This paper presents an experimental study on the flexural behaviours of new-generation direct-formed square and rectangular hollow sections (collectively referred to as RHS herein). A total of 22 beam specimens covering wide ranges of cross-sectional dimensions and nominal yield stresses (350 and 690 MPa) are tested. The results are compared to those from previously tested indirect-formed and hot-finished RHS to study the effect of different production processes. The effects of post-production hot-dip galvanizing on residual stresses and flexural behaviours are also studied. The applicability of slenderness limits and flexural design formulae in the current North American steel design standards are examined using the experimental data. The experimental results demonstrate that the existing flexural design rules are generally conservative for direct-formed RHS (ungalvanized and galvanized).

本文对新一代直接成形方形和矩形空心型材（本文统称为RHS）的弯曲行为进行了实验研究。总共测试了 22 个横梁试样，涵盖了广泛的横截面尺寸和标称屈服应力（350 和 690 MPa）。将结果与先前测试的间接成型和热加工 RHS 的结果进行比较，以研究不同生产工艺的影响。还研究了生产后热浸镀锌对残余应力和弯曲行为的影响。使用实验数据检验了当前北美钢材设计标准中细长限制和弯曲设计公式的适用性。