超高层结构地震位移及剪力响应峰值时滞效应研究

近年结构震害表明，超高层结构在远场地震动作用下出现了楼顶长时间大幅值晃动现象且时滞效应明显，其中大幅值晃动造成非结构构件破坏严重，现行设计方法对地震作用下超高层结构大变形的控制还有不足。因此，文中简要分析了结构响应峰值机理，对长周期结构进行了近场及远场地震波作用下的时程分析，研究了长周期结构响应峰值与地震波中和结构基本周期对应频率的脉冲族之间的相关性，讨论了结构弹塑性对超高层结构响应峰值时滞特征的影响。结果表明：超高层结构与地震波中对应频率的脉冲族产生类共振是引起结构大幅值晃动的主要原因，仅基于加速度反应谱拟合精度选出的地震波不能较好预测超高层结构的大变形；类共振出现在地震波衰减段时会引起时滞效应；结构弹塑性引起的刚度退化会影响结构响应峰值及其出现时刻。

Time-lag effect of peak displacement and shear force response of super high-rise building

The recent seismic damages of structures show that the top displacement response of super high-rise buildings in the far field excitation largely for a long time, and the time lag characteristic is obvious. Large amplitude sloshing causes serious damage to non-structural components, and there is insufficient of the current design method for large deformation control of super high-rise buildings. Thus, in this study, mechanism of peak response of structure is analysed briefly. Time history analysis is used for long period structure with near field and far field ground motions. The relevance between peak response of long period structure and the pulses with corresponding frequency is studied. How the peak response of super high-rise building is influenced by elasto-plastic behavior is discussed. The results indicate that large amplitude sloshing of super high-rise building is mainly caused by resonance with the pulses with the same period as building in the ground motion. The large deformation will not be forecasted by using time history obtained from acceleration response spectrum. Time lag is caused by resonance appearing in the attenuation section of earthquake ground motion. The amplitude and time of appearance of peak response of structure will be influenced by the stiffness degradation caused by elasto-plastic development.