下击暴流作用下单层球面网壳结构易损性分析

Fragility Analysis of Single-Layer Reticulated Shell Structures Subjected to Downbursts

大跨空间结构风敏感性突出,极易遭受下击暴流影响。针对目前缺乏大跨空间结构抗下击暴流性能评估方法的问题,对下击暴流作用下单层球面网壳结构的易损性进行了研究,提出了针对下击暴流荷载的结构易损性分析方法。综合考虑下击暴流荷载的随机性与结构参数的不确定性,采用随机增量动力分析法求解不同荷载强度下的结构响应。结合易损性分析理论和二次回归分析,计算得到结构易损性函数,并进一步绘制易损性曲线,实现结构的抗下击暴流性能评估。研究结果表明:通过随机增量动力分析法和易损性分析的结合,能够对结构的抗下击暴流性能进行有效评估。在下击暴流这种极端风荷载作用下,单层球面网壳结构可能达到倒塌防止性态点(CP),而达到整体失稳性态点(GI)的概率则相对较小。

Long-span spatial structures are highly sensitive to wind loads,and are vulnerable to downbursts.In view of the lack of performance evaluation method for downburst-resistance of such structures,fragility of the single-layer spherical reticulated shell subjected to downbursts was studied,and a structural fragility analysis method for downburst loads was proposed.Considering the randomness of downburst loads and the uncertainty of structural parameters,the random incremental dynamic analysis(IDA)method was used to solve the structural response under different load intensity.Combined with the fragility analysis theory and quadratic regression analysis,the fragility function of the structure was calculated,and the fragility curves were further drawn to evaluate the downburstresistance performance of the structure.The results showed that the combination of stochastic IDA method and fragility analysis could effectively evaluate the structural downburst-resistance performance.With the action of downbursts,the single-layer spherical reticulated shell might reach the CP performance point,while the probability of reaching the GI performance point was relatively small.