框筒结构简化非线性单元模型

框筒结构因能够利用结构的整个宽度抵抗侧向荷载引起的倾覆弯矩在高层建筑中得到了广泛的采用。按照三维空间框架结构对框筒结构进行非线性分析需要很大的计算量。将结构作为整体考虑能够减少计算量,但由于梁柱构件的柔性,结构中出现的剪力滞效应使得分析变得复杂。该文通过采用等效连续化方法得到的剪力滞系数,在Timoshenko 梁理论及多垂直杆单元模型的基础上,提出一个框筒结构简化非线性单元模型。该模型能够考虑腹板和翼缘板的剪力滞效应,计算量大为减少,可用在初步设计对框筒结构的非线性性能进行快速的评估。

A SIMPLIFIED NONLINEAR ELEMENT MODEL OF FRAME-TUBE STRUCTURES

Frame-tube structures are widely adopted in tall buildings since they can utilize the whole width of the structures to resist the overturning moment caused by lateral loading.A large amount of calculation is needed,if the structures are treated as three-dimensional space-frame structures in nonlinear analysis.Taking the structures as a whole to be analyzed will reduce the amount of calculation,but the problem will become complicated because of the occurrence of shear lag which is caused by the flexural and shear flexibilities of the frame members.In this paper,the shear lag coefficients are calculated through equivalent membranes analogy.Based on Timoshenko beam theory and multi-vertical-line-element model,a simplified nonlinear element model is proposed.In this model,shear lags in web and flange are considered.The amount of calculation is greatly reduced and the model is suitable for quick evaluation of frame-tube structures in nonlinear analysis during the preliminary design stage.