Finite element analysis of beam-column T-joints of rectangular hollow steel sections strengthened using through-wall bolts

A nonlinear finite element model is developed to analyze beam-column T-joints of Rectangular Hollow Sections (RHS) strengthened using through-wall bolts. The model was verified using experimental results for different beam depth-to-wall thickness (h/t) ratios and different bolts configurations and captured the full response and web buckling at the vicinity of the column quite well. The model was then used in a parametric study to investigate the effects of beam depth-to-width (h/b) ratio, span-to-depth (L/h) ratio, column breadth-to-beam depth (B/h) ratio, and welding the bolts to the webs, on the ultimate-to-plastic moment (M/Mp) ratio. As (L/h) increased from 4.9 to 7.9, (M/Mp) increased from 0.57 to 0.77 for the control joints and from 0.71 to 1.0 for the strengthened joints. Similarly, the limits of (h/b) and (B/h) at which strengthening allows the RHS beam to reach its full plastic moment are established. Welding the bolts to the beam walls enhanced ductility considerably with little increase in strength.