Probability Analysis of Aberrant Ship Collision with Sea-Crossing Bridges Considering Wind and Current

The worldwide occurrence of numerous ship–bridge collisions has prompted a substantial concern regarding the safety of sea-crossing bridges. The majority of conventional risk models for ship–bridge collisions assume that collisions occur in inland waterways instead of sea waterways. Therefore, a new probability model should be established to assess the risks of ship–bridge collisions in sea waterways, considering the harsh navigation conditions such as strong wind and turbulent current in sea waterways. This study proposed a new risk assessment method to evaluate the collision probability of a ship with a sea-crossing bridge. Additionally, the motion state of a ship under the coupling effect of wind and current was analyzed to optimize the new probability model, and the drift trajectory of an aberrant ship was obtained. Moreover, the proposed model was applied to analyze the annual frequency of ship collisions at the Zhoushan-Daishan Sea-crossing Bridge in the East China Sea. For large tonnage ships, the annual frequency of ship collision was higher when calculated using the probability model based on the AASHTO Guide than that evaluated using the current model, whereas a significantly larger collision frequency was computed by the proposed model for small tonnage ships. Furthermore, we analyzed the relationship between navigation circumstances and the annual frequency of ship collision. The findings of this study will assist in appropriately assessing the risks of ship–bridge collisions for ships navigating through sea-crossing bridges under the influence of wind and current and provide a feasible method for improving the design and management of sea-crossing bridges.