This work aims at investigating the patch loading resistance of stainless steel and aluminium plate girders. Current design provisions are based on the plastic collapse mechanism observed in experimental and numerical studies conducted for carbon steel girders, disregarding the strain hardening capacities of stainless steel and aluminium alloys. At present, strength-curves approaches are used within European standards to deal with stability problems in metallic structures. In this regard, three parameters require special attention: the yield load for plastic resistance, the resistance function depending on element slenderness and the elastic buckling load. Recently, the calculation of the yield load for plastic resistance has been simplified after revision. In this work, the patch loading resistance of aluminium and stainless steel girders will be investigated numerically using finite element simulations. Improvements in the resistance models will be proposed.