Abstract Steel frame structures with ordinary weld connections often suffer from brittle fractures; to mitigate this issue, measures have been taken to integrate plastic hinges and improve the ductility of the steel connections. A new reduced beam section (RBS) connection, consisting of radius cuts in the beam flanges and circular openings in the beam webs, is proposed to allow for more ductile connections. RBS connections may increase structural deflection and crack width in the steel frame structure under large deformations. Therefore, it is extremely important to consider the bearing capacity and progressive collapse resistance of steel frame structures with RBS connections. In this study, nine different specimens with double-span frames were constructed and tested under a central column removal scenario: one without an RBS (RBS0), one with flange reductions (RBS1), and seven with web and flange reductions (RBS2). The mechanical behaviours of the different specimens were determined, including their failure modes, vertical force-deformation responses, and contribution of catenary action to resist progressive collapse. The results indicated that the RBS0 specimen with brittle failure did not effectively resist progressive collapse. RBS1 exhibited superior ductility and resistance compared to RBS0; however, its resistance to progressive collapse after cracking required further improvement. RBS2 with web openings formed an arch structure to dissipate energy through continuous deformations. Further, two important factors in RBS2 that influenced its mechanical properties were the diameter and the distance of the web opening, which were related to the development of arching and catenary action.

中文翻译：

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减少梁截面的梁柱连接抗连续倒塌试验研究

摘要 普通焊缝连接的钢框架结构经常发生脆性断裂；为了缓解这个问题，已采取措施整合塑料铰链并提高钢连接的延展性。提出了一种新的减少梁截面 (RBS) 连接，包括梁翼缘中的半径切口和梁腹板上的圆形开口，以允许更多的延展性连接。RBS 连接可能会增加钢框架结构在大变形下的结构挠度和裂缝宽度。因此，考虑RBS连接的钢框架结构的承载力和抗连续倒塌性能极为重要。在这项研究中，九个不同的双跨框架试件在中心柱移除场景下构建和测试：一个没有 RBS (RBS0)，一个带法兰缩减量 (RBS1)，七个带有腹板和法兰缩减量 (RBS2)。确定了不同试样的力学行为，包括它们的破坏模式、垂直力-变形响应以及悬链线作用对抵抗渐进式坍塌的贡献。结果表明，具有脆性破坏的 RBS0 试样不能有效地抵抗渐进式坍塌。与 RBS0 相比，RBS1 表现出优异的延展性和抵抗力；然而，它对开裂后连续坍塌的抵抗力需要进一步提高。带有腹板开口的 RBS2 形成了一个拱形结构，通过连续变形来耗散能量。此外，RBS2 中影响其机械性能的两个重要因素是网孔的直径和距离，