Seismic Response Analysis Of A Rigid Frame-single Ribbed Arch Combination Bridge

The rigid frame-single ribbed arch combination bridge is a new type of bridge that has emerged in recent years,witch has beautiful bridge shape,good performance,large span capability and high bearing capacity.It has a broad development in the field of bridge engineering construction prospect.In this paper,based on the rigid frame-single-ribbed arch bridge of a city rail transit,the seismic response analysis is carried out to understand the seismic characteristics of the structure.The main contents of the research analysis are as follows:1.Briefly describe several methods for seismic response analysis of bridges,including: static method,response spectrum method and time-course analysis method,and compare and summarize the above methods.2.The full-bridge finite element model is established by Midas/Civil.The two models are divided into piles and no piles.The natural vibration characteristics of the arch bridges are calculated respectively,and the influence of piles and soils on the natural vibration characteristics of the structures is analyzed.3.The response spectrum analysis of the whole bridge includes four conditions: longitudinal,horizontal,vertical + vertical,horizontal + vertical.The effects of longitudinal and lateral seismic waves on the internal forces of the key parts and the effects of vertical seismic waves on the bridge are compared.The pile model and the pile-free model are analyzed to analyze the specific influence of pile and soil action on the stress of key parts.4.The time course analysis of the whole bridge is carried out,and the results of the response spectrum analysis are compared and summarized.The research results show: The lateral stiffness of the arch rib is weak and it is prone to lateral vibration,which is the focus of structural and seismic design.The geological distribution of the whole bridge has a great influence on the dynamic characteristics of the structure,and the influence of the pile-soil effect cannot be ignored.After considering the effect of pile soil,the internal forces of the main pier and the front and rear cantilever roots have changed greatly.The in-plane bending moment of the main pier is reduced,and the front and rear cantilever is increased.The seismic design of the front and rear cantilever roots should be noted.The results of the time history analysis are smaller than the response spectrum.