长周期地震动对超高层结构抗震性能的影响

Seismic Performance of Super High-Rise Structures Under Long-Periods Ground Motions

历次大地震中,长周期结构在长周期地震动作用下响应剧烈。本文着重对超高层建筑进行长周期地震激励下的抗震性能分析,选取了远场类谐和地震动、近断层向前方向性地震动和近断层滑冲型地震动3类典型长周期地震动记录各3条,为进行比较,同时选了3条普通地震动作为输入样本,采用ABAQUS有限元软件对一54层超高层结构分别进行多遇地震下的弹性时程分析和罕遇地震下的弹塑性时程分析,并将4类地震动输入下的结构响应特征进行对比研究。由结果可知:长周期地震动作用下结构的位移、位移角及损伤均大于普通地震动的响应,尤其是低频成分更丰富的远场类谐和地震动;长周期地震动输入下结构的最大层间位移角接近甚至超出限值。因此,长周期地震动对超高层结构抗震性能的影响不可忽视。

All previous earthquakes show that the long-period structure responds violently under long-term ground motion. This paper focuses on the seismic analysis of super high-rise buildings under long-period seismic excitation. Three types of typical long-period ground motion records are selected for the far-field harmonic ground motions,near-fault forward-directivity ground motions and nearfault fault fling-step ground motions. For the comparison,three ordinary earthquakes are selected as the input samples. The finite element software ABAQUS is used to build a 54-story super-high-rise structure and the elastic time history analysis under frequent earthquake,and the elasto-plastic time history analysis under rare earthquake are carried out respectively. The structural response characteristics of four kinds of earthquake excitation are compared. It can be seen from the results that the displacement,interstory drift ratios and damage of the structure under long-period ground motions are all greater than those of ordinary ground motions,especially the far-field harmonic ground motions of the low-frequency component. The maximum interstory drift ratios of the long-period ground motion input are close to code limited value or even beyond the limited value. It can be seen that the effect of long-period ground motion on the seismic performance of super-high-rise structures can not be neglected.