Performance of Fully Restrained Welded Beam-Column Connections Subjected to Column Loss

摘要

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.