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.

首先针对带有/不带有无粘结中心偏向器的外部预应力（PS）钢梁进行了横向扭转屈曲（LTB）实验研究。与 PS 梁的弹性 LTB 相关的分析和数值研究非常丰富。然而，本研究新提出了一项针对 PS 钢梁 LTB 行为的实验研究。测试了六个全尺寸实验试件，包括两根无筋杆的普通钢梁、两根竖向荷载下的PS钢梁和两根增加筋力的PS钢梁。通过测量污点、横向和垂直位移来获得样本的负载-应变/位移行为。使用 ABAQUS 基于 Riks 方法对 PS 钢梁的几何和材料非线性行为进行了数值研究。最后，研究了普通梁和 PS 梁的载荷-应变/位移行为的数值和实验结果。试验和数值结果表明，预应力系统可以大大提高钢梁的LTB强度。