Seismic Vulnerability Analysis For Concrete Continuous Beam Bridge In Typical City

With the rapid development of national economy,the construction of highway transportation network is accelerating,and more and more bridges are built.As a "hub" project in the transportation network system,the safety requirements of bridge engineering should undoubtedly be the highest,and the importance of seismic fortification is self-evident.Once the bridge located at the key node is destroyed in the earthquake,it will not only cause direct economic losses,damage to the function of the transportation system,or even interrupt traffic,but also cause huge economic losses,and bring greater difficulties to emergency relief.This paper is part of the national key research and development plan "Key Technologies Research on Operation and Maintenance Safety of Typical Urban Transportation Infrastructure".It studies and analyses the seismic vulnerability of typical urban concrete continuous beam bridges,and provides technical support for seismic performance evaluation of bridge engineering.In this paper,the vulnerability of typical urban concrete continuous girder bridges and the whole bridge along and across the bridge are analyzed,and the corresponding vulnerability curves are obtained.The main contents of this paper include:(1)Summarize the forms of seismic damage of bridge structural components and the methods of seismic performance evaluation,review and summarize the vulnerability analysis methods,and summarize the current research status of vulnerability analysis at home and abroad.(2)Briefly introduce the establishment process of vulnerability curve and the theoretical calculation method for vulnerability analysis,provide theoretical basis for the establishment of theoretical vulnerability curve of components;summarize damage criteria and discuss the selection of seismic wave and the determination of damage index,and provide ideas for the establishment of theoretical vulnerability curve of components.(3)Selecting a continuous girder bridge in a city as a reference bridge,using Midas Civil software to establish a finite element model and calculate seismic response data,as the basis of vulnerability analysis.(4)The vulnerability of bridge vulnerable components under along-bridge seismic excitation is analyzed,and the effects of three different isolation bearings,lead rubber isolation bearings,high-damping rubber bearings and viscous damping isolation bearings on the overall vulnerability curve of fixed piers,bearing systems and bridges are compared.(5)To analyze the vulnerability of bridge vulnerable components under transverse seismic excitation,compare the vulnerability and vulnerability curves of along-bridge and transverse-bridge components,and analyze the impact of three different isolation bearings,viscous damping isolation bearings,lead-core rubber isolation bearings,high-damping rubber bearings on the overall vulnerability curves of fixed piers,bearing systems and bridges.Compare the effects of reducing vulnerability in three forms.Through the above comparison and analysis,the influence law of the arrangement of different isolation bearings on the vulnerability change of bridge components is obtained,which provides basis and ideas for the evaluation of seismic performance of vulnerable components and subsequent reinforcement.