近断层地震下层间隔震结构楼层反应谱

Research on Floor Response Spectrum of Storey Seismic Isolation Structure Sunder Near-fault Earthquake

近断层地震动富含长周期、大峰值的速度脉冲的特性,而目前对近断层地震动作用下非结构构件动力响应的研究较少.本文对一个5层钢框架结构进行非隔震与层间隔震振动台试验和ABAQUS有限元模拟,研究表明:(1)结构设置隔震层,能明显降低屋面楼层加速度反应βac谱谱值,谱值随着隔震层的升高而增大;同时增大了屋面楼层位移反应βd谱谱值,随着隔震层设置位置的升高,谱值大幅度减小.(2)与抗震和隔震结构的自振周期有相近脉冲周期的地震波能明显增大屋面楼层位移反应βd谱和屋面楼层加速度反应βac谱谱值;非隔震与隔震结构屋面楼层加速度反应βac谱和楼层位移反应βd谱主要峰值周期与主体结构基本自振周期接近.(3)近断层地震波与结构周期比值越近,断层距越小,有脉冲作用,屋面楼层加速度反应βac谱和楼层位移反应βd谱谱值越大.

Near-fault ground motions are rich in velocity pulses with long periods and large peak values,and there are few studies on the influence of near-fault ground motions on the dynamic response of non-structural members. The shaking table test and ABAQUS finite element simulation of a five-story steel frame structure with non-isolation and story isolation were carried out. The results show that:( 1) the structure with isolation layer can significantly reduce the acceleration response beta spectrum of the roof floor,which increases with the increase of the isolation layer;at the same time,it increases the displacement response beta of the roof floor.With the increase of the location of isolation layer,the spectral value decreases greatly.( 2) the seismic waves with similar impulse periods to the natural vibration periods of aseismic and isolation structures can significantly increase the beta spectrum of floor displacement response and acceleration response of the roof;the main peak period of the beta spectrum of floor response of non-isolation and isolation structures is close to the basic natural vibration period of the main structure.( 3) the closer the ratio of near-fault seismic wave to structural period is,the smaller the fault distance is,and the impulsive effect is. The greater the beta spectrum of floor acceleration response and floor displacement response is.