ABSTRACT
The basic theory governing the design of box girder bridges applies to other thin-walled structures, such as ships, which are built up from thin plates stiffened to increase strength. Thin-walled structures can have a ‘post-buckling’ reserve of strength, meaning that the failure stress can, in some circumstances, be higher than the elastic critical value. This is true for shear buckling of stiffened plates. For an efficient design, engineers aim to raise the buckling stress close to the yield stress. An efficient design will achieve buckling stresses close to the yield value. The Gordon–Rankine equation is then used to estimate the buckling strength of this ‘equivalent column’. Therefore, plate buckling checks also need to be carried out for the individual plates in the panel using the approach described earlier for plate girders. The moment capacity is estimated by setting the extreme fibre stress equal to the design buckling stress for the stiffener.
