冲刷作用对大跨度自锚式悬索桥地震响应的影响

发布时间：2018-07-04 16:14

本文选题：地震响应 + 大跨径自锚式悬索桥　；参考：《沈阳建筑大学学报(自然科学版)》2015年05期

【摘要】：目的研究冲刷作用对大跨度自锚式悬索桥桥塔地震响应的影响,为此类桥梁冲刷条件下抗震设计提供参考.方法采用考虑几何非线性的全桥有限元模型,并应用m法模拟土对桩基的约束刚度,分析不同基础冲刷深度条件对基础刚度和桥梁整体动力特性,以及对高耸桥塔地震响应的影响.结果冲刷效应通过减小土对桩基的约束,使桥塔基础刚度明显减小,但桥梁竖向和纵向基频不受影响,高阶振型及其地震效应的变化控制了结构的某些地震响应;不同冲刷深度下,桥塔关键截面-塔底截面纵桥向内力会出现明显峰值,而塔顶位移及横桥向内力效应呈现不同的规律.结论对于大跨度自锚式悬索桥高耸桥塔结构,最不利地震荷载效应并不完全发生在冲刷深度最大时,抗震设计需要考虑地震下多目标效应的多级冲刷的精细化处理方法.
[Abstract]:Aim to study the effect of scour on the seismic response of long span self-anchored suspension bridge tower, and to provide a reference for seismic design of this kind of bridge under scour conditions. Methods the finite element model of the whole bridge considering geometric nonlinearity was adopted, and the constrained stiffness of soil to pile foundation was simulated by m method, and the stiffness of foundation and the dynamic characteristics of bridge were analyzed under different conditions of erosion depth of foundation. And the influence on the seismic response of the towering tower. Results by reducing the soil constraint on the pile foundation, the foundation stiffness of the bridge tower is obviously reduced, but the vertical and longitudinal fundamental frequencies of the bridge are not affected, and some seismic responses of the structure are controlled by the changes of the high-order modes and their seismic effects. Under different scour depth, there is obvious peak value of the longitudinal bridge force between the key cross-section and the bottom section of the bridge, while the displacement of the tower top and the internal force effect of the transverse bridge show different laws. Conclusion for the towering tower structure of long-span self-anchored suspension bridge, the most unfavorable seismic load effect does not completely occur in the maximum scour depth, and the seismic design needs to consider the multi-objective effect under earthquake to deal with the multi-stage scour finely.
【作者单位】：同济大学桥梁工程系;
【基金】：国家自然科学基金项目(51378383)
【分类号】：U442.55;U442.55

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