Seismic Response Analysis On (43.6+45.2+43.6)m Continuous Rigid Frame Bridge Of Chongqing Metro

With the accelerated pace of infrastructure construction in China,the number of traffic lines is increasing day by day,and various types of bridges have been built,and the number of bridges in China now ranks first in the world.Among the various structural forms of bridges,continuous rigid bridges are widely used due to their structural superiority,especially in the construction of urban rail transit,which is highly favored.Therefore,it is important to analyze the seismic response of continuous rigid frame bridges for urban rail transit,and the influence of structural parameters of double-limb thin-walled piers on the seismic performance of continuous rigid frame bridges is of significant research significance.In this paper,a continuous rigid bridge of one link(43.6+45.2+43.6)m in line 18 of Chongqing metro is used as the research object,and finite element models considering pile-soil action and not considering pile-soil action are established in Midas Civil to analyze the seismic response of the whole bridge respectively,and then the influence of structural parameters of double-limb pier on the seismic performance of the whole bridge is studied.The main works are as follows:(1)The dynamic characteristics of the established two continuous rigid bridge full-bridge models are analyzed by using Midas Civil,and the results of the dynamic characteristics of the two models are compared and analyzed.(2)The response spectrum curves were selected reasonably and the elastic response spectrum method was applied to analyze the seismic response of the two models in the down-bridge and cross-bridge directions to obtain the displacement and internal force response and then analyze the effect of pile-soil action on the continuous rigid bridge.(3)Three seismic waves are selected and amplitude-modulated,and the dynamic time analysis is carried out for the full bridge model considering the pile-soil action,and the displacement and internal force results obtained from the dynamic time analysis are analyzed.It is concluded that the bridge is in elastic working condition under E2 earthquake.(4)Establish a plastic hinge unit at the key position of the bridge pier,adjust the amplitude of the seismic waves again and carry out seismic response analysis to analyze the development process of the plastic hinge under strong earthquake and verify that it meets the ductility requirements.(5)By changing the reinforcement rate of the full-section main reinforcement of the bridge pier and the hoop rate of the pier,the influence of the change on the development process of the plastic hinge of the bridge pier is studied.It was found that under the condition that the hoop rate of bridge pier can guarantee the shear strength of bridge pier,increasing the reinforcement rate of main reinforcement can improve the ductility of bridge pier.(6)For the special structural form of the bridge,different models were established with the height and thickness of the double leg thin-walled pier as variables to analyze the effect of changing the height and thickness of the double leg thin-walled pier on the seismic performance of the whole bridge.