Construction methods · Driven piles

Prestressed concrete square piles

Solid square prestressed piles 300-900 mm on a side, cast in long-line beds and driven in single lengths up to 30-40 m, typical of US Gulf Coast, Florida and Southeast Asian practice. Robust in driving, good in marine exposure with adequate cover, and easy to make on site for large projects.

How bridges get built · Driven piles · Prestressed concrete square piles

Also called: PC square pile, prestressed square pile, PSC pile

How it is done

Cast in a prestressing bed, cure, and transport or lift from a site bed.
Drive with a hydraulic or diesel hammer through a cushion; jet or predrill through dense upper layers to control driving stresses.
Cut off, embed in the cap with exposed strands or dowels.

Where it fits

Marine trestles and viaducts, bridge approaches in sand and clay, sites where single-length piles avoid joints.

Where it does not

Rock, boulders, long piles through hard clay without predrilling.

Plant, pace and money

PlantCrawler rig or barge with leads, hydraulic hammer 8-20 t, jetting pump.

Productivity5-12 piles per shift depending on length and driving.

CostUSD 90-200 per metre for 600 mm.

Risks and controls

What goes wrong

Tensile cracking in soft layers, head spalling under hard driving, corrosion at cracks in the splash zone.

Quality assurance

Cushion condition, driving stresses monitored by PDA, crack inspection before driving.

Examples

Florida Keys bridges, Louisiana trestle bridges, Bangkok expressway approaches.