考虑双向耦合效应的桥墩非线性地震反应分析

Analysis of Nonlinear Seismic Response of Bridge Piers on Consideration of Bi-directional Coupled Effect

研究目的:为了研究钢筋混凝土桥墩在双向地震激励下的动力响应特性,采用自主研发的纤维梁柱单元模拟平台FENAP,对一双向加载下钢筋混凝土桥墩振动台试验进行数值模拟,并与试验结果进行对比。此外还模拟单向地震动加载下桥墩的动力时程响应,与双向加载结果进行比较分析,得到单向与双向加载条件下二者的动力响应差异。研究结论:(1)双向加载下钢筋混凝土桥墩振动台试验数值模拟分析与试验结果对比表明:FENAP平台可有效考虑桥墩的双向弯曲耦合效应,能有效预测墩顶位移时程响应峰值的大小和出现时间,获得较为准确的数值模拟结果;(2)与单向加载下的桥墩的时程响应相比后可得出结论:双向地震下得到的位移响应大于单向,而加速度响应小于单向;(3)对于桥墩构件而言,双向地震的多维耦合作用是不可忽略的,仅进行单向地震响应分析会高估构件的刚度,低估构件的位移响应;(4)本文的研究成果可应用于公路、铁路、城市轨道交通等大跨连续梁桥的抗震设计。

Research purposes： To analyze the dynamic response characteristics of the RC bridge piers under bi - directional seismic excitation, the bi - directional shaking table test of a RC bridge column was simulated by using the independent developed fiber beam - column numerical analysis platform FENAP, and the simulation result was compared with the experimental test results. Moreover, the time history response of bridge column under unidirectional seismic excitation was also analyzed by using the FENAP and its result was compared with bi - directional results to obtain the dynamic response difference between the two seismic loading conditions. Research conclusions： （ 1 ） The comparison result of numerical simulation by using FENAP with the experiment test of a RC bridge column under bi -directional shaking table test with FENAP and test shows that the FENAP platform can simulate the complicated coupled bi - axial bending moment behaviors of bridge column and predict the amplitude and appearance time of peak displacement on the top of bridge column effectively to get the comparatively accurate numerical results. （2） Furthermore, the comparison of the time history response of bridge column under unidirectional seismic excitation with bi -directional results shows that the analyzed response displacement of the bridge column subjected to bi- directional excitation is larger than that subjected to unidirectional excitation, while the response acceleration issmaller. （3） The bi - directional coupled effect of RC bridge pier can not overestimated and the response displacement be underestimated considered. （4） This research result is available for the seismic design railway and rail transit. be ignored, and the stiffness of column will be if only one directional seismic response is of large span continuous bridge of highway,