Abstract
The axial-shear-flexural interaction behavior of a double-span steel beam in a column-loss state is a complex phenomenon that demands more explanation. Nowadays, it is common practice to study the column loss scenario of a double-span steel beam using the pushdown method. Generally, two pushdown methods are commonly used: the Monotonic Pushdown Force (MPF) and the Distributed Pushdown Force (DPF) methods. Many current researchers adopted the MPF approach due to its practical and straightforward instrumentation for experimental testing compared to the DPF approach. However, the DPF approach would better approximate the actual collapse behavior of the structure in a column-loss event since it resembles the proper form of gravity loads. This paper aimed to demonstrate how these two approaches result in significantly different behavior in double-span steel beam collapse, particularly on the axial-shear-flexural interaction behavior. A finite element analysis using ABAQUS software was undertaken on a validated double-span steel beam model. In the MPF approach, the results have highlighted the importance of the tensile catenary action in the overall structural resistance of the double-span beam against collapse. The tensile catenary action dominated the load-resisting mechanism of the double-span beam at a large deformation state and interrupted the flexural resistance development. The stretching effect induced by the tensile catenary action has avoided the inelastic local buckling and allowed for greater rotation capacity on the beam assembly. However, under the DPF approach, the double-span beam has limited tensile catenary action build-up with high shear force development after the plastic hinge formation. The significant effects of the high shear force development on the double-span beam behavior were highlighted in this study.