6. Measurement of imperfections and geometric tolerances concerning warpage

Because hull buckling resistance is very sensitive to imperfections, any calculation must clearly identify the maximum permissible amplitudes associated with the characteristic resistance. Furthermore, the characteristic buckling stresses are determined by taking into account imperfections based on geometric tolerances likely to be respected during manufacture. It is therefore necessary to establish, by means of spot checks on the unloaded structure (except by its own weight) and with conditions at operational limits, that the geometric imperfections measured remain within the stipulated tolerances.

• Sway verification methods are given in Eurocode 3, part EN 1993-1-6 dealing with the strength and stability of shell structures. In EN 1993-1-6, three measurable imperfections, which have a significant impact on resistance to buckling, have been...