Peak Inelastic Displacement of Bilinear Systems in Support of Performance-Based Wind Design

Abstract

A fundamental notion in building engineering is the equal displacement rule, which posits that the peak inelastic displacement of a system subjected to a ground motion excitation is approximately equal to the displacement of the same system responding elastically. The purpose of this study is to determine if the equal displacement rule can additionally be applied to wind excitations. To achieve this purpose, bilinear single-degree-of-freedom systems were subjected to B-spline wavelet excitations, Fejér–Korovkin wavelet excitations, and wind excitations derived from wind tunnel tests. The results showed the equal displacement rule generally held for excitations with neutral polarity. The frequency content of the excitation had a significant effect on the response because it shifted the location of the displacement-controlled region of the response spectrum. Duration had a mild effect for excitations with neutral polarity. The effect of stiffness and strength degradation due to gravity loads on the response was more pronounced for short-period structures. For regularly shaped buildings subjected to wind forces, the findings suggest that the equal displacement rule applies in the cross-wind direction however not in the along-wind direction.