海洋不同暴露环境下RC桥墩抗震性能分析

Seismic performance analysis on RC bridge piers under different marine erosion environment

为研究海洋环境下钢筋锈蚀、混凝土强度降低等材料性能退化导致桥墩结构抗震性能演化的规律,采用OpenSees软件分别建立了海洋环境下大气区、潮汐浪溅区和水下区3种不同暴露环境下RC桥墩的有限元模型,对3种不同暴露环境的RC桥墩分别进行了延性分析、滞回耗能分析和地震易损性分析,得到不同暴露环境下桥墩结构的滞回耗能曲线和易损性曲线。结果表明:3种环境下,随着使用年限的增加,各性能均开始不同程度的改变。桥墩结构在潮汐浪溅区抗弯能力下降幅度最大,水下区下降幅度最小;潮汐浪溅区墩底剪力下降速度最快,大气区下降速度较快,水下区抗剪能力下降速度最慢;潮汐浪溅区的地震易损性增幅最为明显,大气区增幅较为明显,水下区变化相差不大;不同损伤状态的地震易损性均在增长。

In order to study the seismic performance evolution law of bridge pier structure caused by material performance deterioration such as rebar corrosion and concrete strength reduction under the marine environment,the OpenSees finite element software is used to respectively establish three different finite element model of RC bridge piers including atmospheric zone,tidal wave splash zone and underwater zone under the marine environment. Based on the analysis on ductility,displacement & hysteretic energy and seismic vulnerability of the RC bridge pier in three different exposed environments,the displacement & hysteretic energy curve and vulnerability curve of the bridge pier structure under different exposed environments are obtained. The results show that with the increase of service life period,the bending resistance of the bridge pier structure at the tidal wave splash zone sees the largest decrease,and the bending resistance at the underwater zone sees the smallest decrease. With the increase of the service life period,the anti-shear performance at the bottom of the bridge pier at the tidal wave splash zone sees the fastest decreasing rate,and the anti-shear performance at the underwater zone sees the slowest decreasing rate,and the seismic vulnerability at the tidal wave splash zone sees the most obvious increase. The seismic vulnerability of bridge pier structure under the exposed environment at the atmospheric zone sees more obvious increase,while the changes at the underwater area sees no different increase. The bridge piers structure under different exposed environments is increasing with the increase of service life period,and the seismic vulnerability with different damage states is increasing too.