Cyclic Response of Steel Braces

Abstract

A model for inelastic response analysis of braced steel structures is presented. This model achieves realism and efficiency by combining analytical formultions with formulas developed on the basis of a study of experimental data. A brace is idealized as a pin‐ended member with a plastic hinge located at its midspan. Analytical expressions for the axial force versus axial deformation behavior of the brace are derived on the basis of the classical beamcolumn equation and a plastic flow hypothesis for the plastic hinge. Several empirical behavioral characteristics are incorporated to achieve better representation of observed cyclic inelastic behavior. The model is implemented in a computationally efficient manner so as to be suitable for studying the dynamic response of relatively large structural systems. Verification of the new model is performed on the basis of a quasi‐static analysis of an individual strut and dynamic response analyses of a braced steel frame. The model is able to accurately simulate the cyclic inelastic behavior of steel braces and appears to be reliable and applicable to dynamic analyses of braced frame structures.