The current paper investigates the role of initial imperfections at web-flange junction on the lateral torsional buckling behavior of pultruded fiber reinforced polymeric beams. This study is based on experimental and numerical results, which are developed in two main steps: perfect beams and beams with initial imperfections at the web-flange junction. In the first step, small-scale tests are carried out to calculate the mechanical properties of the composite section. Perfect and imperfect pultruded I- and C- shaped beams are subjected to full-scale experimental tests under an applied four-point bending load with a total lengths varying from 1500 to 3000 mm, and 2500–3500 mm for the I- and C-beams, respectively. The end conditions of all beams studied are simply supported. Perfect beams are tested to investigate their dominant failure mode, as well as the impact of lateral bracing on the failure modes. While, imperfect beams are tested to determine the effect of initial imperfections on the lateral-torsional buckling capacity and failure mechanisms.

本文研究了腹板-法兰连接处初始缺陷对拉挤纤维增强聚合物梁的横向扭转屈曲行为的影响。这项研究基于实验和数值结果，它们是通过两个主要步骤开发的：完美的梁和腹板-法兰交界处具有初始缺陷的梁。第一步，进行小规模测试以计算复合材料截面的机械性能。完美和不完美的拉挤成型的I型和C型梁在施加的四点弯曲载荷下进行了全面的实验测试，其总长度从1500到3000 mm不等，I和C型的总长度为2500–3500 mm梁。所研究的所有梁的最终条件都得到了简单支持。测试完美光束以研究其主要破坏模式，以及横向支撑对破坏模式的影响。同时，对不完美的梁进行测试以确定初始缺陷对横向扭转屈曲能力和破坏机理的影响。