A probabilistic framework for assessing vessel impact on bridges considering technical failures: insights from the Baltimore accident case study

This article presents new probabilistic approach to assessing the risk of collisions between ships and bridges, focusing specifically on the incident involving the container ship Dali and the collapse of the Francis Scott Key Bridge in Baltimore. Current risk models are significantly limited, particularly given the evolution of navigation practices and the adoption of ultra-precise positioning systems. The proposed method enhances predictive capability by incorporating three categories of technical ship failure: loss of power supply, failure of the main engine, and malfunction of the steering gear. A simulation-based reconstruction of the Dali incident was conducted using the NTPro 6000 full-mission bridge simulator. This reconstruction forms the basis for an in-depth analysis of four critical components: (1) the probable technical cause(s) of the accident; (2) key stakeholders and influencing factors in the risk profile of ship-to-bridge interactions; (3) engineering and procedural options for mitigating bridge strike incidents; and (4) expert assessment of feasible preventive measures, particularly those available to maritime pilots. The study includes the results of a targeted survey of maritime professionals, including pilots and captains. The survey aimed to evaluate the effectiveness of current preventive protocols and to identify potential gaps in training, coordination, and technical response in emergency situations. The findings provide valuable insights into the dynamics of maritime accidents in confined waters and propose a structured approach to enhancing risk assessment methodologies through the use of realistic failure scenarios and expert-informed analysis.