Progressive collapse resistance of steel frame with beam to column transfer structure under a middle column-removal scenario

The application of Beam to Column Transfer Structure (BCTS) in practical engineering is more frequent to satisfy the requirement of space and economy of modern structure. However, the structure is unavoidable to increase the burden of the column in the lower floor, which will enlarge the risk of the structure subjected to progressive collapse. Hence, in order to explore the performance of the steel frame with BCTS on anti-progressive collapse, a numerical model is established by using Abaqus and it is validated by the test result. Based on that, a parametric analysis is carried out to discuss the effects of the Span to Depth Ratio (SDR) of the beams, and the Axial Compression Ratio (ACR) of the BCTS. The result indicates that the model with larger ACR leads to smaller load bearing capacity and Ultimate Deformation Capacity (UDC). Meanwhile, the model with larger SDR leads to smaller load bearing capacity but larger UDC. Moreover, it is found that it is inadvisable for unduly increasing the SDR to improve the contribution of the Catenary Action (CA) but decrease the contribution of the Flexural Action (FA). In addition, the better performances on progressive collapse can be observed as long as the models with the ACR is not greater than 0.06 in the RDS range from 11 to 19. Thus, the ACR of 0.06 is recommended as the limited value in structure design.