Performance assessment of submerged caisson units under marine dynamic loading: Experimental validation and computational modeling for coastal energy infrastructure

Caisson breakwaters are widely used in offshore infrastructure; however, their performance under extreme hydrodynamic and geotechnical conditions remains insufficiently characterized, particularly regarding sediment dynamics and installation efficiency. This study proposes an integrated framework for evaluating caisson structural stability, hydrodynamic interaction, and seabed response, introducing novel design features, such as perforated chambers and hybrid jack-up installation, to enhance resilience in high-energy marine environments. A combination of Computational Fluid Dynamics (CFD) simulations Flow Science Three-Dimensional (FLOW-3D), Open Field Operation and Manipulation (OpenFOAM), wave flume testing (at 1:25 and 1:50 scale), and field calibration at tembak port was employed to analyze wave loading, scour behavior, and displacement. The numerical models incorporated sediment transport equations and settlement predictions, which were calibrated against physical and operational datasets. Results show that perforated caisson designs reduced wave reflection coefficients from 0.78 to 0.45, resulting in a 27 % decrease in seabed erosion. Meanwhile, increasing caisson mass by 15 % lowered displacement by 28 %. Installation time was reduced by 15 % via optimized ballasting, and material costs decreased by 18 % using High-Performance Concrete (HPC). The validated framework offers transferable design and performance metrics aligned with Permanent International Association of Navigation Congresses (PIANC) and Overseas Coastal Area Development Institute (OCDI) standards, supporting the development of cost-effective, durable, and environmentally sustainable caisson breakwaters for oil, gas, and petrochemical port facilities.