考虑看台干扰的大悬挑钢结构飘篷风荷载分析

Analysis on wind load of large cantilevered roof considering grandstand interference

针对某大跨度飘篷钢结构,为保证合理的风荷载取值,进行了考虑看台干扰效应的风荷载分析。构建了混合型网格模型,壁面为贴体O-Grid。基于CFX的多重分区全隐式耦合算法,利用非线性k-ε的EARSM湍流模型模拟了建筑风场,分析了静风压系数、流场特征、不同风向角下风压变化规律。研究表明:迎风时看台的阻滞作用会导致飘篷风吸力增长近1倍;背风时,看台的撞击扩散导致飘篷上下表面风压反向抵消,风压减小。结果转换为设计可用的体型系数,将其和相关规范进行了对比,吻合性较好,为工程设计提供了参考。

A large cantilevered steel structure roof was studied by means of numerical simulation where the wind load was a serious concern.The interference effect caused by grandstand on wind field was taken into account in order to obtain reasonable results.A mixed grid model with the O-Grid wall was developed.The multigrid method based on the full implicit coupling scheme of CFX was employed using nonlinear k-ε EARSM turbulence model.The static wind pressure coefficients,the flow field characteristics and the variation of wind pressure of different wind directions were analyzed.The outcomes indicate that the blockade caused by grandstand under windward condition can increase wind suction by nearly one time.Under leeward condition,the impingement and the turbulent diffusion can weaken the total wind load on the upper and lower roof surface.The results were converted into shape coefficients for design,which were in good agreement with the relevant codes.Thus,a reference can be provided in practice.