Improved computational methods for determining wind pressures and glass thickness in façades

Wind induced pressure is a major design consideration for determining the glass thickness and glass selection in façades. However, the effects of wind loading history on glass are largely neglected or grossly simplified. The use of computational techniques, such as Computational Fluid Dynamics (CFD), to tackle these issues is relatively untested in contrast to other fields of engineering where CFD is used as a routine design tool. This paper firstly addresses the use of boundary conditions which maintain the wind speed profile as it varies with height above the ground, a problem afflicting several CFD studies in the atmospheric boundary layer. It is then shown how CFD can be used together with wind tunnel studies to tackle difficult design situations. Subsequently, the effects of fluctuating wind loads on the structural strength of glass are assessed using transient, geometrically non-linear analyses and improved glass failure prediction models. Results are compared to those from current glass design standards where only peak gust pressures are considered, where it transpires that such a detailed analysis can give up to a 35% increase in efficiency.