The behaviour of brace members under cyclic loading

Theoretical and experimental studies have been made in this research to study the elastic and inelastic behaviour of steel brace members under cyclic axial tension and compression loading. Three steel members, made with 150 UC 30 sections, were tested. A refined physical theory model was used and the analytical results showed good agreement with the test results over several cycles. Three different overall slenderness ratios were tested: 40, 60 and 80. When higher axial displacements were reached, the peak values of the theoretical curves were less than the experimental curves in tension and greater than the experimental curves in compression. The differences were caused by the neglect in the model of the following: strain hardening, the reduction of tangent modulus with increased loading and the increase in the residual rotation angle of the plastic hinge.