高层建筑结构的扭转反应控制

高层建筑结构扭转反应控制是设计中的关键问题,但在《高层建筑混凝土结构技术规程》(JGJ3-2002)中还没有这方面的具体规定。因此,有必要对《高层建筑混凝土结构技术规程》中控制结构地震扭转效应的主要方法进行解说和讨论:限制结构在考虑偶然偏心的水平地震作用下,每个楼层的最大位移和最大层间位移与该层平均位移和平均层间位移的比值(位移比)以及结构以扭转为主的第一振型周期Tt与以平动为主的第一振型周期Tl之比值(周期比);分析位移比、周期比和偏心率之间的关系,并说明计算偶然偏心影响和控制位移比、周期比的必要性和可行性,以及在单塔楼工程设计中的应用;对于多塔楼高层建筑结构,提出了控制扭转效应的设计建议:对上部无刚性连接的多塔楼结构,宜将各塔楼及裙房由裙房顶板处切开分别计算各自周期比;对上部有刚性连接的多塔楼结构,应采用整体结构模型计算并验算整体扭转和平动的周期比。

Control of torsional response of tall building structures

The main methods to control earthquake-induced torsional response of tall buildings in the Technical Specification for Concrete Structures of Tall Building(JGJ3-2002)are expounded: restricting the ratio of the maximun displacement and drift of a storey to the corresponding averages(displacement ratio)computed under horizontal earthquake action including accidental eccentricity,and restricting the ratio of the first torsional vibration period to the first translational vibration period(period ratio).The relationships between the period ratio,the displacement ratio and the eccentricity of the structure are discussed,and the necessity and feasibility of computing the influence of the accidental eccentricity and controlling the period ratio and the displacement ratio of buildings as well as its application in the design of single-tower buildings are explained.Suggestions on the control of torsional response of multi-tower tall buildings(with or without rigid connections between towers),not yet prescribed in the Technical Specification for Concrete Structures of Tall Building(JGJ3-2002),are presented: for a multi-tower tall building without rigid connections between towers,it is recommended that the structure be partitioned from the top floor of the podium into parts and then check the period ratio of each part,whereas for a multi-tower tall building with rigid connections between towers,the period ratio should be checked for the global structure model.