Mode shape correction for wind-induced dynamic responses of tall buildings using time-domain computation and wind tunnel tests

Abstract

The high-frequency force-balance (HFFB) technique is a common and effective wind tunnel testing method for the assessment of wind-induced dynamic responses of a tall building. The technique works in the frequency domain with the inherent assumption of ideal mode shapes so that the base moments can approximate the generalized forces. In this study, time histories of wind forces at several levels of a tall building model are obtained in the wind tunnel with a multi-channel pressure scanning system. This enables the building responses to be computed directly in the time domain for buildings with non-ideal mode shapes. Mode shape correction factors for the HFFB technique are thus obtained for the dynamic deflections and moments. The dependence of the mode shape correction factors on mode shapes and vertical distributions of wind excitation and building masses is investigated systematically. These correction factors are found to agree generally with the predictions proposed in previous studies but some differences are noted on the commonly assumed profiles of wind excitation and correction for torsion.