土-桩-结构相互作用对大跨度CFST拱桥地震反应的影响

Influences of soil-pile-structure interaction on seismic response of long span CFST arch bridge

以湖南益阳茅草街大桥为研究对象,采用J.Penzien质量-弹簧体系模拟桩基础与地基,基于ANSYS软件建立了该桥大跨度中承式钢管混凝土(CFST)系杆拱桥的三维有限元模型.以此为基础对茅草街大桥的地震反应进行了空间非线性时程分析,研究了不同地震动输入下土-桩-结构相互作用对该桥地震响应的影响.研究结果表明,土-桩-结构相互作用对大跨度CFST拱桥地震反应的影响易受地震动输入方式等因素的影响,非常复杂,但是当基础刚度得到保证后,采用拱脚固结模式进行抗震分析是可行的.

The Maocaojie Bridge is taken as an example, which is a concrete-filled steel tube (CFST) arch bridge with a main span of 368 m. Based on the software ANSYS, a spatial finite element model for the bridge is established and the soil-pile-structure interaction is simulated using modified J. Penzien model. Then a 3-dimensional nonlinear time history analysis for the bridge is investigated. Effects of soil-pile-structure interaction on the seismic response of the bridge are particularly studied under various earthquake simulations. Results show that effects of soil-pile-structure interaction are closely related to the way of earthquake simulations. The arch foot fixed model can be used in seismic resistant analysis on condition that the rigidity of the pile foundation is ensured.