长周期地震动作用下超高层建筑结构响应研究

Research on structural response of super high-rise buildings under long-period ground motion

超高层建筑结构自振周期相对较长,易受长周期地震动影响,是抗震设计时值得关注的问题。从PEER强震记录库中选取了Ⅱ类、Ⅲ类、Ⅳ类场地共410条工程中常用的强震记录,以一栋高250m、自振周期为6s的超高层建筑结构为例,从输入与输出两个层面对长周期地震动作用下的结构响应进行研究。输入层面,以规范设计反应谱为比较基准,通过分析地震动加速度反应谱,了解不同场地地震动的频谱特征;输出层面,以规范设计反应谱作用下的基底剪力为基准,通过分析超高层建筑结构在各类场地地震动作用下的基底剪力,获得不同场地地震动作用下的结构响应水平;同时,引用日本国土交通省公布的长周期设计地震动进行横向比较,通过弹塑性时程分析得到的不同时刻下结构塑性转角分布情况及发展规律,揭露长周期地震动作用下结构的响应特征与控制因素。

The super high-rise building structure has relatively long natural vibration period,so it is easily affected by long-period ground vibration. This is a problem worthy of attention in seismic design. The strong earthquake records commonly used in 410 projects of Class Ⅱ,Class Ⅲ and Class Ⅳ sites were selected from the PEER strong earthquake record database. A super high-rise building structure with a height of 250 m and a natural vibration period of 6 s was taken as an example. The structural response of the structure of the input and output levels under long-term ground motion was studied. At the input level,the response spectrum of the standardized design was used as the comparison benchmark,and the spectrum characteristics of the ground vibration in different sites were understood by analyzing the response spectrum of the ground vibration acceleration. At the output level,base shear force under the action of response spectrum of standard design was taken as the benchmark. Base shear force under the action of various ground motions of super high-rise building structures was analyzed to obtain the structural response levels under the action of ground motions of different sites. At the same time,by referring to the lateral comparison of long-period designed ground motion published by Japan Ministry of Land,Infrastructure,Transport and Tourism,the distribution and development law of structural plastic rotation angle at different time points were obtained through elastic-plastic time-history analysis,and the response characteristics and control factors of structures under the action of long-period ground motion were revealed.