考虑桩土作用效应的钢筋混凝土桥墩易损性分析

Fragility analysis of reinforced concrete bridge piers considering the effect of pile-soil interaction

为研究桩土之间相互作用对桥墩易损性的影响,本文基于OpenSees数值分析平台,建立了二维桥墩的墩底固结模型和桩-土-桥墩模型。以位移延性比为损伤指标,地面峰值加速度PGA为地震动强度指标,对桥墩体系进行增量动力分析,通过对比2种桥墩模型在各损伤水平下的易损性曲线,得出桩土作用对桥墩易损性的影响,同时也研究了配筋率对桥墩地震易损性的影响。结果表明:考虑了桩土作用效应后的桥墩发生损伤破坏的概率比不考虑桩土作用效应时大,在进行桥墩易损性分析时,桩土作用需加以考虑;在考虑桩土作用效应的情况下,随着墩身配筋率的增加,桥墩抗易损性能力有所提高。

To study the influence of the interaction between piles and soil on the fragility of bridge piers, based on the OpenSees finite element software analysis platform, a two-dimensional pier bottom consolidation model and a pile-soil-pier model are established. In this paper, the displacement ductility ratio is selected as the damage index, and the ground peak acceleration PGA is the ground motion intensity index. Incremental dynamic analysis is performed on the bridge pier system. By comparing the fragility curves of the two pier models at various damage levels, the influence of pile-soil action and the reinforcement ratio on the fragility of the pier are obtained. The research concludes that the damage probability of the pier after considering the effect of pile-soil is bigger than when the effect of pile-soil is not considered. The effect of pile-soil needs to be considered when analyzing the fragility of the pier;in the case of considering the effect of pile-soil interaction, with the increase of pier body reinforcement ratio, the piers antisexual fragility has increased.