Residual ultimate strength of stiffened box girder with coupled damage of pitting corrosion and a crack under vertical bending moment

In this paper, the residual ultimate strength of stiffened box girder with coupled damage of pitting corrosion and a crack subjected to vertical bending moment was numerically investigated. Influences of the bending mode, crack length, angle and position as well as pit diameter, depth and density on the strength reduction characteristics were discussed. According to the finite element results, the ultimate strength decreases significantly with the increase of crack length when it is located in the primarily compressed area or destroys the connection of the panel and stiffener. Corroded volume loss is also a critical factor leading to the linear decline of ultimate strength. Superimposed strength reduction as a result of the pit and crack as they exist independently almost equals to the reduction induced by the coupled damage, indicting their effects can be simply composed. Four predictions as a function of actual/projected crack lengths and corroded volume loss were proposed to assess the residual strength of the girder with coupled damage.