Analytical downburst wind load calculation methods: Review and full-scale validation

Abstract

Downburst outflow winds are identified by their distinct transient nature with a surge in wind speed succeeded by a subsequent decrease. It has been known that the classical frequency domain approach for atmospheric boundary layer winds in which the wind speed fluctuation is considered stationary and Gaussian might not be applicable for downburst winds. Researchers have proposed time-domain, frequency-domain, and time–frequency-domain approaches to advance analytical downburst wind load calculation methods. In this study, two approaches, namely the thunderstorm response spectrum (TRS) and the generalized gust response factor (G-GFF), methods are thoroughly discussed, compared, and validated with full-scale structural monitoring data. The two methods were selected because of the completeness of their framework, applicability for multiple degrees of freedom systems, and most importantly their feasibility for engineering application and future codification. The discussion and comparison covered a wide set of structures and the sources of uncertainties in both methods were highlighted indicating points of improvement. The validation using full-scale monitoring data during two case studies of downburst events showed that the two methods predicted the peak top displacement with a range of 12%–41% increase. • The Thunderstorm Response Spectrum and the Generalized Gust Response Factor methods are studied. • The two methods are discussed and systematically compared covering a wind set of structures. • Full-scale monitoring data of a structure registered during two downburst case studies is used for verification.

Topics & Concepts