ANALYTICAL APPROACH TO WIND VELOCITY GUST FACTORS

An analytical expression is derived for the factors (called wind velocity gust factors) by which the mean wind speed is scaled to obtain a maximum gust speed. The analysis is based on the assumptions of the horizontal wind velocity spectrum being of the von Karman form, and the probability distribution of the horizontal wind velocity being of gaussian form. The wind velocity gust factors are obtained as functions of the structural size and hence can be used to obtain an appropriate design wind speed for any given structure. The analytical expression for these factors depends on a number of dimensionless parameters from which conclusions are drawn regarding wind tunnel modelling of wind effects on structures. Measurements related to the extremes of a filtered linearized velocity signal from a hot-wire anemometer in a wind tunnel simulation of the atmospheric boundary layer are described. These show good agreement with the predictions of the analysis. © 1979.