The beam-column connections are known as a fundamental component in steel moment-resisting frames. The present investigation studies the progressive collapse behavior of four various welded types of beam-column connections including, welded unreinforced flange-welded web moment (WUF-W), reduced beam section (RBS), welded flange plate (WFP), and welded flange-weld web connection with internal diaphragms (I-W). The nonlinear analysis with suitable finite element modeling has been generated to assess the connection's performance under a column removal scenario. The load–displacement curves, fracture modes, Von-Mises stresses, and other comparable theoretical results were described. The results are verified with existing experimental data. The results of the analyses showed that the studied models' overall failure occurs in the beam-column connection regions in the large rotation under the catenary action mode. The plastic strain accumulation occurred around the access hole, and the failure was initiated from these areas. Each of the investigated connections showed sufficient strength under column removal scenario. WFP connections demonstrated the best performance due to the top and bottom plates' presence and the keep away of critical stresses from the connection area. The RBS connections exhibited the weakest behavior due to absorbing excessive stresses and fast fracture and tolerating minimum vertical loads. Also, it is observed that in the designing of buildings exposed to the phenomenon of progressive collapse, the considerable axial load generated in the connections area should be considered in the design phase.

梁柱连接被称为钢抗弯框架中的基本组件。本调查研究了四种不同焊接类型的梁柱连接的连续倒塌行为，包括焊接无筋法兰焊接腹板弯矩 (WUF-W)、减少梁截面 (RBS)、焊接法兰板 (WFP) 和焊接法兰- 焊接带内部隔膜 (IW) 的腹板连接。已生成具有合适有限元建模的非线性分析，以评估柱移除情况下的连接性能。描述了载荷-位移曲线、断裂模式、Von-Mises 应力和其他可比较的理论结果。结果与现有的实验数据进行了验证。分析结果表明，所研究的模型 悬链线作用模式下大旋转梁柱连接区域发生整体失效。塑性应变积累发生在检修孔周围，失效是从这些区域开始的。每个被调查的连接在柱移除情况下都显示出足够的强度。由于顶板和底板的存在以及远离连接区域的临界应力，WFP 连接表现出最佳性能。RBS 连接表现出最弱的行为，因为它吸收了过多的应力和快速断裂，并能承受最小的垂直载荷。另外，在设计存在连续倒塌现象的建筑物时，应在设计阶段考虑连接区域产生的相当大的轴向载荷。