In the previous study, basic examinations were made on the COD in small structural models with artificial slits in the structurally stress concentrated regions to develop a quantitative estimation method of flaws existing in stress concentrated regions. As a result, it was made clear that flaws in stress concentrated regions could be quantitatively evaluated. This study using larger structural models aimed at establishing a more general strength estimation method by experimentally determining variations in the structural stress concentration, effect of notch lengths and combined effect of welding residual stresses and material deterioration.