Also called: underwater concrete placement, tremie method, tremie pipe
Concept diagram (TheBridgeEng)
How it is done Design a concrete with 180-220 mm slump or a self-compacting mix with retarder for 4-8 hours of workability. Set the tremie to the base with a plug; start the pour and keep 1-3 m of embedment as the concrete rises; measure the level after every truck. Withdraw casing as the concrete rises, keeping the concrete head above the outside pressure. Overpour to bring sound concrete above the cut-off level.
Where it fits All bored piles and barrettes under slurry or water. Where it does not Mixes that stiffen before the pour ends; interrupted supply.
Plant, pace and money Plant Tremie pipes and hoppers, pump or crane and skip, concrete supply of 30-80 m3 per hour.
Productivity A 60 m3 pile is poured in one to three hours.
Cost Concrete at USD 150-250 per m3 plus placement.
Risks and controls What goes wrong Tip pulled out of the concrete, cold joints, slurry inclusions, cage floating. Quality assurance Pour log with level and volume per truck, slump tests every truck, CSL after 7 days.
Examples Every bored pile in the game's marine sites.
Related methods
Further reading EFFC/DFI Guide to Tremie Concrete for Deep Foundations · EN 1536