Study On Effects Of Ground Velocity And Ground Displacement On Seismic Responses Of Long Span Cable-Stayed Bridge

Along with the city's modernization, the transportation network plays more and more important role in city's lifeline system. The cable-stayed bridge is of importance in city's transportation network as one of the most popular long-span bridges as well. So far, we have constructed 30 cable-stayed bridges, which is next only to Germany and Japan, and is situated the third in the world.At present, we only consider the acceleration response spectrum and PGA when analyses the seismic response of long span bridge whose span length is longer than 150 meters. Even if there are some conclusions about the effects of velocity pulse on structures, but it hasn't been applied in practice yet, and the effect of PGD on structures is barely on research.The cable-stayed bridge whose main span surpasses 150 meters is of more flexibility, and belongs to long period structure. It is very sensitive to the variety of velocity and displacement of the seismic motion. Therefore, this paper will aim at the research of the effect of velocity and displacement on long period structure, that is to say, in the condition of the same response spectrum and PGA, we will investigate the effect of the difference of velocity or displacement on cable-stayed bridge.First, According to the target response spectrum, 3 groups of synthesized seismic motions are generated respectively, the parameters are: 1000 cm/s~2, 300cm/s, 500cm; 1000 cm/s~2, 300cm/s, 250cm; 1000 cm/s~2, 150cm/s, 500cm, and there are ten synthesized seismic motions in each group. Then the PGA of 3 groups are scaled to different values so that they make the cable-stayed bridge in elastic or inelastic stage.Based on the analysis results, we can draw the conclusions that:(a) When in elastic stage, there is barely difference about the response of bridge which is caused by velocity and displacement of input seismic motions.(b) When in inelastic stage, PGV, PGD, the effective maximal velocity and the effective maximal displacement will bring different effects on the structures: (1) when...