于家堡贝壳形单层网壳不均匀雪荷载研究

Study on nonuniform snow load of seashell-shaped single-layer reticulated shell in Yujiapu

于家堡单层网壳体型较复杂,对雪荷载的选取应谨慎.基于CFD技术分别采用求解雪相控制方程和MIXTURE多相流模型对网壳表面风致雪漂进行数值模拟,得到屋盖表面雪沉积与侵蚀后形成的不均匀雪荷载.两种求解方法得到的雪荷载分布较一致,屋盖迎风面发生积雪侵蚀,随屋盖高度增加雪荷载呈抛物线形减小,至屋盖顶部天窗两侧雪侵蚀作用最大、雪压最小,天窗后部背风面处发生积雪沉积.对结构的静力和整体稳定性能进行分析,在不均匀雪荷载作用下天窗两侧部分杆件应力较均匀雪荷载时增大10%,结构极限承载力增大3%.

The shape of the single-layer reticulated shell in Yujiapu is complex,so we should be cautious about snow load.Based on the CFD technique,the non-uniform snow load was simulated after snow deposition and erosion happened on the roof by using the governing equation of snow method and the MIXTURE multiphase flow model method.The distributions of snow load were similar by using two solving methods.There was snow deposition in windward roof and the snow load decreased in a parabolic curve with the increase of height.Because of the intensive deposition,the snow load was minimum in two sides of the skylight and there was snow erosion in the leeside behind the skylight.Analysis on the static behavior and the global stability of the single-layer reticulated shell was conducted under the non-uniform snow load,and the results were compared with those under uniform snow load.It was shown that the stress of part members at the two sides of the skylight increased by 10%,and the ultimate bearing capacity increased by 3%.