Structural analysis is performed on 12 models of T-joints from hollow cross sections reinforced with welded flange plate on the chord. Cross sections used for the verticals are sized from 40 to 70mm square section while the chord has size of 100mm square hollow section. For each vertical three different thickness are analyzed, also considering the thickness of the chord is same as the thickness of the vertical in the respective model. Joints are loaded with maximal in-plane bending moment. The results are drawn in a form of moment – rotation diagram and table result and compared to results obtained for same unstiffened models. Reinforcement used is based on the assumption that all the models comply with chord face failure mode, which is expected for the geometry used for these types of joints. It is concluded that the type of reinforcement is properly chosen since in all models there is an increase of the initial stiffness. Additionally, is summarized that the increase of the stiffness relies greatly of the solidness of the used sections.