Progressive Collapse Resistance of Bolted Extended End-Plate Moment Connections

Abstract

When a progressive collapse occurs due to sudden column removal, the moment connections must have adequate strength and be able to bridge over the damaged element. The present study comprehensively investigates the behavior of eight different types of extended end-plate beam-to-column connections against progressive collapse. The proper finite element models have been extended to assess the behavior of these bolted connections under a sudden column removal scenario. Specimens were checked by nonlinear analysis method. The fracture modes, Von-Mises stresses, vertical load–displacement and load factor–displacement curves, load transferal mechanisms, and other analytical results comparative were reported in detail and discussed for various investigated beam-to-column connections. The analysis results revealed that the overall failure of the samples occurred in the connection region under the catenary action mode at large displacements. Also, the results were verified with available experimental data. Among all investigated connections, the highest stresses could be applied to the sixteen-bolt stiffened connection, and this sample had the most excellent behavior. In the design of buildings exposed to unusual loads due to progressive collapse, the significant axial force created in the connections should be considered in the design stages of these elements. Also, it is recommended that at least three rows of bolts are embedded in the bottom area of end-plate connections when the structure is at the risk of progressive collapse.