridge which is a single box single room PC continuous box-girder bridge with corrugated steel webs, suitable methods are summed up. Finite element simulation was combined with field measurements data to calculate the model elevation of construction. By adjusting and control the model elevation, the linear shape of the bridge met the design requirements. By collecting strain data of the key sections of the bridge, abnormalities that may exist could be detected timely so that early warning could be made and construction safety and quality could be ensured.

Abstract: In this study, dynamic behavior of cable-stayed bridge under moving vehicle and train was analyzed. The parameters considered are the main span length of bridge and the existence of intermediate pier at side span. For the parametric analysis, cable-stayed bridges with 400m and 700m main span (with and without the intermediate pier at side span) were selected. From the vehicle/train-bridge interaction analysis, the intermediate pier was found very effective to reduce the dynamic amplification of girder and stay-cables.

Abstract: This paper investigates the dynamic properties of each sub-system of a coupled railway train-bridge interaction system. Both spatial beam-plate model and spatial grillage model are built for a long-span dual-deck cable-stayed railway bridge by use of finite element method. The railway train is modeled as a mass-spring-damper system. Then free vibration equations are established based on the finite element models and then subspace iteration method is employed to calculate the dynamic properties for each sub-system. Results show that the spatial grillage model agrees well with the spatial beam-plate model in terms of mass and stiffness distribution. The spatial beam-plate model serves as benchmark solution and the grillage model as a tool for dynamic responses of the coupled system due to its computational efficiency. It also shows that first modes of both the railway train and long-span bridge are lateral direction, which indicates that the train may experience much response in lateral direction. Therefore attention should be drawn to the lateral running stability and safety of railway train due to the coupling effect between the bridge and railway train.

Abstract: In the approach spans of Quanzhou Bay Cross-sea Bridge, these standard spans are 50m or 70m , width is 20.05m.The approach spans have been built by using short Line segments precast and erection method. This is the first application in the cross sea bridges. According to characteristics of this project, the research on prefabrication and erection technology of wide box girders has been carried out to solve the technical problems in the process of construction. The research show that: 1)In precasting process , the vertical deformation of wide box girder is very small under dead load and temperature load etc. so the influence of prefabrication and erection accuracy can be ignored; 2)The temporary anchor using prestressed steel strand better than planished steel; 3) When using epoxy gasket to adjust geometric line shape, the thickness of cemented layer has a great influence on the linear adjustment;4)The epoxy gasket and bridge erecting machine should be used together, Alignment adjustmen could obtain satisfactory results.

Abstract: Based on bridges routine examination, special detection is in-depth and meticulous testing that according to the disease characteristics, using some expertise technology and testing equipment for steel corrosion, concrete carbonization, the thickness of the protective layer and component quality to some key parts or typical bridge opening. Bridge condition of technology can be controlled more fully and accurately through a special bridge inspection, combined with conventional test results on the status of a comprehensive assessment of structures. This may provide technical data for the next bridge inspection count and load test, moreover, according to the variation of the data in the field test, it may dedicate variation characteristic and influencing factors for damage of structural durability from these special detections.

Abstract: According to the status quo detection of Wang Tong Gang Bridge, with the research of the reinforcement schemes, a reinforcement scheme of the bridge is put forward, through which the increasing bearing capacity of the bridge was tested.

Abstract: The dynamic characteristics of Tukan Wujiang Bridge are analyzed numerically. The bridge, which is still under construction, is a continuous rigid frame bridge with high-piers and long-span in Wulong County, Chongqing, China. A spatial finite element model is established for the bridge with the finite element software ABAQUS. The natural vibration characteristics and effective modal participation mass of the bridge in the built-up case is obtained. The variation of dynamic characteristics of continuous rigid frame bridge subjected to the dynamic earthquake loading is studied, and the number of modes necessary to the vibration mode combination when applying the response spectrum method under the earthquake is obtained. In addition, the seismic response of the bridge is analyzed with both the response spectrum method and the time-history method, and the maximum response of structure under various probability of earthquake is obtained. The results of the two methods are compared. The comprehensive seismic performance of the bridge is analyzed and evaluated. The results show that the seismic performance of the rigid frame bridge satisfies the expected design performance.