Nonstationary near-ground wind characteristics and wind-induced pressures on the roof of a low-rise building during a typhoon

Wind fields in the surface layer during typhoons usually have strong nonstationary features, which cause damage to low-rise buildings, especially their roofs. It is thus required to establish accurate models of typhoon-generated near-surface wind fields and assess typhoon effects on lowrise buildings. In this paper, a framework of extracting time-varying mean component and determining time-varying fluctuating component of nonstationary signals is established, which is applied to investigate the on-site measured near-ground nonstationary wind velocities and wind induced pressures on the roof of a typical low-rise building during a typhoon. It is observed that near-ground wind characteristic parameters (including turbulence intensities, gust factors, peak factors and turbulence integral length scales, wind spectra) and wind pressure coefficients on the roof obtained by the nonstationary analytical approach are more reasonable than those determined by the conventional stationary analytical approach. Besides, the evolutionary power spectral density is used to examine time-frequency spectra of wind velocities and wind pressures. This comparative study based on the nonstationary and stationary analysis approaches aims to further the understanding of the nonstationary surface layer wind characteristics and wind pressures on typical low-rise buildings for reduction of windstorm damages to residential buildings in typhoon-prone regions.