Analytical method to determine the crushing behaviour of girders with stiffened web

•A simplified analytical method is presented to evaluate the crushing force in deforming stiffened web girders.•A new theoretical model of the progressive plastic deformation of the stiffened web girders is developed.•A new simplified deformation model of stiffened web girder is proposed comprising two equal folding elements.•New formulae for evaluating the crushing force are proposed on the basis of this new folding deformation mode.•The predictions are compared with the experimental force–displacement responses obtained by the authors.

This paper presents an analytical method to evaluate the crushing force of girders with stiffened web subjected to local in-plane loads. A new theoretical model, inspired by existing simplified approaches, is developed to describe the progressive plastic deformation behaviour of girders with stiffened web, which is of considerable practical importance to estimate the extent of structural deformation within ship web girders during collision and grounding accidents. In the last two decades, various simplified methods have been proposed to describe the crushing characteristics of girders with unstiffened web, but the existing theories cannot capture well the crushing behaviour of girders with stiffened web. Therefore, a new simplified deformation model of girder with stiffened web is proposed comprising two equal folding elements and new formulae for evaluating the crushing force are proposed on the basis of this new folding deformation model. The predictions are compared with experimental force–displacement responses.