Analysis Of Seismic Vulnerability Of City Overpass Curve Box Girder Bridge

In recent decades,the world within the scope occurred many times larger and destructive earthquakes,These large earthquakes are no exception caused the enormous damage to traffic system.While due to the bridge is located in the hub location in the traffic system,it is an extremely important role in the social and economic development,people's life and in the risk and disaster.And bridge can repair of damage within a short period of time is poor than the pavement structure,so the bridge is the key links in earthquake disaster loss assessment,and the consequences of any damage to bridge is more serious than the normal pavement structure.In the city,the small radius curve beam bridge,for cities to reduce land utilization and improving vehicle vision and aesthetics are of great help,so get a lot of application in city overpass.The curved girder Bridges and city overpass hub location are usually located in urban traffic system,in the event of damage,could lead to urban traffic paralysis of large area.In view of the curved girder irreplaceable importance in the urban traffic system,earthquake damage to the curve girder bridge role more and more get the attention and research of the experts and scholars.Because of the structure seismic vulnerability analysis for predicting the seismic performance of structure,the seismic design and reinforcement of the structure and maintenance decision has important application value,this paper will be based on several large earthquake in recent decades of curved girder damage to expound the research significance,this paper presents the definition of structure seismic vulnerability and the seismic vulnerability assessment method in the field of major development of a comprehensive review,and the category of vulnerability analysis method,advantages and disadvantages and application to make a summary and discussion.Through the description and analysis of vulnerability curve,lay the framework for the following research work.In addition,in accordance with the specification requirements and seismic wave characteristics to choose the appropriate seismic records,and adjusted to the identify format for the large finite element software MIDAS/Civil.After the defined material constitutive model,through the bending moment-curvature analysis to evaluate the performance of the curve beam bridge pier column section,according to the result of bending moment-curvature analysis calculates the displacement ductility ratio as the damage index of the damage status of the critical value.This article refer to a lot of information about city of curved girder damage in the earthquake,Hwang and Liu Jingbo for reference for the new Madrid region of a three span continuous girder bridge based on the nonlinear dynamic time history analysis of structure vulnerability model,based on a curved ramp bridge in the west of China,a curve by MIDAS/Civil finite element software of grillage method,change the radius of curvature of the curve beam bridge and pier height model respectively,the response spectrum analysis of curved girder and nonlinear dynamic time history analysis,again according to the results of regression analysis,then establish structure reaction probability function,calculation of structure under different intensity earthquakes seismic effect beyond the probability of more than a failure state,finally draw the peak ground acceleration PGA selected as variables of seismic vulnerability curve,according to the two factors of vulnerability curve comparison,and then make the radius of curvature of the forces of the curved girder and pier height on the influence of the vulnerability assessment.