Wind loads on curved roofs

Curved roofed buildings are increasingly used in the modern built environment because they offer aerodynamically efficient shapes and provide architects and designers with an alternative to regular rectangular building forms. However, there is little information available on the wind loads on these roof forms. The Eurocode for wind actions (EN1991-1-4) includes pressure coefficients for a limited range of aspect ratio cylindrical roofs from measurements in low-turbulence conditions but only for wind blowing normal to the eaves. There is some concern regarding the reliability of these data, consequently EN1991-1-4 allows National Choice (National Determined Parameter) for wind loads on these roofs. This paper describes a series of parametric wind tunnel studies undertaken at BRE to measure wind pressures on a wide range of curved roof models in a properly scaled atmospheric boundary layer simulation and gives an alternative to the EN1991-1-4 recommended procedure.