Study on wind loads on flat roof of canopied low-rise building and aerodynamic strategy for wind load reduction

The distributions of mean wind pressure and extreme wind pressure on flat roof of rectangular and circular canopy structure models were investigated in a boundary layer wind tunnel.The mechanism of wind-induced damages of the canopy roof was analyzed.Generally,the cladding design of those canopy structures is dominated by suction wind pressures.The results show that the maximum mean negative pressure coefficients on the rectangular and circular canopy reach-1.83 and-0.97,respectively,and the maximum peak negative pressure coefficients are found to be-5.41and-3.11 which are much more than the values proposed by the gust factor approach of GB 50009.This indicates that the gust factor approach is not suitable for the calculation of roof pressure on the envelope structures.According to the characteristics of wind loads on the canopy,several aerodynamic strategies to reduce the maximum suction wind pressure at wind sensitive locations on the canopy by venting the leading edges and chamfering the roof edge were recommended.The experimental results show that the suggested strategies can make a reduction of 25% ~35% wind load on the roof's sensitive locations.Based on the analysis results,the local shape factors for the rectangular and circular canopy structures were recommended.