大跨度桥梁抗震分析中的整体有限元法及其应用

    Integral FEM for Seismic Response Analysis of Long-span Arch Bridge and its Application

    • 摘要: 为了研究高烈度区抗震设计中桩土相互作用对大跨度桥梁结构地震反应影响,本文采用基于虚拟人工边界的整体有限元法来考虑桩土相互作用,并与无桩模型以及我国公路桥梁抗震规范中推荐采用的m法模型得到的结果进行对比分析,在建模分析中采取多尺度建模方法,开展了桩土相互作用对大跨度拱桥地震响应的影响规律以及关键构件局部受力和变形特征研究。结果表明:桩土相互作用将增大计算模型拱座和关键节点应力和位移响应,建议m法应用于同类型大型桥梁抗震分析时,应考虑合理安全系数以保证强震作用下大跨度拱桥的抗震安全性。

       

      Abstract: In the seismic design of long-span bridges in high intensity areas, the interaction between pile and soil can not be overlooked. The m method is recommended to consider the pile-soil interaction in Code for seismic design of highway bridges in China, which is suitable for small deformation linear elastic soil, but its accuracy and applicability in the face of strong earthquakes need to be discussed further. In this paper, the integral finite element method based on virtual artificial boundary is used to consider the pile-soil interaction, and the results obtained from m method model and pile-free model are compared and analyzed. In order to reflect the stress and deformation of key parts of components, and take into account the calculation efficiency, this paper adopts the multi-scale modeling method to study the influence law of pile-soil interaction on long-span arch bridge seismic response and the local stress and deformation characteristics of key components in the modeling process. The results show that the pile-soil interaction will increase the stress and displacement response of arch seat and key nodes. It is re commended that when m method is applied to the seismic analysis of large bridges, a reasonable safety factor should be considered to ensure the seismic safety of long-span arch bridges under strong earthquakes.

       

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