长短周期地震波作用下钢框架结构的 响应特性对比分析

Comparative analysis of response characteristics of a steel frame structure under long-and short-period ground motions

作为一种特殊的地震动,长周期地震动对结构的危害已引起国内外学者的关注。选取10条KiK-net、K-NET台网中典型的长周期地震动,以及10条国内外的短周期地震动,对比分析两者时程特征和反应谱特征的差异。将所选长、短周期地震动输入钢框架结构模型;通过非线性时程分析,研究钢框架结构在长、短周期地震动作用下的响应差异。结果表明:短周期地震动的平均地面峰值加速度是长周期地震动的3.26倍,而平均地面峰值位移比长周期地震动低10.89%;短周期地震动作用下,钢框架结构顶点加速度响应平均值是长周期地震动的5.16倍,结构顶点位移响应平均值仅比长周期地震动多0.91%;长周期地震动作用下,钢框架结构层间位移角响应较大,结构底部受影响范围更广。对于长周期地震动隐患地区的高层钢框架结构,应对长、短周期震害分别进行考虑;对于中、长周期钢框架结构,建议选用峰值位移作为抗震分析指标。

As a special kind of ground motion,the damage of long-period ground motion to structures has attracted the attention of scholars at home and abroad.Ten typical long-period ground motions from KiK-net and K-NET networks and ten short-period ground motions at home and abroad were selected in this paper,and their differences in time-history characteristics and response spectrum characteristics were compared and analyzed.The selected ground motions were input into a steel frame structure model,and through a nonlinear time-history analysis,the response differences of the steel frame structure under long-and short-period ground motions were studied.The results show that the average peak ground acceleration of short-period ground motions is 3.26 times that of long-period ground motions,and the average peak ground displacement is 10.89%lower than that of long-period ground motion.Under short-period ground motion,the average value of acceleration response at the top of the steel frame structure is 5.16 times that under long-period ground motion,and the average value of displacement response at the top of the structure is only 0.91%more than that under long-period ground motion.Under the action of long-period ground motion,the response of story drift ratio of the structure is larger,and the bottom of the structure is affected more widely.For high-rise steel frame structures in areas with long-period seismic hazards,long-period and short-period seismic hazards should be considered respectively.For medium-and long-period steel frame structures,it is suggested that the peak displacement should be selected as the seismic analysis index.