Experimental tests of different types of bolted steel beam-column joints under a central-column-removal scenario

Several structural collapse incidents indicate that failure usually started from beam-column joints when exposed to abnormal loads. If the connections are sufficiently robust and there is adequate axial restraint from adjoining structures, catenary action usually forms and gives rise to alternate load paths when affected columns are severely damaged, resulting in large deformations in adjoining beams and slabs. This paper presents seven experimental tests of the performance of common types of bolted steel beam-column joints under a central-column-removal scenario. The joint types including web cleat, top and seat angle, top and seat with web angle (TSWA) (8 mm angle), fin plate, flush end plate, extended end plate and TSWA(12 mm angle) are studied under the central-column-removal scenario. This study provides the behaviour and failure modes of different connections, including their abilities to deform in catenary mode. The test results indicate that the web cleat connection has the best performance in the development of catenary action, and the flush end plate, fin plate and TSWA connections could also deform in a ductile manner and develop catenary action prior to failure. It is worthy to note that tensile capacities of beam-column joints after undergoing large rotations usually control the failure mode and the formation of catenary action. A new tying resistance expression is proposed to consider the effect of large rotation. If large rotation is not considered in the design stage, the joints with poor rotation capacities would fail to achieve the design tying resistances. The test results also demonstrate that the rotation capacities of beam-column joints based on the experimental results in this study were much higher than the recommended values. (C) 2013 Elsevier Ltd. All rights reserved.