Equivalence of plastic strength and hysteretic behavior of box and I-shaped shear links

Abstract

In seismic resilient structural systems like eccentrically braced frame and coupled shear wall system, a small beam-like segment known as the shear link is used as a replaceable structural fuse. Shear links dissipate seismic energy primarily by shear deformation. This study focuses on the numerical investigation of the shear capacities of short box-shaped and I-shaped links and the feasibility of interchangeability between them. For replacing links in post-disaster periods, this interchangeability between links of different shapes would allow designers to choose from a wider range of options leading to higher flexibility. Existing equations for the prediction of shear capacities were studied to find appropriate equations to be used for achieving equivalent hysteretic behavior by links of I-shaped and box-shaped sections. When shear capacities are estimated with the existing equations of the AISC code, the hysteretic behavior of a box-link differs from that of an I-link despite having the same shear capacity. These equations do not take into account the contribution of flanges in the resistance of shear forces. Instead, the alternative equations which include the full link depth are found to be more appropriate using which the same cyclic behavior can be achieved by either a box-link or an I-link (with the same shear capacity) in terms of hysteretic response, overstrength, and energy dissipation. An I-shaped link can be replaced with a box-shaped link of the same capacity and vice versa, when capacity prediction is done with the suggested equations.