Abstract In this study, nine laboratory tests were conducted to estimate the performance of earthquake-resistant structures, i.e., reduced beam section (RBS) connection, under a scenario in which the middle column is removed. Four types of joints were tested, namely, welded unreinforced flange – bolted web connection without RBS (WUF-B-NRBS), welded unreinforced flange – bolted web connection with RBS (WUF-B-RBS), welded unreinforced flange – welded web connection without RBS (WUF-W-NRBS), and welded unreinforced flange – welded web connection with RBS (WUF-B-RBS), to investigate the effect of RBS and different beam web connection methods. The experimental results involving the responses of general behavior, resistance mechanisms, failure modes, deformation shapes, and limit displacements are presented in detail. A performance comparison of different connection types indicated that the RBS connection exhibits the optimum performance against progressive collapse, and its practical rotational capacity is >1.9 and 2.7 times larger than that provided by Federal Emergency Management Agency (FEMA) 350 and Department of Defense (DOD) guidelines, respectively. Additionally, in the design of the RBS connection, the welded web connection joint exhibited good load-carrying capacity, whereas the bolted web connection joint performed poorly owing to early fracture near the bolt holes. Furthermore, the research parameters were extrapolated within and beyond the limits using ABAQUS. This demonstrated that by increasing the values of horizontal distance from the column flange to the beginning of the beam flange reduction, a, or the length of the beam flange reduction, b, is beneficial to structural load-carrying capacity and ductility. However increasing the value of depth of the beam flange reduction, c, has the opposite effect. Based on the comparison, the recommended design details of RBS connections are presented.

中文翻译：

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减少梁截面的钢力矩框架节点的渐进倒塌行为

摘要 在这项研究中，进行了9 次实验室试验，以评估抗震结构的性能，即在中柱被移除的情况下，减少梁截面（RBS）连接。测试了四种类型的接头，即焊接无筋法兰-无RBS螺栓腹板连接（WUF-B-NRBS），焊接无筋法兰-带RBS螺栓腹板连接（WUF-B-RBS），焊接无筋法兰-焊接腹板连接无 RBS (WUF-W-NRBS) 和焊接无加强法兰 - 带 RBS 的焊接腹板连接 (WUF-B-RBS)，以研究 RBS 和不同梁腹板连接方法的影响。详细介绍了涉及一般行为响应、阻力机制、失效模式、变形形状和极限位移的实验结果。不同连接类型的性能比较表明，RBS 连接表现出最佳的抗连续倒塌性能，其实际旋转能力比联邦紧急事务管理局 (FEMA) 350 和国防部 (DOD) 提供的大 1.9 倍和 2.7 倍) 指南。此外，在 RBS 连接的设计中，焊接腹板连接接头表现出良好的承载能力，而螺栓腹板连接接头由于螺栓孔附近的早期断裂而表现不佳。此外，研究参数是使用 ABAQUS 在限制范围内和超出范围外推的。这表明，通过增加从柱翼缘到梁翼缘减少开始处的水平距离值 a，或梁翼缘减少的长度，b、有利于结构的承载能力和延展性。然而，增加梁翼缘缩减深度 c 的值会产生相反的效果。在比较的基础上，提出了 RBS 连接的推荐设计细节。