Physical Theory Hysteretic Model for Steel Braces

Abstract

This paper presents a simple yet efficient physical theory model that can be used to simulate the inelastic cyclic axial force–axial deformation and axial force–transverse deformation relationships of steel braces. The model consists of a brace idealized as a pin ended member with a plastic hinge located at its midlength. Input parameters of the model are based only on the properties of the brace. The model combines analytical formulations based on the nonlinear behavior of the brace with some semiempirical normalized formulas developed on the basis of a study of available experimental data. The model realistically accounts for growth effect and degradation of buckling capacity due to Baushinger effects and residual kink present within the brace and it is broadly applicable to steel braces with various section types and slenderness ratios. It is observed that the analytically obtained axial force versus axial displacement as well as axial force versus transverse displacement hysteresis loops compare reasonably well with the experimental ones.