Stiffness assessment of welded I-beam to RHS column connections

•Evaluation of the initial stiffness of welded I-beam to RHS column connections loaded by in-plane bending moments though numerical models and the component method.•The finite element model was developed and validated with previous experimental tests.•The results of numerical parametric studies were compared with the equations of the component method existing in the literature.•Different formulations of the stiffness coefficient that represents the component “column face in bending” was evaluated and a revision of one formulation was proposed. This present paper evaluates the initial stiffness of welded I-beam to RHS column connections loaded by in-plane bending moments. Currently, there is a need to find mechanisms to satisfactorily determine the stiffness of these joints, due to the vast diversity of geometric characteristics. In this context, a numerical and theoretical study was carried out to obtain the initial stiffness through numerical finite element models and the component method. Thus, with a validated numerical model, 36 different connections were evaluated with column face failure and with variations in column thickness, beam flange width, and beam height. The initial stiffness results were obtained for the numerical models and compared with results calculated by the component method. The formulations available in the literature were considered, since the normative prescriptions still do not include formulations for tubular connections. The adopted springs model was described, composed of three components that correspond to the characteristic efforts of the connection: column face in bending, column lateral face in tension or compression and column lateral face in shear. The component “column face in bending” contributed mainly to the determination of the initial stiffness. In the current normative prescription, there are no equations for the stiffness coefficient of this component. Thus, three different formulations from the literature were evaluated. Finally, an adjustment was proposed to satisfactorily represent the evaluated component and the initial stiffness of the connections.