Steel tubes 400-2,500 mm in diameter, driven open-ended (the soil plug carries part of the base) or closed with a shoe (full displacement), spliced by welding to any length. High bending capacity, ideal in water, for scour and ship impact, and for liquefaction; the standard marine pile of Japan and Korea.
Also called: tubular steel pile, steel pipe pile, plugged pile
Concept diagram (TheBridgeEng)
How it is done
Drive with a hydraulic hammer, often from a barge with a template to hold position and rake; vibro-drive the upper part where permitted.
Splice on the barge with a girth weld and inspect ultrasonically; continue to the bearing layer or the required embedment.
Open-ended piles: monitor the plug; core out and fill with concrete or grout where the plug is unreliable; closed-ended piles: full displacement, higher driving resistance.
Cut off and connect to the cap with a welded plate or an embedded reinforced concrete plug.
Where it fits
River, estuary and sea piers; long piles through soft clay to a deep layer; pylon foundations in sand; sites with lateral load from ships, ice or earthquakes.
Where it does not
Rock at the tip without a socket (use PRD or bored piles), highly corrosive ground without protection.
Productivity2-6 piles of 40-60 m per barge per shift including splices.
CostUSD 250-600 per metre for 1,000-1,200 mm including driving; steel price dominates.
Risks and controls
What goes wrong
Buckling or tearing of the tip on boulders, running in soft layers, corrosion (allow 2-4 mm sacrificial thickness or coatings and cathodic protection in the splash zone).
Quality assurance
Weld inspection, driving records and PDA, verticality survey by template, plug measurement.
Examples
Tokyo Bay Aqualine, Incheon Bridge approaches, Gulf sea viaducts; the reference uses open-ended pipes for water piers over sand.