This article presents the results of numerical investigations of T‐joints made of high‐strength square hollow sections under axial and bending loads. The work builds on the experimental results of FOSTA project P1504 by using detailed finite element modelling. These models were validated against test results and include a calibrated break‐off criterion that represents punching shear failure. Systematic parameter studies examined the effects of steel grade, the ‐ratio, chord wall thickness, weld geometry and chord pre‐stressing. The results confirm that, for ‐ratios between 0.4 and 0.7, the current Eurocode design rules (prEN 1993‐1‐8) are conservative, even without the material reduction factor . However, for larger ‐ratios and thicker chord walls, the design rules tend to overestimate the load‐bearing capacity of the joints. For bending, tensile pre‐stressing improves resistance, which is underestimated by the current standard. The study suggests that adjusting the chord stress functions and including weld effects and effective width ratios could improve the accuracy and efficiency of designing joints for high‐strength hollow section structures.