Pressure coefficient distributions for the design of hypar membrane roof and canopy structures

Abstract

Membrane structures are used in the built environment as roof or canopy and must therefore be designed to resist the external conditions. Nonetheless, the topologies of membrane structures are not covered by existing wind load standards and relevant wind load distributions for the basic shapes of these structures are almost not available. To have a realistic analysis of the wind loading, wind tunnel tests can be performed for each design. However, due to the lack of resources or time, for many projects the wind analysis will be based on rough approximations by relying on conventional shapes in the Eurocodes, with applying very high safety factors or designing unsafe structures as risk. Therefore, this paper presents a study of the orientation and curvature dependency of the wind load distributions over hypar roof and canopy structures. This study is performed with a numerical wind tunnel, using CFD with Reynolds averaged Navier Stokes equations. The outcomes are summarised in pressure coefficient distribution plots for most important wind orientations for hypar roofs and canopies with different curvature. The presented pressure coefficient distributions can be used in line with the Eurocode to derive more relevant wind load estimations for hypar membrane structures. These wind load estimations will give the engineer information about the average response of these structures under wind loading and will facilitate more reliable wind design of membrane structures.