多点输入下大跨空间网格结构的拟静力位移影响因素分析

Effects of some parameters on pseudo-static displacement of space lattice structures under multiple support excitations

根据对不同跨度(60,80,100,120m)和结构形式(柱壳、球壳、网架)的大跨空间网格结构所进行的多点输入竖向和水平地震作用的时程计算结果,总结了拟静力位移随结构跨度、视波速和自振周期的变化规律,分析了不同结构形式拟静力影响程度不同的原因.分析结果表明拟静力位移响应较大的点主要集中于支座附近,且拟静力位移的影响从支座向跨中不断减弱;视波速对拟静力位移的影响甚微;结构自振周期和结构跨度对不同类型的空间网格结构的拟静力位移影响存在差异,但变化的幅值不大;地震波的传播方向对拟静力位移分布规律没有影响.

On the basis of the time history response of space lattice structures under multiple support excitations, the rules of pseudo-static displacement development are summarized herein, which are related to structural span, apparent velocity and natural free-vibration period of structure. Moreover,the effect of structural form on pseudo-static displacement is analyzed, by which the conclusions obtained in the paper can be interpreted. The joints whose pseudo-static displacement are dominant in response are located near the support, and the effect of pseudo-static displacement on structure is decreased from edge to middle position. Apparent velocity has little effect on pseudo-static displacement, while structural span and natural free-vibration period of structure have various effects which meet the need of structural form. The directions of seismic wave have no effect on pseudostatic dis-placement。