基于稳定等效的覆雪屋盖静力风荷载计算方法

摘要

To avoid the dynamic instability of roofs in snowstorms,a method of stability-based equivalent static wind loads was presented.Snowdrifts on roofs are firstly simulated by the computational fluid dynamics (CFD) method.The state of dynamic instability of the snowy roof is determined by the Budiansky-Roth criterion.Then,the computational theory of stability-based equivalent static wind loads is constructed by referring to the principle of the gust loading factor method.Finally,the theory is applied to a real double-layer cylindrical reticulated shell.The results show that the snowy roof takes on evident instability under strong winds,and would become dynamically unstable when the wind velocity is 1.0 times the basic wind velocity.The critical wind velocity for wind-induced dynamic instability of snowy roofs,which is 35.8 m/s for the shell,can be obtained by static stability analysis using the proposed method.%为了避免屋盖结构在暴风雪中发生动力失稳,建立了基于稳定等效的静力风荷载计算方法.采用计算流体动力学方法模拟了屋面积雪漂移现象；根据Budiansky-Roth准则判定了覆雪屋盖的动力稳定性；借鉴阵风荷载因子法构建了基于稳定等效的静力风荷载计算方法；最后,对实际双层柱面网壳进行了动力稳定性设计.研究结果表明,强风下覆雪屋盖出现较为明显的失稳阶段,当风速为设计基准风速的1.0倍时,屋盖发生动力失稳,静力失稳计算可得临界风速为35.8 m/s,该结果可作为该屋盖设计的动力失稳临界风速.