Experimental Evaluation on LTB Strength of Steel Beams Externally Pre-stressed with Un-bonded Tendon Bar

A lateral-torsional buckling (LTB) experimental study has been firstly investigated for an externally pre-stressed (PS) steel beam with/without un-bonded central deviator. Analytical and numerical studies related to elastic LTB of the PS beam are abundant. However, an experimental study focusing on LTB behaviors of the PS steel beam is newly presented in this study. Six full-scale experimental specimens consisting of two usual steel beams without tendon bar, two PS steel beams under vertical loadings and two PS steel beams under increasing tendon force were tested. Load–strain/displacement behaviors of the specimens were obtained by measuring stains, lateral and vertical displacements. The numerical study of the geometric and material nonlinear behaviors of PS steel beams was evaluated based on the Riks method using ABAQUS. Finally, numerical and experimental results of load–strain/displacement behaviors of the usual and PS beams were investigated. The experimental and numerical results indicated that the LTB strength of steel beams could be greatly improved by prestressing system.