High stiffener web height I-girders on large cruise ships are made of thin welded plates, which lead to noticeable weld distortion and stresses during manufacturing, and can affect the load-bearing characteristics of the structure. Therefore, in order to consider the influence of welding deformation, this study investigates the failure behavior of high stiffener web height I-girders.

This study uses the 450 mm I-girder as the subject of investigation. Based on the actual welding parameters, the welding deformations and stresses were calculated using thermo-elastic-plastic finite element method, which served as the initial state for nonlinear finite element calculations to simulate the structure's failure behavior under vertical loads.

The initial welding deformation increases the instability of the structure when subjected to vertical compressive loads, which greatly weakens the ultimate load-bearing capacity, and the ultimate load was reduced by 35.74%. However, the effect of the welding stress was less pronounced than that of deformation.

The results demonstrate that the welding at the T-joint affects on the structural load-bearing characteristics, and the weakening effect of welding deformation should be considered in the strength calculation of the actual ship structure, with appropriate reinforcement or corrective measures to be implemented.