Research on Offshore Super-Large Gravity Caisson Design and Prefabrication Scheme

With the trend of large-scale and deep-water development in marine engineering structures, the design and construction of super-large caisson foundations have become a multidisciplinary issue involving ocean engineering, structural engineering, and materials science. Based on the THE RIG project in Saudi Arabia, this study systematically investigates construction cases, structural design schemes, and prefabrication processes for gravity caisson foundations with both length and width exceeding 100 meters. Three structural schemes—reinforced concrete, all-steel, and steel-concrete composite—are compared, and four prefabrication methods are proposed and evaluated considering site-specific conditions. The results indicate that the “existing dock + segmented steel-concrete caisson” scheme offers significant advantages in terms of construction period and controllability when dock and navigation channels are available. In the absence of navigable channels, the “new shallow dry dock + integral steel-concrete caisson + floating elevation” scheme is more suitable. The proposed schemes and conclusions provide important references for the design, construction, and interdisciplinary integration of similar super-large marine structures.