The Seismic Response Analysis And Earthquake-reduction Design Research On The Single Tower Cable-stayed Bridge

It is well known, in general, that the long-span cable-stayed bridge is the hinge of transportation, which is heavily invested in, used frequently and has important influence on national economy. Once destroyed, it will cause huge economic lose and heavily influence earthquake disaster reduction and repair of disaster area which damaged in an earthquake. How to improve the earthquake resistance ability of bridges is although an important subject for research as well as the target for pursuing.Therefore it is very important to adopt the correct and effective earthquake reduction design to make sure the safety of the structure under earthquake.In making shock earthquake reduction design of cable-stayed bridge, the leading thinking is that, in the earthquake, the internal force and displacement of the cable-stayed bridge are the smaller the better. However, traditionally, if a cable-stayed bridge was designed without any effective seismic fortification measures, small internal force always accord with great displacement, and vice versa.This paper takes Xinjiang Bridge in Jiangxi Ying-tan as background, three finite element models for the single tower cable-stayed bridge by MIDAS/Civil are established, which are without earthquake-reduction measure, with elastic link device (such as cable retainer) and with viscous damper. Then, through modal analysis, the paper investigated the impacts of elastic cable device and viscous damper on structure dynamic characteristic. And through time-history analysis, the paper has studied reduction of seismic response effectiveness of elastic cable device and viscous damper, and discussed the elastic cable device and viscous damper of the design parameters of the earthquake-reduction effect to the change impact. Then, the rational elastic stiffness of the elastic cable device and the rational damping coefficient C and damping exponent a is confirmed through the parameter sensitivity study.The analysis indicates that both elastic cable device and the viscous damper with rational parameters may reduce the seismic displacement significantly, and reduce internal forces in the same time. Finally, synthetically analysis is carried on to decide that setting viscous damper is better for this bridge. The design can improve the cable-stayed bridge seismic capacity and durability, which agrees with the idea of earthquake-reduction design, and can be used as reference for other bridges seismic analysis and earthquake-reduction design.