Pressures on open canopy structures with parapets under wind loading

Pressure coefficients due to wind in open canopy structures with parapets, such as those commonly used in gas stations, are presented. Two independent methodologies were used to obtain pressure coefficients: wind tunnel testing and Computational Fluid Dynamic (CFD) modeling. The experiments were performed in a low velocity atmospheric boundary layer wind tunnel. The atmospheric boundary layer flow was simulated in the tunnel and a small scale model of a canopy made with aluminum plates was tested considering wind incidence at 0° (normal-to-the ridge direction) and 30°. Pressures were measured at a number of locations on the plate and the parapets. CFD models were investigated under steady state conditions using commercial software. The wind tunnel results for a canopy without parapets were found to be in agreement with results obtained by other authors. The CFD simulations were in good agreement with the wind tunnel results for canopies with parapets. The values of the net pressure coefficients on the main surface show downward pressures close to the windward zone, followed by suction at the center, and downward pressure on the leeward zone of the canopy. Differences with current recommendations for the design of canopies are highlighted.