On the seismic performance of yielding asymmetric multistorey buildings: A review and a case study

The history of the static seismic provisions for asymmetric structures, mainly as manifested in the evolution of the code-specified design eccentricity ed formula, i.e. ed = αie ± βb, is briefly outlined. It is shown that although the ed formulas were originally developed for the linear range, these formulas, in particular that of the UBC, lead, trough judicious distribution of overstrength, to similar levels of ductility demand as predicted for similar but symmetric structures. These studies are mostly confined to single storey models. Yet, recent, recent research suggests that single storey results may be applicable, albeit with minor modifications, to regular asymmetric shear buildings. In the case study an attempt is made to compare the dynamic response of a 7-storey R/C wall-frame building with results of pushover analyses including those with mass locations based on the ed formulas in order to test their predictive power.