Wind-induced torsional loads on tall buildings: Fid-Bau Portal

Wind-induced torsional loads on tall buildings

Lythe, G.R. / Surry, D.

AbstractThis paper primarily examines mean torsional wind loads on tall buildings using a large data base measured experimentally in wind tunnel tests; a brief examination of peak loads is also included. Although the mean load constitutes only a part of the total peak load required for design, it provides considerable insight into the aerodynamics of torsion, while improvement in its estimation also improves the estimation of the total peak load, using empirical gust factor methods. Comparisons between experimental results and the corresponding provisions of the 1985 National Building Code of Canada and Commentary (NBCC) indicate that, while the NBCC is a good estimator of mean shear loads, it significantly underestimates the mean torsional loads on tall buildings. The experimental data are further analysed to provide an improved estimation method for the mean torsion. This involves evaluating definitions of the torsion coefficient and classifying building shapes in order to decrease the variability of the associated coefficients. This process leads to some notion of those shapes susceptible to large torsional loads and the most important building parameters on which to base predictions.