Vessel collision is an important consideration in the design of bridges over navigational waters. This topic became particularly visible after the recent fatal accident in Baltimore. There is a need to revisit the vulnerability of bridges with regard to vessel collision. The proposed session will include presentations on statistics of accidents involving vessels (ships and drifting barges), sensitivity of structural components of bridges, in particular piers and abutments. Special consideration is required by a simultaneous occurrence of a combination of scour and collision. An extreme scour and extreme vessel collision is unlikely. Therefore, there is a need to collect the available information about occurrences of load combinations, in region and elsewhere to determine the type of vessel, weather conditions, water level (flood?) and other factors. The collision forces depend on the vessel (ship under power, drifting ship or barge).
Learning Objectives:
(1) Understand how to design bridges for vessel impact, statistical analysis methods, and potential revisions to vessel collision load combinations;
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Ship & Barge Collision with Bridges – Overview of AASHTO Vessel Collision Criteria and Lessons Learned Since Its Original Adoption in 1991
Presented By: Michael Knott
Affiliation: Moffatt & NIchol Engineers
Description: The collapse of the Francis Scott Key Bridge on March 26, 2024, Baltimore has increased industry and public awareness of the potential for vessel collision in busy coastal and inland waterways. The presentation will include background on the development of the AASHTO vessel collision design provisions and examples of historic bridge collapses due to ship and barge impacts. A brief overview of the AASHTO risk analysis procedures will be provided and how the basic analysis principles in the Bridge Design Code can be modified to incorporate complex channel geometries and modern navigation systems (regulatory requirements and electronic navigation devices). An overview of alternative pier protection systems will be provided (physical structures and potential vessel operation procedures). The summary will include major lessons learned using the Bridge Code and observations
Risk Analysis for Vessel Collision with Bridges
Presented By: Andrzej Nowak
Affiliation: Auburn University
Description: The design and evaluation of bridges that are exposed to navigational waters requires consideration of vessel collision events. The objective of this paper is to present a calibration procedure for the limit state functions with vessel collision. The procedure includes selection of representative bridges over navigational channels, formulation of the limit state functions, development of load and resistance parameters, selection of the reliability analysis procedure, calculation of the reliability for representative bridges, selection of the target reliability index, and then calculation of the load and resistance factors. The latter depends on the consequences of failure and cost analysis. The review of the available failure records shows that the most frequent incidents have insignificant impact on bridges, such as a barge drifting out of control. However, a ship under power can cause a total collapse as was the case with Francis Scott Key Bridge. The paper will present reliability indices will be calculated for limit state functions with vessel collision for representative bridges, assuming they are designed using the current code provisions. The target reliability indices will be suggested depending on site conditions (channel, vessel and bridge).
A Framework for Assessing the Collapse Risk of Harbour Bridges Due to Ship Collision
Presented By: Fadi Oudah
Affiliation: Dalhousie University
Description: The collapse of the Francis Scott Key Bridge in Baltimore has underscored the need for a structured and practical approach to assessing the risk of harbour bridge collapse due to ship collisions. Many older long-span steel truss bridges, not originally designed for vessel impacts, are particularly vulnerable. This presentation focuses on the key elements that a risk assessment framework should include to evaluate the likelihood of structural collapse if a bridge is struck by a design ship impact. The framework emphasizes the interaction between the superstructure and substructure, ensuring both local and global structural responses are adequately considered. It incorporates stochastic nonlinear finite element simulation to account for uncertainties in bridge response and existing conditions, combined with reliability-based methods to provide a systematic approach to quantifying and interpreting collapse risk. The framework is designed to be practical and adaptable to project-specific constraints, ensuring that the assessment process yields cost-effective solutions if the risk of collapse is found to be unacceptable.
Leveraging AIS Data for Vessel Collision Risk Assessment and Bridge Safety Enhancement
Presented By: Andrew Foden
Affiliation: HNTB
Description: Bridges over navigable waterways are critical infrastructure assets that face risks from vessel collisions, which can lead to structural damage, service disruptions, and even catastrophic failure. As vessel traffic increases due to economic growth and global trade, leveraging AIS data for bridge protection becomes increasingly vital. The Automatic Identification System (AIS) provides real-time tracking of vessel movements, offering a valuable data source for assessing and mitigating these risks. By analyzing AIS data, researchers and engineers can identify high-risk locations, evaluate vessel traffic patterns, and predict potential collision scenarios. The insights derived from AIS analytics help inform policy decisions, optimize bridge design, and improve maritime safety protocols. This data-driven approach enhances resilience, reduces the likelihood of collisions, and minimizes potential economic and environmental impacts. Ultimately, AIS-based risk assessment represents a crucial tool for safeguarding bridge infrastructure and ensuring the continued safety of both maritime and land-based transportation networks.
Ship Impacts on Bridges: AASHTO Code and Research
Presented By: Jason Miles
Affiliation:
Description: This presentation touches on the history of vessel collision code development in the United States and highlights methodologies used in the current edition of AASHTO LRFD Bridge Design Specifications. It also describes the different factors that influence risk due to vessel collision and offers suggestions for future research.