Experimental testing and numerical modelling of steel moment-frame connections under column loss
Experimental testing and numerical modelling of steel moment-frame connections under column loss
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DOI：
10.1016/j.engstruct.2017.08.068
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发表时间：
2017-11
影响因子：
5.5
通讯作者：
F. Dinu;I. Marginean;D. Dubina
中科院分区：
文献类型：
--
作者：
F. Dinu;I. Marginean;D. Dubina
抗弯钢框架的梁柱连接应具有能够传递在正常预期负载条件下产生的力的能力。然而，当柱子由于意外荷载而丢失时，这些条件就会发生变化，力会重新分配到相邻的梁和柱上。在这种情况下，连接必须能够抵抗轴向和弯曲载荷的组合，并允许载荷重新分布，从而防止逐渐倒塌的发展。在本研究中，我们研究了四种类型的梁柱连接的抗连续倒塌性能，即焊接盖板法兰连接（CWP）、腰端板螺栓连接（EPH）、缩小梁截面焊接连接（RBS）和非加劲加长端板螺栓连接（EP）。建造了两个跨度框架，并在中心柱拆除情况下进行了测试，直至失效。实验测试的结果用于验证有限元模型。 CWP、EPH 和 RBS 样本表现出良好的延展性，悬链线作用对极限载荷抵抗力做出了重大贡献。此外，梁的极限旋转大于最新的《统一设施标准》建筑抗渐进倒塌设计指南中给出的变形极限。 EP 样本表现出最低的延展性和极限承载能力，在悬链线作用发生之前，成排的螺栓就处于拉伸断裂状态。此外，EP 试件的破坏模式表明，螺栓强化对于提高其抗连续倒塌能力是必要的。
The beam-to-column connections of moment-resisting steel frames should exhibit capacities that allow them to transfer the forces that develop under normally expected loading conditions. However, when a column is lost owing to accidental loading, these conditions change, and the forces are redistributed to the adjacent beams and columns. In such cases, the connections must be capable of resisting the combined axial and flexural loads and allow for the redistribution of the loads, so that progressive collapse development is prevented. In this study, we investigated the performances of four types of beam-to-column connections, namely, the welded cover plate flange connection (CWP), the haunch end plate bolted connection (EPH), the reduced beam section welded connection (RBS), and the unstiffened extended end plate bolted connection (EP), against progressive collapse. Two span frames were constructed and tested under a central column removal scenario until failure. The results from the experimental tests were used to validate finite element models. The CWP, EPH, and RBS specimens showed good ductility, with the catenary action making a significant contribution to the ultimate load resistance. Further, the ultimate rotations of the beams were greater than the deformation limit given in the latest Unified Facilities Criteria guidelines for design of buildings to resist progressive collapse. Specimen EP showed the lowest ductility and ultimate load resistance, with the bolts in the rows under tension fracturing before the catenary action could develop. Further, the failure mode for specimen EP indicated that bolt strengthening is necessary for improving its progressive collapse resistance.