设置拉筋的铁路双柱式桥墩抗震加固分析

为确保双柱式桥墩在地震作用下的安全,以某铁路双柱式桥墩为例,提出了通过设置斜拉钢筋,减小桥墩在地震作用下的内力和位移响应,达到预防性抗震加固的目的。通过对双柱式桥墩进行PUSHOVER分析,求出桥墩屈服曲率和极限曲率及对应的弯矩、位移,并以此作为加固评价指标,评价多遇地震下及罕遇地震下斜拉钢筋对双柱式桥墩的加固效果。通过利用ANSYS有限元分析软件进行非线性时程反应分析,比较了双柱式桥墩在设置加固前后的内力响应、位移响应,研究了加固的必要性和合理性。结果表明:原双柱式桥墩在设置斜拉钢筋后,桥墩在多遇地震作用下处于弹性阶段,墩底内力减小;在罕遇地震作用下桥墩由破坏状态变为屈服状态,满足延性抗震的加固思路。

Analysis on Seismic Reinforcement of Railway Double-column Piers with Cable-stayed Rebar

Taking a railway double-column pier as an example,it is proposed that the internal force and displacement responses of bridge pier under seismic action are reduced by setting the cable-stayed rebar in order to ensure the safety of double-column pier under seismic action and to achieve the goal of preventive seismic strengthening.The Pushover analysis of double-column pier is carried out to calculate the yield curvature and ultimate curvature of the bridge pier,and the corresponding bending moment and displacement.The calculation results are adopted as the reinforcement evaluation indexes to evaluate the reinforcement effect of the cable-stayed rebar on double-column pier under the frequent earthquake and rare earthquake.The ANSYS finite element analysis software is used to carry out the nonlinear time-history response analysis.The internal force responses and displacement responses of the double-column pier before and after reinforced are compared.The necessity and rationality of the reinforcement are studied.The results show that the bridge pier is in the elastic stage and the internal forced at pier bottom is decreased under the frequent earthquake after the original double-column pier is set with cable-stayed rebar.The bridge pier is changed from the destructive state to yield state under the action of the rare earthquake,which meets the idea of ductile seismic reinforcement.