Inelastic moment-rotation response of 690 MPa grade steel I-section girders

Abstract

Recent specifications have adopted moment-rotation relationships for I-section girders with yield strengths up to 485 MPa to realize adequate and reliable ductility and the development of strength significantly greater than the yield moment. In this study, experiments were performed in order to verify the inelastic moment strength and examine an equation that appropriately expresses the inelastic moment-rotation response of high-strength steel I-section girders in the negative moment region. Three test girder specimens were fabricated and tested to their ultimate bending strengths up to failure. The test results were compared with the maximum strengths predicted for I-girders by finite element analysis and the nominal moment-plastic rotation curve in the specifications. A sufficiently redundant shakedown behavior was revealed by the comparison, which experimentally confirmed the adequacy of the current design equation for the moment-plastic rotation curve to 690 MPa grade steel I-girders. Based on the experimental results, conclusions were drawn regarding the inelastic moment-rotation behavior.