Skirt Suction Foundation – Application to Strait Crossings-PDF

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The paper examines skirt suction foundations—hollow, skirted structures installed by controlling water pressure inside their compartments—as an option for bridge substructures in water. Used offshore since the 1970s, they transfer loads through skirts embedded in seabed soil and require sufficient water depth for installation.<br /><br />Suction can reduce penetration resistance by creating upward seepage, provide additional downward installation force, and help level the foundation over uneven or sloping ground. Pressure changes can also generate passive suction under sealed baseplates, contributing to tensile resistance during short-term loads such as earthquakes or storms.<br /><br />For bridges, the authors identify several potential advantages: suction-induced preloading can reduce settlement during service; foundations can be fabricated offsite and installed quickly, limiting disruption to navigation and fisheries; and skirts can contain soft surface soils, accommodate seabed irregularities, reduce scour, and avoid soil improvement, dredging, noise, and vibration. The method is most suitable where water is over about 10 m deep and soils include cohesive deposits or sand with few gravel particles.<br /><br />Field monitoring showed that suction could control foundation inclination during installation on sloping ground. A field installation achieved final inclination of about 0.3 degrees without observed piping. Centrifuge experiments compared suction preloading with conventional jacking. In both approaches, reloading up to the previous maximum load caused little settlement, confirming a preload effect from suction.<br /><br />The authors conclude that skirt suction foundations can provide accurate installation, reduce settlement, and offer promising tensile resistance under seismic loading. These characteristics make them a potential foundation solution for bridges in suitable water and soil conditions.

Keywords

skirt suction foundations

bridge substructures

suction installation

seabed soil

offshore foundations

suction preloading

settlement reduction

tensile resistance

seismic loading

field monitoring