Importance of Isotropic Hardening in the Modeling of Buckling Restrained Braces

The seismic response of buckling restrained braces has often been modelled as elastic plastic with kinematic hardening or, even more simplistically, as elastic perfectly plastic. The use of these models has not raised particular criticism because of the lack of models able to represent the isotropic hardening with acceptable accuracy and reliability. In recent years, the effect of the isotropic hardening has been included in some more refined models of the seismic response of buckling restrained braces. One of these refined models is considered here in order to assess the effectiveness of some common models in which the effect of the isotropic hardening is not taken into account. The comparison is made on single-storey and multi-storey structures subjected to natural and artificial accelerograms.