This paper is focused on the behavior of bolted 3D beam‐to‐column joints, when the secondary beams are attached to the weak axis of the column by two additional plates welded between the column flanges. In this joint configuration the component column web in tension is modifying by the presence of the additional plates that must be considered in the stiffness evaluation. Moreover, the stiffness of this component is different in case of double‐sided and single‐sided joints. Therefore, based on the result of a parametric study with finite element models, two different mechanical models for the stiffness of the component column web in tension are proposed for double‐sided and single‐sided joints.