AbstractConventional I‐beam‐to‐SHS‐column moment resisting connections are generally stiffened with external diaphragms in order to limit excessive deformation of the tube‐wall. Passing through plates welded to the tube is an alternative solution that can develop significant strength and stiffness. This solution has been applied to CHS column and initial findings from RFCS project LASTEICON were encouraging. RHS columns are also widely used in practice due to simplicity of connections manufacturing. The new RFCS project LASTTS aims to investigate the application of this technique of passing through plates to SHS columns using laser cutting technology.The objective of this paper is to present the behaviour of I‐beam‐to‐SHS column moment resisting joints using passing‐through plates under equal hogging bending moments. A finite element model using brick elements is firstly presented. This model is used to perform a sensitivity analysis varying passing through plates thicknesses as well as SHS column dimensions. The failure mode is caused by the flange plate buckling inside the tube. Analytical models are developed to determine the bending resistance and initial rotational stiffness of these connections.