大跨空间桁架与混凝土支承结构体系协同工作分析

Analysis of cooperative effect of large span space truss with supporting concrete structure

上部大跨空间桁架结构与下部混凝土支承结构体系是常见的大跨结构形式。对于此类混合结构体系,现阶段的工程设计大多将上部大跨钢结构与下部混凝土支承结构分开进行设计计算。在对上部大跨钢结构单独进行计算分析时,边界条件采用简化的支座模型以模拟下部混凝土支承结构。然而这样的处理方式无法准确反映结构的实际受力情况,因此,通过整体建模进行此类混合结构的计算分析以揭示其静动力特性非常有必要。本文通过对比武汉银河汇主入口屋盖工程的单独计算结果与考虑下部混凝土支承结构协同工作的整体计算结果,得出考虑协同工作与不考虑协同工作两者在周期振型、支座反力、杆件内力、单元应力和构件位移等方面均存在差异,采用简化的固定支座或铰支座模型不能完全模拟下部混凝土支承结构对上部大跨钢结构的约束作用。论证了对于混合结构体系考虑协同工作的必要性,并对两者产生差异的原因进行了分析。

Large span space truss with supporting concrete frame is the common form of large span structures. At present,the usual method of analysis for this kind of hybrid structures is to take apart the upper steel structure and the supporting concrete structure for separate calculation. Simplified supporting conditions are used to simulate supporting concrete structure when the upper steel structure is analyzed. However,this method may not be able to reflect the real situation of the structure. Therefore,it is necessary to conduct the integral analysis for hybrid structures. The calculation results between stand-alone steel roof and the whole structure with supporting concrete frame of Wuhan Yinhehui Center project are compared in this paper. The differences in natural periods,vibration modes,support reaction forces,element inner forces,element stresses and component displacements are obtained. It shows that it is not accurate enough to use simplified fixed or hinge joint supports to simulate supporting concrete structure. The conclusion demonstrates the importance of cooperative effect for hybrid structures. And the reasons why the differences generate are analyzed.