Gust effect factors for windward walls of rigid buildings with various aspect ratios

Abstract

This paper examines the aerodynamic mechanisms associated with gust effect factors for windward walls of rigid buildings. The analysis utilizes two experimental databases with 58 rectangular-plan building models. Statistical characteristics of windward wall pressures, such as skewness, kurtosis, and peak factors, are examined along with parameters related to the wind spectra and the aerodynamic admittance. It was found that the statistical characteristics depend primarily on the aspect ratio defined as the ratio of height to breadth, H/B. The results also show that the area-averaged windward wall pressures present Gaussian distributions when the aspect ratio exceeds 6. Moreover, the measured aerodynamic admittance function for area-averaged windward wall pressures, referenced to the mid-height velocity spectra, matches reasonably well with Vickery’s model. The energy content of the wind-induced pressure on windward walls are influenced by horseshoe vortex of low-rise buildings with H/B ​< ​1. The pressure fluctuations at windward wall locations near the edge conjunct with side walls are also influenced by the vortex shedding over side walls for high-rise buildings. The gust effect factor model adopted in ASCE 7–16 is able to accurately assess the gust effect factors for rigid high-rise buildings, but is inaccurate for low-rise buildings, primarily because of the role of the horseshoe vortices.