Investigation of welded top and seat angle connections under column removal event

A structure undergoes progressive collapse when a primary structural element fails, leading to damage of either a large part or even the entire structure. Beam-column connections are one of the major contributing structural elements which significantly affect the performance of the structure. Undesirable performance and damage to these connections can result in local failure and, in turn, lead to progressive failure. In the present research, behaviors of some beam-column connections were empirically and numerically assessed subject to column removal scenario. A number of tests were performed on some welded top and seat angle connections. Then, numerical models were created and validated by the experimental results. It was observed that the results of finite element analyses very well correspond to the test results. Moreover, parametric studies were done using finite element analysis. Behavior, failure limit states, and formation of the catenary action were investigated. Results demonstrate that adding a web plate or a web angle could be an appropriate method for upgrading the connection behavior. Furthermore, an increase in the angle thickness and length of the angle leg attached to the column can result in higher resistance to progressive collapse.