Analysis of fillet-welded T-sections was carried out using the commercial finite element software ANSYS® for SM400A shipbuilding steel. To avoid the time consuming experimental technique, this model was validated with the existing experimental and numerical results. The vertical deflection, transverse shrinkage, and longitudinal residual stress were considered to validate the present model. After validating the model, the longitudinal, transverse, and normal plastic strains were collected from flange, web, and weld bead portions throughout the thickness and were averaged. These plastic strains were converted into corresponding longitudinal, transverse, and normal welding forces and were applied in an elastic model to obtain the distortions. The average welding force method was found to be very efficient in determining the distortions of welded structures. It was found that the proper distortion pattern for single-sided fillet welding can be obtained by incorporating the additional shrinkage forces from the weld bead.