高层混合结构中楼盖刚度对结构受力性能的影响分析

通过楼板将两种变形特性完全不同的结构体系连接而成混合结构,在受力性能上与框架结构、筒体结构既具有一定的联系,又有本质的区别。本文以一30层外部为钢框架、内部为混凝土核心筒组成的混合结构为例,采用通用有限元程序SAP2000分别计算了钢框架结构、混凝土筒体结构及混合结构,比较了三种结构体系的受力性能;通过调整楼板型式和板厚,探讨了楼板刚度对混合结构受力性能的影响。结果表明,采用混合结构使得结构变形、内力沿高度方向趋于均匀,受力性能得以改善;采用梁板体系能有效地减轻剪力滞后;随着楼板刚度的增加,结构高阶自振周期增大,侧移减少,层间剪力、楼层弯矩及总钢框架承担剪力、弯矩增加;而钢框架承担总剪力、弯矩百分比减少。

Effect of Floor Rigidity on Behaviors of Hybrid Structures

There are some essential differences and some relations on behaviors among frame structures, tube structures and hybrid structures which are mix of the former tow. In this paper, behaviors of a 30-story hybrid structure with outer steel frames and inner concrete-tube under horizontal load were analysed and compared with steel frame structure and concrete tube structure with the commercial FEM program,SAP2000. By changing the type and thickness of floor, the effect of floor rigidity on behaviors of hybrid structure was discussed. It showed that the structural deformation and inner force became uniform along height direction, and the structural behavioris improved with using bybrid structural system. Shear lag could be alleviated by using beam-plate structure. With the floor rigidity increasing, periods of higher mode of vibration increase, structural lateral displacements decrease, and floor shear, floor moment and inner force borne by total steel frames increases.However, the total shear shared by steel frames bearing increases and the total moment shared by steel frames decreases.