计入弹性基础效应的钢筋混凝土桥梁结构塑性倒塌分析

将钢筋混凝土桥墩墩顶在单位水平力作用下的变位，分解为桥墩的弹性弯曲变位、基础转动产生的变位及基础平动产生的变位之和，从而建立了一种计入弹性基础效应和弹性支座效应的钢筋混凝土梁桥横桥向抗震评估的塑性倒塌分析模型，给出了等效弹性地震荷栽计算方法、钢筋混凝土梁桥塑性倒塌分析计算公式及独柱墩在地震力作用下的双线性刚度实用分析方法。算例表明，计入弹性基础效应和弹性支座效应后，钢筋混凝土粱桥的最终抗震能力与结构延性明显下降。

Plastic collapse mechanism of seismic assessment for existing RC bridges with flexible foundation and bearing pads

The deformations of reinforcement concrete bridge piers were divided into three parts, elastic deformation caused by a unit horizontal force at the top of the bridge piers, the rotation deformation and foundation translation deformation. A plastic collapse mechanism analysis mode of seismic assessment for existing reinforcement concrete bridges with flexible foundation and bearing pads was developed. Its analysis procedures and formulas with respect to the effect of elastic ground and elastic bearings were newly derived, and the practical analysis approaches of bilinear stiffness of bridge piers were given. An improved analysis method of seismic assessment for reinforcement concrete bridges was derived from equivalent elastic response acceleration at the limit state by considering the variety of the structural displacement ductility capacity caused by flexible foundation and bearing pads. An example shows that the structural displacement ductility capacity of reinforcement concrete bridges and seismic capacity are apparently reduced owing to considering flexible foundation and bearing pads.8 tabs, 5 figs, 8 refs.