Study On Seismic Reinforcement Effect Of Double-column Bridge Pier Based On Pushover Analysis

China is located in the world’s two major seismic zones,namely the Pacific Rim Seismic Zone and the Eurasian Seismic Zone,is one of the most active seismic areas in the global continental region.Compared with the requirements of the current seismic design code for bridges in China,the majority of highway bridges in service in China have different degrees of inadequate seismic capacity,which leads to the weak seismic capacity of bridges in the highway network in China.As a lifeline project,once a catastrophic earthquake occurs to the bridge,it will cause great direct and indirect economic losses.A large number of seismic damage data at home and abroad also show that the study of seismic reinforcement of bridges has important value and significance.The analysis of earthquake damage and force shows that bridge piers generally enter the plastic stage,while the superstructure is mostly in the elastic stage in strong earthquake.And if the pier column is seriously damaged or collapsed will lead to the collapse of the whole structure,so the performance of the bridge pier column has more important significance for the safety of the whole structure.Therefore,the seismic reinforcement of bridge pier becomes the key part of the seismic reinforcement of the structure.Based on the Pushover analysis method,a double-column bridge pier is simplified and analyzed,the seismic performance evaluation,seismic reinforcement and reinforcement parameters on the seismic performance of the bridge double-column piers are studied,in order to find the appropriate reinforcement method for the piers and provide a reference for the choice of the reinforcement method.The following work is the main work of this paper:1.The research status of seismic reinforcement methods for bridge piers is introduced.The basic principle,basic assumption and implementation steps of Pushover analysis method are displayed in detail;2.The simplified finite element model of the double-column bridge pier of an old bridge is established,and Pushover analysis method is applied to evaluate the seismic performance of the pier,combined with the description of the performance point plastic hinge state.The results show that the seismic performance of the bridge pier is insufficient,and it needs to be strengthened;3.The structure member strengthening with R.C & P.C,structure member strengthening with bonded steel plate and structure member strengthening with CFRP are used to strengthen the assessed pier that do not meet the requirements of seismic performance.The seismic performance of the strengthened piers is analyzed.The influence of the parameters such as the thickness of new concrete,reinforcement way and reinforcement height of structure member strengthening with R.C & P.C on the reinforcement effect is studied.The influence of the parameters such as the thickness of steel plate and the interval length of structure member strengthening with bonded steel plate on the reinforcement effect is studied.The influence of the thickness of CFRP and the interval length of structure member strengthening with CFRP on the reinforcement effect is studied.The construction process and economy of each reinforcement method are compared.