考虑高阶振型影响的时程分析加权调整选波方法  

Weighted scaling and selecting method of ground motions in time-history analysis considering influence of higher modes

作　　者：张锐[1,2] 王东升 陈笑宇[4] 李宏男 Zhang Rui;Wang Dongsheng;Chen Xiaoyu;Li Hongnan(Dalian University o f Technology, Dalian 116024, China;Dalian Jiaotong University, Dalian 116028, China;Hebei University of Technology, Tianjin 300401, China;Dalian Maritime University, Dalian 116026, China)

机构地区：[1]大连理工大学,辽宁大连116024 [2]大连交通大学,辽宁大连116028 [3]河北工业大学,天津300401 [4]大连海事大学,辽宁大连116026

出　　处：《土木工程学报》2019年第9期53-68,99,共17页China Civil Engineering Journal

基　　金：国家自然科学基金（51778206)

摘　　要：针对长周期结构抗震时程分析输入地震波选择问题,提出一种在较宽的周期范围内实现反应谱与目标谱一致性匹配的地震波选择及调整方法。在匹配误差指标(SSE)和地震波幅值调整系数(SF)计算中采用了加权形式的最小二乘法,引入由归一化振型参与系数确定的结构前几阶振型的权重系数,以充分考虑高阶振型对结构地震反应的不同贡献。以美国SAC Steel Project提出的20层抗弯钢框架结构为实例,以该计划提出的代表3种超越概率(即50年超越概率50%、10%和2%)的各组地震波平均反应谱作为目标谱,以这3组地震波(每组10个台站双向记录,即20条波)时程分析得到的结构最大层间位移角均值为各超越概率下的目标反应;以简单地震信息初选的小型地震波数据库(共40条波)作为备选波,选用3条、7条和10条3种地震波数量及不同排序原则的6种分组方式,将加权调整选波方法与不考虑权重的等权调整方法所得各分组地震波反应谱,以及结构时程分析结果进行比较。研究表明,加权与等权方法对估计结构反应(如最大层间位移角)均值具有相同的准确性,但在降低结构反应离散性方面,加权方法具有较大优势。此外,若任意选择地震波组进行时程分析时,采用加权方法也可在一定程度上降低结构反应计算结果的离散性。For the selection and scaling of ground motions in time-history analysis of long-period structures, a wide-band matching and weighted scaling method was proposed. In calculating the matching errors(SSE) and scaling factors(SF), the weighted least-squares method was applied. The weight coefficients of the first several modes of structures were introduced and determined by normalized modal participation factors, so that different contributions of higher modes to structural dynamic responses can be fully taken into account. The 20-story steel moment resisting frame structure designed for the American SAC Steel Project was used as an actual example. The average response spectra of the three ground motion sets developed in the project representing three exceedance probabilities(that is, 50%, 10%, and 2% probabilities of being exceeded in 50 years, respectively) were used as the target spectra. And the average values of the structural maximum inter-story drift angles calculated from the three ground motion sets(two-way records from 10 stations for each set, that is, 20 records) were taken as the benchmark seismic responses of each exceedance probability. The small-size database of seismic waves(total 40 records) established by simple geophysical parameters was used for selection and scaling. Six groups with 3 or 7 or 10 records and in different sequence were selected. The selection and scaling method with weighting was compared with that without weighting for predicting the mean structural response. The weighted and unweighted scaling methods have almost the same accuracies for estimating the mean structural responses(such as the maximum inter-story drift angle), but the weighted scaling method is superior to the unweighted method in reducing the variability of the structural responses. Moreover, if the ground motions are selected randomly, the weighted scaling method can also reduce the variability of the structural responses to some extent.

关 键 词：时程分析 地震波选择 高阶振型影响 加权调整方法 抗弯钢框架 

分 类 号：TU311.3[建筑科学—结构工程] P315.9[天文地球—地震学]