TOWARDS RELIABILITY-BASED LOCAL DESIGN WIND PRESSURES FOR SIMPLE RECTANGULARLY-SHAPED BUILDINGS

Standard assessment methods for local peak wind pressures are compared with a reliability-based assessment method. The latter combines second moment reliability (SMR) principles with wind pressure data from wind tunnel experiments and with the simplified Cook-Mayne approach to calculate local peak wind pressures on buildings with a consistent safety level. In an example, local peak wind pressures on the fronts and roofs of simple rectangularly-shaped buildings were calculated with different assessment approaches, where the mean and fluctuating wind pressures were measured in wind tunnel experiments. Differences in the results (in terms of peak pressure coefficients) are quantified and discussed and - by means of the results of the SMR approach - appropriate pressure gust factors, peak factors, and safety levels of the wind loads specified in the draft of the Eurocode ''Wind loads'' are calculated. It is shown, that local peak wind pressures in separated flow regions may be underestimated significantly if the pressures are assessed by means of the quasi-steady approach. Finally, maximum and minimum peak pressure coefficients from own wind tunnel experiments, which are required for the application of the SMR approach for design purposes, are discussed as a function of approach flow and building dimensions.