基于数值子结构方法的防屈曲支撑高层钢结构地震动力分析

Seismic Response Analysis of Tall Steel Buildings Equipped with Buckling-restrained Braces Based on Numerical Substructure Method

近年来,高层建筑结构地震动力响应分析成为一个热点问题。防屈曲支撑构件(BRB)承载力高,延性与滞能性高,在强震作用下具有良好的耗能性能,正日益普及并用于高层建筑结构。高层建筑结构在地震作用下的失效往往是由部分关键构件损坏引起,而其他大部分构件仍处于弹性或小变形状态。采用常规的整体建模分析和Newton-Raphson迭代方法(NR)效率较低,而数值子结构方法将结构中进入强非线性状态或者发生严重损伤的构件进行隔离并精细化模拟,使大规模的非线性计算转化为主结构的线弹性分析和子结构的非线性分析,从而大大提高计算效率。本文基于数值子结构方法,对采用防屈曲支撑构件的高层钢框架结构进行地震响应分析,其中防屈曲支撑构件作为隔离子结构进行精细化建模分析,主结构部分采用线弹性分析。计算结果与采用钢支撑构件的高层结构进行对比,验证了数值子结构的高效性及防屈曲支撑构件的耗能性能。

Recent decades,seismic response analyses of tall buildings have received increasing attentions.The buckling-restrained brace(BRB),exhibitinghigh bearing capacity,ductility and great energy dissipation capacity under strong earthquake,has been widely used in tall building structures.The failure of tall building structures under earthquake is often caused by damages of some crucial components,while the other components might remain elastic or with small deformations.The seismic analysis has low efficiency when the conventional large scale nonlinear analysis based on Newton-Raphson(NR)methods are employed.The numerical substructure method(NSM)isolates the components that are damaged seriously or in highly nonlinear state,and simulates them using refined models.The large-scale nonlinear computation is divided into elastic analysis of the main structure and nonlinear analysis of substructures.Based on NSM,the paper performs seismic response analysis for tall steel building equipped with BRBs,where BRBs are isolated and simulated using refined models.The computational results are compared with those by conventional NR methods to verify the high efficiency of NSM,and with steel support components to study the dissipation capacity of BRBs.