弦支穹顶结构动力分析

基于局部分析法并且在以预应力作为自平衡的初始内力情况下对弦支穹顶结构的动力特性进行了初步分析。局部分析法采用将索杆体系和上部单层网壳分开的思想，使弦支穹顶结构的初始预应力分布的确定得到简化。随着上部网壳结构的整体刚度的降低，预应力对体系的自振特性的影响逐渐增大。该体系的低阶振型大多为竖向振动振型。由时程分析的结果可见竖向常遇地震作用下索杆内力上下变化的幅度并不大（不超过7％）。竖向常遇地震作用下结构响应由内环、中环到外环逐渐减弱。常遇水平地震作用下体系索杆内力上下变化的幅度更小。相比竖向常遇地震作用下的索杆内力的变化要小的多。同时，常遇水平或竖向地震作用下线性和非线性时程分析差别不大。

Dynamic analysis of suspend-dome

Based on the local analysis method,a preliminary dynamic property & response analysis of suspend-dome is carried out by taking account of the pre-stress as self-equilibrated initial internal force.The basic theory and steps of local analysis method are presented.On the basis of the idea of cutting off the lower cable-bar system from the upper single-layer reticulated shell,the determination of the distribution of the self-equilibrated initial internal force of suspend-dome is simplified.Comprehensive dynamic properties and time history analysis are conducted.While decreasing the stiffness of the upper reticulated structure the effect of pre-stress on the natural frequencies of the whole structure becomes larger.Most of the low-order vibration modes are vertical ones.The fluctuation of the internal force in the cables and bars is not very significant under vertical frequently meeting earthquake(not over 7%) and much smaller under horizontal frequently meeting earthquake.At the same time there is no significant difference between the linear and nonlinear time history analysis.