近断层脉冲型地震动作用下大跨斜拉桥地震响应分析

发布时间：2018-06-20 20:57

本文选题：近断层地震动 + 破裂前方效应　；参考：《振动与冲击》2017年21期

【摘要】：为研究近断层脉冲效应和土-结构相互作用(SSI效应)对大跨斜拉桥地震响应的影响规律,以苏通大桥斜拉桥为研究对象,采用系统化的集总参数模型表征地基土的动力特性,建立了考虑SSI效应的结构动力数值计算模型,计算分析了破裂前方效应脉冲、滑冲效应脉冲和无脉冲三组近断层地震动作用下结构的地震响应。计算结果表明:相对于塔底固结模型,SSI效应降低了斜拉桥自振频率,并改变了高阶振型的产生次序;近断层地震动作用下,SSI效应可增大主塔位移响应,对其内力有削弱作用,并可降低纵桥向激励时主梁的位移和内力响应,但横桥向激励时,脉冲效应地震动作用下SSI效应明显增大了主梁的响应;脉冲效应地震动引起斜拉桥地震响应明显高于无脉冲地震动,滑冲效应主要影响纵桥向激励时主塔响应以及纵桥向(或横桥向)激励下主梁响应,破裂前方效应对横桥向激励下主塔响应影响更加显著。研究成果可为大跨斜拉桥在近断层地震动作用下的抗震设计提供借鉴。
[Abstract]:In order to study the influence of near-fault pulse effect and soil-structure interaction (SSI) effect on seismic response of long-span cable-stayed bridge, a systematic lumped parameter model is used to characterize the dynamic characteristics of foundation soil, taking the cable-stayed bridge of Sutong Bridge as the research object. A numerical model of structural dynamics considering SSI effect is established. The seismic responses of three groups of near-fault seismic action are calculated and analyzed. The results show that compared with the tower bottom consolidation model, the SSI effect reduces the natural frequency of cable-stayed bridge and changes the generation order of higher-order vibration modes, and the lower SSI effect can increase the displacement response of the main tower and weaken the internal force. It can reduce the displacement and internal force response of the main beam under longitudinal excitation, but the SSI effect increases the response of the main beam obviously under the excitation of the transverse bridge. The seismic response of cable-stayed bridge caused by ground motion with pulse effect is obviously higher than that without pulse ground motion. The slip impact effect mainly affects the main tower response of longitudinal bridge and the main beam response under longitudinal (or transverse) excitation. The effect of fracture front on the response of main tower under transverse excitation is more significant. The results can be used as reference for seismic design of long span cable-stayed bridges under near-fault seismic action.
【作者单位】：东南大学混凝土及预应力混凝土结构教育部重点实验室;东南大学国家预应力工程技术研究中心;上海市市政规划设计研究院;
【基金】：国家自然科学基金(51378110) 江苏省“六大人才高峰”第十一批(JZ-007) 江苏省研究生科研创新计划(KYLX15_0086)
【分类号】：U442.55;U448.27

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