Mean wind loads on porous canopy roofs

Mean overall lift and drag forces on a range of canopy or open roof forms with varying porosities are presented. In general, lift forces decrease while for low roof pitches (α<15°) drag forces increase as porosity is increased in the range 0–23%. Resolution of these forces into equivalent net roof pressures reveals that wind load may be transferred from the leeward to the windward areas, leading to potential overloading of the supporting structure. Mean and fluctuating pressure measurements were undertaken to confirm the inferred pressure distributions on the roofs.