Investigation of Wind and Earthquake Effects on an Offshore Knuckle-Boom Crane

This study presents a dynamic investigation of an offshore knuckle-boom crane subjected to wind and seismic actions. A finite-element model was developed in accordance with the actual geometry, material properties, and boundary conditions. Building on modal analyses previously reported in the literature, transient time-history simulations were performed to assess the displacement, velocity, and acceleration responses of critical structural components under realistic wind spectra and earthquake ground-motion records. As highlighted in prior research, such environmental loads are often underestimated by current design standards, potentially leading to excessive stresses and accelerations that may compromise structural integrity. To address this issue, damping devices were introduced to mitigate the vibrations generated by the analysed dynamic effects. The inclusion of these dampers significantly reduced both the peak accelerations and overall displacements of the crane, enhancing its stability and operational safety. The findings contribute to a better understanding of offshore crane dynamics under extreme environmental conditions and provide guidance for the implementation of vibration-control strategies in similar structures.