The Seismic Response Analysis Of Asymmetric Continuous Rigid-frame Bridge

In recent years, earthquake disaster frequently occurred in whole world which brought great damage to the safety of life and property for people. Bridge as a lifeline project, its destroy will increase the damage of secondary disasters, leading to more serious losses, grasping and understanding of bridge response under earthquake are meaningful for establishing of a more rational seismic system. Western region of China is a mountain zone, complex terrain, mountains to build bridges, especially the high level bridge; it's easy to appear pier asymmetry for topographical constraints. However, Seismic studies of the asymmetric continuous rigid-frame bridge were fewer. It's hope that this discussion can come of the asymmetric continuous rigid-frame bridge seismic analysis of useful conclusions. This is to provide useful information on the seismic of this bridge for the future.Based on Yantou River Bridge, this paper presents the basic theory of seismic response analysis, on asymmetric continuous rigid frame seismic performance of more comprehensive, in-depth study, the main contents of this paper as follows:1. With professional finite element software Midas, it's to establish a reasonable asymmetric rigid frame of finite element analysis calculation model with beam elements, to consider the along the bridge and vertical, horizontal and vertical seismic action, and solve the seismic response spectrum analysis of the structure force; as the two piers are not only because of the high asymmetry, also a change in cross section, the bridge pier is so special.so only comparing the internal forces of the two piers,there is no sense. It's here obtained the ultimate capacity of special section in1# and 2# pier to compare, it's aim to enable materials play maximize performance.2. Then time-history analysis method to solve the structure of the internal forces under earthquake. Based on the bridge model of asymmetric continuous rigid frame, it's using the Taft wave closing to natural period and peak acceleration with site, and using the same conditions as the response spectrum analysis:the along the bridge and horizontal seismic action to solve the internal force with structure under earthquake, compared with the response spectrum method, the results showed that the result with response spectrum analysis is larger than time-history analysis, which proves response spectrum analysis to be reliable. 3. Change the stiffness of asymmetric continuous rigid frame bridge, creating a new model, using response spectrum analysis to find the effect when changing the stiffness of the structure under earthquake impact. Its found obvious effect which to change the short pier stiffness than high pier. while changing the pier rigidity impacts the effect of internal forces greater than the effect of displacement.4. Change the height of asymmetry continuous rigid frame bridge, creating a new model, using response spectrum method to find the effect under earthquake impact when changing the high pier height of different sections with the structure. The results showed that increased height with box section of high pier, which impacts the effect with low pier than high pier.