超高层建筑共同分析中时变耦合对结构周期的影响

IMPACT OF TIME-DEPENDENT COUPLING ON STRUCTURAL PERIOD IN ANALYSIS OF STRUCTURE-SOIL INTERACTION OF SUPER HIGH-RISE BUILDING

超高层建筑共同作用系统的时变作用是相互耦合的,其计算是一个相互迭代,直至收敛的复杂过程。该问题主要涉及三部分内容,即地基基础沉降变形的时变性规律、上部结构的时变性规律和共同作用理论。另一方面,结构自振周期作为超高层建筑结构分析与设计的重要基本参数,其值不宜过短,也不宜过长,且需严格控制前三阶振型周期的比例。从地基沉降的时变性规律及上部结构的时变性规律出发,以时间切片的形式进行共同作用分析,综合考虑时变作用的耦合效应,采用共同作用时变效应分析方法,初步分析得到超高层建筑共同作用系统的时变性对结构周期的影响。分析结果表明：超高层建筑共同作用系统的时变性对结构前两阶振型的周期影响较大,与传统计算方法相比,周期会拉长1.25~1.4倍,这对于风、地震等水平荷载的影响较大,在工程实践中应引起重视。

The time-dependent actions of the structure-soil interaction（ SSI） system are coupled to each other,and its calculation is a complex process of iteration,until convergence. This issue mainly involves three parts,namely,the time-dependent law of foundation settlement,the time-dependent law of superstructure and the interaction theory.In addition,structural natural vibration period is an important basic parameter of structural analysis and design for super high-rise buildings. Structural natural vibration period should not be too short,neither too long,and the period proportion of first three orders for vibration modes should be strictly controlled. By considering the time-dependent laws of foundation settlement and superstructure,the interaction of super high-rise buildings and foundation was analyzed through using time-slicing approach. Comprehensively taking account of the coupling effects of timedependent actions,this paper discussed the impact on structural period in the integrated SSI system of super high-rise buildings. The analysis results showed that the impact on structural periods of first two orders for vibration modes caused by the time-dependent actions was great. Compared with the traditional method,the structural periods was increased by 1. 25 to 1. 4 times,which has a great influence on the wind and seismic loads,to which much attention should be paid in the engineering practices.