Analysis Of The Seismic Response With A Single Cable Plane And Sparse Harp Cables Of Truss Beam Cable-stayed Bridge

With the rapid development of rail transport construction of Chongqing, city like Chongqing which surrounded by two rivers needs river-crossing bridges. According to the future developing trend of Chongqing, the new cross river bridge will be constructed to use as light-railway and highway combined bridge. In this way it not only can meet the requirements of rail traffic, but also can enrich and ease the urban traffic. In urban areas with the light-railway and highway dual-use bridge, in addition to considering the applicability of the bridge structure itself, but also to be considered compatible with the urban environment.This paper aim to get some useful results by the response analysis of the engineering example when a single cable plane and sparse harp cables of Truss Beam cable-stayed bridge makes seismic design in similar area. Through this analysis we can provide some beneficial reference for such bridges in similar area. The main research contents and results are as follows:① Setting up finite element calculation model and, analyzing dynamic characteristics. We can find out that whether consider pile-soil interaction has significant influence for model’s natural period especially 3~6 step.②Using the design spectrum method for seismic response analysis of bridge,and Use the CQC modal combination method, Conducted along the bridge, transverse direction, the vertical bridge to respectively and two bridges to the most unfavorable combination of seismic response analysis conditions.To analyse of the similarities and differences bedrock horizontal peak ground acceleration response spectrum of bridge seismic response in the same time.The result shows :under the action of the transverse seismic vibration input,internal force and displacement display the maximum response.In the most unfavorable combined effect input action,as the result of vibration modes are excited,the analysis of the structure in various parts are large than the result of one-way input.The largest forced part of the bridge is P1 pier bottom,and the largest deformed part of the bridge appears in the top of the tower pier.The result of using the bedrock horizontal peak ground acceleration response spectrum is smaller than the value of design spectrum.③To analyse the DongShuiMen River bridge by time-history method, obtaining the preliminary conclusions accord to the response spectrum method,conducting the seismic response analysis in three separate directions and the direction most unfavorable combination of the important position,then get the time history analysis curve of the corresponding internal force and displacement of the key location and the maximum response,including to conduct the seismic checking for bridge.Above of all,the results show the DongShuiMen River bridge in seismic design level(fortification level 7) is safe.