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静力Pushover分析是应用能力谱法进行抗震分析的重要一步,也是研究结构非线性受力特征的重要方法之一。本文采用Pushover分析方法,同时考虑地基土与桩构件的非线性,研究了群桩基础桥墩的侧向加载模式与非线性受力特征。研究结果表明:(1)侧向加载模式不同,获得的能力曲线不同。均匀分布和墩顶集中力加载模式分别反映了结构能力曲线的上、下限,一阶振型和SRSS分布介于两者之间。建议群桩基础的Pushover分析应采用SRSS加载模式。(2)墩高小于20 m时,高速铁路简支箱梁桥的水平惯性力主要集中在墩顶及承台处。(3)受拉侧单桩初始屈服后,群桩基础的承载能力还可继续增加,但横桥向多排桩(4排桩)群桩基础增加更明显。横桥向多排桩群桩基础的位移延性系数高于纵向两排桩的情况。
Static Pushover analysis is an important step in applying seismic profiling to seismic profiling and is also one of the most important methods to study the nonlinear characteristics of structures. In this paper, the Pushover method is used to analyze the lateral loading modes and the nonlinear force characteristics of pile foundation piers considering the nonlinearity of foundation soil and pile components. The results show that: (1) The lateral loading modes are different and the ability curves obtained are different. The uniform distribution and the concentrated load at the top of the pier respectively reflect the upper and lower bounds of the structural capacity curve, with the first-order mode and the SRSS distribution in between. Pushover analysis of proposed pile foundation should use SRSS loading mode. (2) When the pier height is less than 20 m, the horizontal inertial force of the simple-supported box girder bridge of high-speed railway mainly concentrates at the pier top and the platform. (3) The bearing capacity of pile foundation can continue to increase after the initial yielding of the tensioned pile, but the pile foundation of multi-row pile (4-row pile) in transverse bridge increases more obviously. The displacement ductility coefficient of multi-row pile group pile foundation is higher than that of two rows of pile in longitudinal direction.