Stress Concentration Modelling in Internal Stiffeners of Ship-to-Shore Quay Cranes Legs Due to Structural Heightening

Featured Application This work focuses on modelling stress concentration in the internal stiffeners of ship-to-shore quay crane legs, which is critical when these structures undergo heightening modifications. The research aims to improve the structural integrity and safety of cranes during retrofitting or extension processes, where stress distribution can become uneven due to design changes using a new modelling procedure. Potential applications include enhancing the lifespan of quay cranes used in ports and ensuring their reliability under increased operational loads following heightening procedures.Abstract This paper presents a study on the modelling and estimation of stress concentration at the tips of leg stiffeners in ship-to-shore (STS) quay cranes, which is intensified in those on the sea-side leg extensions, which are more prone to crack formation, notably following structural heightening of the cranes. A computer-simulated database was generated, incorporating mechanical parameters and geometric features that impact stress concentration. These variables can then be integrated as inputs into a multiple linear regression model (MLR). This methodology offers an alternative to the finite element method (FEM) for the computation of stress concentration and deformations. At the same time, the statistical significance of the parameters influencing this scenario is determined, ensuring a comprehensive assessment of their impact on the studied phenomenon. The research underscores the importance of incorporating stress concentration and structural geometry considerations into crane design or modification, given their crucial role in preserving the remaining lifecycle of the structure. Crack initiation is significantly intensified in regions characterised by high stress concentrations, particularly in areas where there are geometric changes at the tips of the stiffeners, where local stiffness is altered. All of this is in combination with work cycles under the supported loads.