Rising sea levels and increasing storm intensity are driving the implementation of large-scale storm surge barriers globally to protect coastal communities and critical infrastructure. As these structures are increasingly located within major maritime access routes, their design introduces new navigational challenges that directly affect nautical safety. While extensive experience exists in the hydraulic and structural design of storm surge barriers, the navigational implications of alternative barrier configurations have received comparatively limited quantitative attention. Existing studies often focus on single configurations or rely on qualitative assessments conducted late in the design process, leaving a gap in systematic, configuration-specific methods that support early-stage design decisions.

The objective of this thesis is to develop and apply a quantitative assessment framework that enables systematic evaluation of the nautical safety performance of alternative storm surge barrier configurations during early design stages. The framework is grounded in the premise that, at this stage of design, nautical safety performance is most directly reflected in vessel maneuverability under constrained geometric and environmental conditions. Rather than attempting to predict accident probabilities or prescribe absolute safety classifications, the method focuses on configuration-dependent maneuvering demand and available control margins as necessary preconditions for safe navigation.

A structured assessment framework is developed that integrates spatial schematization of the navigational environment, critical environmental forcing scenarios, representative design vessels, fast-time ship maneuvering simulation, and quantitative nautical safety assessment metrics. These metrics describe maneuvering performance in terms of spatial, temporal, and control margins, enabling reproducible and configuration-specific comparison. Fast-time simulation is employed to ensure computational efficiency and repeatability, making the framework suitable for iterative application during early design phases.

The practical applicability of the framework is demonstrated through a case study of the proposed Bolivar Roads storm surge barrier in Texas. Multiple alternative barrier configurations are evaluated using the fast-time simulation model SHIPMA. Simulations are conducted for a set of representative design vessels under selected flood and ebb tidal conditions, using consistent spatial schematization and environmental assumptions across configurations. Simulation outputs are post-processed to derive the values of the quantitative safety metrics for each configuration.

The results show that nautical safety performance is highly sensitive to barrier geometry. Configurations featuring wider gate openings and more favorable alignment and siting consistently exhibit larger spatial and temporal maneuvering margins, reduced control effort, and more stable vessel behavior. Conversely, configurations with constrained openings or unfavorable alignment impose increased maneuvering demand and reduced controllability. These findings demonstrate that geometric design choices can substantially influence navigational safety performance and that such effects can be captured quantitatively using the developed framework. While the absolute values of the assessment metrics are subject to modeling assumptions and simplifications, the relative differences between configurations provide meaningful insight for comparative evaluation. As such, the results are not intended to replace expert judgment but to serve as structured input for pilot and stakeholder discussions, supporting transparent and informed interpretation of navigational safety implications.

This research contributes a systematic, maneuvering-based framework that bridges the gap between hydraulic design and nautical safety assessment in storm surge barrier projects. By enabling early-stage, quantitative comparison of alternative configurations, the framework provides capabilities that were previously unavailable in design practice. The case study illustrates the framework’s practical value and transferability to other navigation-constrained barrier locations. Future research should prioritize integration of configuration-specific hydrodynamic modeling, enhanced representation of human factors, and further refinement of assessment metrics to improve physical realism and decision relevance. ... Read more