Long-term Monitoring of a Piled Raft Foundation

Measuring strain and load sharing in the piles and raft of a 27-story London building throughout 30 months of construction

Piles can account for 10–30% of a building’s embodied carbon, yet foundation designs often rely on conservative assumptions. At Edge London Bridge, a 27-story building on a piled raft, Tyréns AKT used fibrisTerre Brillouin distributed strain and temperature sensing to validate those assumptions against field data. Fiber-optic cables attached to reinforcement cages instrumented two 35 m piles, two plunge columns, and a section of the raft. Hourly profiles over 30 months captured ground-heave tension and pile–raft load sharing at every construction stage. The calibrated models have since enabled smaller piles on subsequent projects, saving concrete, cost, and carbon.