单轴对称截面桥墩弹塑性地震响应研究

Study on Elastic-plastic Earthquake Response of Monosymmetry Section Pier

基于OpenSees软件,采用弹塑性纤维梁柱单元建立墩柱模型,考虑上部梁体重量、隔震支座及材料非线性的影响,采用IDA增量动力分析法对某单轴对称截面桥墩进行了结构弹塑性地震响应分析。计算结果表明,单轴对称截面的桥墩在单向地震作用下产生双向弯曲现象,在垂直于对称轴地震激励作用下,桥墩的双弯曲系数随着PGA的增加后降低,当PGA达到某个值之后,双弯曲系数不再有过大的变化,对于指导该类桥梁设计具有一定的参考意义。

Based on the software OpenSees,the elastic-plastic fiber beam-column element is used to establish the pier column model.Considering the influences of upper beam weight,shock insulation support and material nonlinearity,the increment dynamic analysis(IDA)method is used to analyze the structural elastic-plastic earthquake response of a monosymmetry section pier.The calculation result shows that two-way bending is found when a monosymmetry section pier is under the unidirectional seismic action.Under the seismic excitation perpendicular to the axis of symmetry,the double-bending coefficient of pier will be reduced with the increment of PGA.After PGA reaches a value,the double-bending coefficient will not be greatly changed,which provides some references for guiding the design of the similar bridges.