考虑桩土相互作用自锚式悬索桥地震响应分析

发布时间：2018-10-12 20:44

【摘要】：自锚式悬索桥的特点是将主缆锚固于梁的端部,省略了桥两端的锚碇。这样有利于在地质条件恶劣,不适合修建重力式锚碇的地方修建。我国是一个多地震的国家,地震所造成的损失占自然灾害损失的比例很高。本文所研究大桥位于盘锦地区,由于区域地质构造等原因,盘锦地区成为我国东北地区沿海软土的主要分布区。因此对在软土地基建设的桥梁进行地震分析具有很重要的工程意义。本文以一座主跨跨径为180m的自锚式悬索桥为研究对象,进行了结构的有限元计算分析。系统地研究了桩土相互作用和地震动参数等因素对桥梁结构动力特性及地震反应的影响。本文介绍了建立和求解动力方程的经典理论。采用Midas Civil建立了主跨180m的混凝土自锚式悬索桥盘锦纬一河大桥的有限元模型。有限元模型分为两种,一种采用“m法”建立桩土模型,另一种采用“p-y曲线法”建立桩土模型。对“m法”桩土相互作用模型的自振特性进行分析,得到了前100阶频率和相应振型。对比分析墩底固结模型和桩土相互作用模型自振特性的差异。对“m法”桩土模型进行反应谱分析,作为该桥地震响应的初步分析。介绍了选取地震波的基本方法,并通过调整实际地震记录的方法,生成了拟合规范反应谱的人工波,选择人工波作为输入。对“p-y曲线法”模型进行了地震响应时程分析,并对比了“m法”模型和“p-y曲线法”模型的时程分析结果。对比发现对于纵向周期比较长的自锚式悬索桥,两种计算模型的结果相差不大。再次本文对两种模型分别进行了罕遇地震作用下的时程分析,分析时程分析的结果两种模型的位移有差别,内力相差不大。
[Abstract]:Self-anchored suspension bridge is characterized by anchoring the main cable to the end of the beam and omitting the Anchorage at both ends of the bridge. This is conducive to the construction of gravity Anchorage where geological conditions are poor. China is a country with many earthquakes, and the damage caused by earthquakes accounts for a high proportion of natural disaster losses. The bridge studied in this paper is located in Panjin area. Due to regional geological structure, Panjin area has become the main distribution area of soft soil in Northeast China. Therefore, the seismic analysis of bridges on soft foundation is of great engineering significance. In this paper, a self-anchored suspension bridge with a main span of 180m is taken as the research object, and the finite element analysis of the structure is carried out. The effects of pile-soil interaction and seismic parameters on the dynamic characteristics and seismic response of bridge structures are systematically studied. In this paper, the classical theory of establishing and solving dynamic equations is introduced. The finite element model of Panjinwei-Yihe Bridge with main span of 180m is established by using Midas Civil. There are two kinds of finite element models, one is to establish pile-soil model by "m method", the other is to establish pile-soil model by "p-y curve method". The natural vibration characteristics of the "m method" pile-soil interaction model are analyzed, and the first 100 frequencies and corresponding modes are obtained. The difference of natural vibration between consolidation model and pile-soil interaction model is analyzed. The response spectrum analysis of "m method" pile-soil model is used as a preliminary analysis of the seismic response of the bridge. This paper introduces the basic method of selecting seismic wave, and by adjusting the actual seismic record, the artificial wave fitting the normal response spectrum is generated, and the artificial wave is selected as the input. The seismic response time history analysis of "p-y curve method" model is carried out, and the results of time history analysis of "m method" model and "p-y curve method" model are compared. It is found that there is no significant difference between the two models for self-anchored suspension bridges with long longitudinal periods. Thirdly, the time history analysis of the two models under rare earthquake is carried out respectively. The results of the analysis show that the displacement of the two models is different and the internal force is not different.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55;U448.25

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