The effect of concentrated transversal force on the moment resistance of rectangular hollow steel section beams

Abstract This article reports on a preliminary investigation about the effect of concentrated transversal force on the bending moment resistance of rectangular hollow steel section (RHS) beams. Two six-meter-long specimens with yield strength of 300 MPa and cross-section size of 250×150×6.4 mm were subjected to bending tests using a four-point load configuration. A three-dimensional nonlinear finite element model was developed by using the software ABAQUS to simulate the flexural behavior of the RHS beams. The model was validated against the experimental results and subsequently used to conduct a parametric study. The investigated parameters were the force application method and the corner radius between the webs and the flanges of the rectangular tube. The results showed that RHS beams may undergo failure due to large localized plastic deformations beneath the concentrated force, whenever this force causes compression on the webs. The use of a doubler plate on both webs can significantly reduce the detrimental effect on the bending moment resistance. Moreover, the effect is shown to be more pronounced for rectangular hollow steel sections with larger corner radius.