基于IDA方法的悬索桥地震破坏机理分析中地震输入合理选择  

Reasonable selection of earthquake inputs in seismic damage analysis of suspension bridges based on IDA method

作　　者：聂利英[1] 陈佳彬[1] 刘群[1] 李建中[2] 

机构地区：[1]河海大学,江苏南京210098 [2]同济大学,上海200092

出　　处：《土木工程学报》2015年第6期64-72,共9页China Civil Engineering Journal

基　　金：土木工程防灾国家重点实验室开放课题(SLDRCE-MB-02)

摘　　要：以非线性时程分析为基础的IDA方法可作为展现以桥塔为主要目标的悬索桥地震破坏模式研究的有力工具。地震动输入的不确定性是时程分析结果离散性大的决定性因素。因此首先需为以IDA为工具的悬索桥地震破坏模式研究选择恰当的地震动记录以及IM指标。基于地震动记录选波研究现状,明确恰当的选波数量、选波方法及采用的工具和数据库。以悬索桥为对象,根据悬索桥桥塔高阶振动和非线性软化效应的地震响应特点,讨论谱匹配参数设置。以PGMD开放程序为工具,采用两级选波方法在PEER-NGA数据库中选出40条地震动记录,通过对比Sa(T1,5%)和PGA调幅下桥塔地震响应离散性,最终选定18条地震动记录以及PGA为合理的IM指标,并通过悬索桥IDA分析曲线验证选波的合理性。研究详细展示了如何利用现有开放强震数据库,以IDA为工具进行某一特定结构抗震性能研究时,选择合理地震动记录及IM指标的方法及过程,也可为悬索桥地震破坏模式的研究提供基础。Incremental Dynamic Analysis( IDA) is an effective method for collapse behavior investigation of a suspension bridge based on non-linear time history analysis. Results in structural dynamic response( especially in the non-linear range) vary significantly due to the random nature of ground motions. Thus,preliminary work of this investigation is to find out a suit of appropriate ground motion records and an efficient intensity measure( IM). Based on the state-of-the-art research of earthquake ground motion record selection,appropriate record number for IDA,selection method and Database are determined firstly. Then the key selection parameters of period range for matching spectrum are discussed in detail considering the contribution of higher modes and period elongation caused by inelastic response. Forty initial records are selected from the PEER-NGA database by PGMD web application. Subsequently,by analyzing the dispersion of the seismic responses with Sa( T1,5%) and PGA as IM respectively,18 final refined selection records and PGA as efficient IM are determined,and their rationality is verified by IDA analysis. The selection of reasonable earthquake records as well as efficient IM when using IDA to investigate the seismic performance of a specific structure is elaborated. The research results can provide reference for the investigation of collapse behavior of suspension bridges.

关 键 词：IDA 地震动记录选波 IM指标 离散性分析 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U442.55[交通运输工程—道路与铁道工程]