几何非线性对大跨拱桥地震反应影响分析

Analysis on Influence of Geometric Nonlinearity on Seismic Response of Long-span Arch Bridge

该文以一座上承式钢桁拱桥为工程背景,用有限元软件MIDAS建立了全桥空间有限元模型。在分析了该桥自振特性的基础上,分别沿桥梁纵向、横向输入反应谱,分析了该桥的地震反应。以拱肋上弦的内力为研究对象,分析了恒载初始内力引起的几何非线性对该桥自振特性及地震反应的影响。研究结果表明恒载初内力引起的几何非线性不可忽略。

Taking a deck steel truss arch bridge as the engineering background, this paper sets up the three-dimensional finite element model of the whole bridge by using the finite element software MIDAS. Based on analysis of the natural vibration characteristics of the bridge, the response spectrum is inputted along the longitudinal and transverse directions respectively to analyze the seismic response of the bridge. As the study object of the internal force of upper chord of the arch rib, the paper analyzes the influence of geometric nonlinearity on the natural vibration characteristics and the seismic response of the bridge caused by the initial internal forces of dead load. The results show that the geometric nonlinearity caused by the initial internal forces of dead load can not be ignored.