Performance-based wind design of tall buildings

Abstract

A probabilistic procedure for the performance-based design of tall buildings subject to wind actions is illustrated. The central objective of the procedure is the assessment of the adequacy of the structure through the probabilistic description of a set of decision variables (DVs). Each DV is a measurable attribute that represents a specific structural performance (no collapse, occupant safety, accessibility, full functionality, admissible displacements or accelerations, etc.). The structural risk is conventionally measured by the probability of exceeding a relevant value of the corresponding DV; the probability is evaluated by taking into account the Aeolian hazard at the site, the calculated structural response and damage and the correlation between the attained damage and the relevant DV. The procedure is applied to an example case: the assessment of the comfort requirement for a 74-storey building. Probabilistic calculations are carried out in frequency domain, but the parameters of the wind velocity field are calibrated on the basis of the time histories of the forces that have been obtained by experimental tests on a 1:500 scale rigid model of the building. The occupant comfort is related to motion perception and measured by the probability of not exceeding threshold values of the across-wind acceleration at the top of the building.