基于多元模糊评定的桥梁综合地震易损性分析

摘要

Mainly,the classical seismic fragility of reinforced concrete bridges is calculated based on the parameter such as the cross-section curvature of the typical piers,for which the evolutionary process of the dynamic characteristics and the global performance are not sufficiently involved.The strategy which the comprehensive damage assessment is realized based on the fragility analysis of different parts of the bridge is proposed.It is assumed that the damage type and the degree have a substantiaconnection with the difference between the ideal elastic deformation energy and the actual elastic-plastic deformation energy,according to the concept of energy dissipation.The pier damage assessment method based on the differential value of energy dissipation is presented.The global multidimensional bridge fragility analysis method based on multi-order periods is suggested.With comprehensive evaluation method in fuzzy mathematics,combined with the damage analysis based on bearing displacement,the pier damage analysis based on energy and the global damage analysis based on periods,the multiple fuzzy fragility analysis method which embodies the damage states from detail to multi-level is established.A typical RC bridge is analyzed by multidimensional incremental dynamic analysis and seismic fragility analysis at all levels.The results show that the bridge seismic fragility analysis method based on multiple fuzzy evaluations can represent the dynamic characteristics and damage evolution process of the components and the total bridge,which has better accuracy and feasibility.%传统的钢筋混凝土桥梁地震易损性分析一般只根据主要桥墩的截面曲率等参数进行评估,对桥梁动力特性演变和整体性能考虑不充分.阐述了通过对桥梁不同部位进行易损性分析进而实现综合损伤评定的策略.从能量耗散角度论证损伤的形式和程度与结构理想弹性变形能和实际弹塑性变形能之间的差异相关,建立基于滞回耗能差的桥墩损伤评价模型.提出基于多阶周期的桥梁多维整体易损性分析方法.运用模糊数学中的综合评判方法,结合基于位移的支座损伤分析、基于能量的桥墩损伤分析和基于周期的整体损伤分析,建立了能够反映桥梁从细部到整体多层次损伤的多元模糊易损性分析方法.对算例桥梁进行多维增量动力分析和各级别的易损性分析,结果表明:基于多元模糊评定的桥梁地震易损性分析方法能准确细致地反映桥梁构件和整体的动力特性的损伤演变过程,具有较好的准确性和实用性.