It is not easy to solve the troubles around the openings at the detail design stage, because there are a lot of concerning locations. There are not also clear design rules of classification societies. For more detailed strength analysis around holes on the longitudinal girder or transverse web below deck plate, it is also very difficult to decide the boundary condition (B.C) at both ends. Grillage analysis, which considers B.C and more detailed member arrangement, is used in simple analysis. Furthermore, refined mesh method, which use a part of member in the strength analysis, is used to decide S.I.Fs around holes. Component loads are applied to a refined mesh model separately and S.I.Fs according to component loading are calculated. S/F and B/M are decided from the grillage analysis and S.I.F for a given hole location is deduced from database and the results of grillage analysis.