下承式钢管混凝土拱桥地震响应分析

发布时间：2018-05-01 15:31

本文选题：钢管混凝土拱桥 + Pushover　；参考：《兰州交通大学》2017年硕士论文

【摘要】：钢管混凝土拱桥以其科学合理的受力特性,新颖优美的结构形式而受到了桥梁科技工作者的青睐。由于钢管混凝土拱桥受力比较复杂,其抗震问题一直是钢管混凝土拱桥有待深入探讨的问题。本文将以南河特大桥为工程背景,具体工作有以下几个方面:(1)利用弹性节点支撑模拟桩土效应,计算南河特大桥模拟桩土效应时所需的土层刚度;对南河特大桥建立考虑桩土效应的空间模型,求解该桥的固有频率和振型。(2)依据选波的原则,调整所选的三条地震波后,采用纵向输入和三维地震输入的动态时程分析方法,计算南河特大桥地震作用下拱肋控制截面的位移和内力,并与反应谱结果进行对比,将其结果以折线图的形式呈现出来。(3)重新划分桩单元,计算土弹簧的刚度值,建立该种模拟方式下的空间模型,分别计算出纵向输入和三维地震输入作用下的响应,对比分析两种方案的结果,表明该种简化方式是满足精度要求的。同时考虑地震输入角度、阻尼比以及桩底模拟方式等几个因素对桥梁地震反应的影响。(4)采用pushover方法,考虑加速度常量加载和归一化模态加载两种加载模式对于性能点求解的影响。绘制出桥墩X方向、Y方向上的pushover曲线,通过公式把pushover曲线转换需求谱曲线,同时计算两方向上的性能点。利用现行抗震规范求解纵横两方向上的容许位移,从而对南河特大桥桥墩的抗震性能做出评判。
[Abstract]:Concrete-filled steel tubular arch bridge is favored by bridge science and technology workers for its scientific and reasonable stress characteristics and novel and beautiful structural form. Due to the complexity of concrete filled steel tube arch bridge, the seismic problem of concrete filled steel tube arch bridge needs to be deeply discussed. In this paper, taking Nanhe Bridge as the engineering background, the concrete work includes the following aspects: 1) using elastic node support to simulate pile-soil effect, calculate the soil stiffness required when Nanhe Bridge simulates pile-soil effect; A spatial model considering pile-soil effect is established for Nanhe large bridge. The natural frequency and mode shape of the bridge are solved. According to the principle of wave selection, the three selected seismic waves are adjusted, and the dynamic time-history analysis method of longitudinal input and three-dimensional seismic input is adopted. The displacement and internal force of arch rib control section under earthquake action of Nanhe Bridge are calculated, and the results are compared with the results of response spectrum. The results are presented in the form of broken line diagram. (3) the pile element is redivided and the stiffness of soil spring is calculated. The spatial model under this simulation mode is established and the responses under longitudinal input and three-dimensional seismic input are calculated respectively. The results of the two schemes are compared and analyzed. It is shown that the simplified method meets the precision requirements. At the same time, the influence of several factors, such as seismic input angle, damping ratio and simulation method of pile bottom, on bridge seismic response is considered. (4) pushover method is used. The effects of acceleration constant loading and normalized mode loading on the solution of performance point are considered. The pushover curve in X direction and Y direction of bridge pier is drawn. The pushover curve is converted into demand spectrum curve by formula, and the performance points in both directions are calculated at the same time. The allowable displacement in both directions is calculated by using the current seismic code, and the seismic performance of the pier of Nanhe super bridge is evaluated.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55;U448.22

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