基于IDA的混凝土斜拉桥桥塔非线性抗震需求分析

Nonlinear seismic demand analysis of concrete cable-stayed bridge tower using incremental dynamic analysis

由于缺乏对斜拉桥在地震作用下的损伤和破坏过程等基础研究,我国目前的桥梁抗震设计规范要求在偶遇地震作用下,斜拉桥的桥塔也需基本保持弹性。而近年来的研究表明桥塔在强震作用下有进入塑性的可能,且国外已建成的大跨度桥梁明确允许桥塔可以出现塑性。本文利用Open Sees有限元程序,对一典型中等跨度斜拉桥试验模型建立弹塑性有限元动力分析模型进行IDA分析,得出在顺、横桥向地震作用下桥塔的潜在塑性区域、塔顶位移及桥塔关键截面曲率IDA曲线,并利用以上结论指导混凝土斜拉桥模型的振动台试验加载方案设计,为发展斜拉桥非线性抗震理论提供必要的研究基础。

Due to lack of fundamental research on the study of damage process of cable stayed bridges under earthquake excitation,the bridge tower,as the main-load carrying capacity component of the bridge,is explicitly required to remain almost elastic even under the excitation of occasionally happened earthquake according to our current bridge seismic design codes. Recent studies show that the bridge tower may produce plastic failure under strong earthquake. Incremental dynamic analysis method is used in Open Sees to analyze the nonlinear seismic demand of the experimental model from a typical cable-stayed bridge. The potential plastic regions along the tower column,the IDA curves of the tower in regard to displacement and curvature demands under longitudinal and transverse earthquake inputs are obtained. The results are used to guide the shaking table test plan of the concrete cable-stayed model,which provides necessary research basis for the nonlinear seismic theory development of the cable-stayed bridge.