Kiyoshi Yamashita

Settlement and Load Sharing of Piled Raft of a 162 m High Residential Tower

This paper presents a case history of design and performance of a piled raft supporting a 162 m high residential tower. The 47-story building is a reinforced concrete structure and the average contact pressure over the raft is 600 kPa. The raft is founded on diluvial sand-and-gravel at a depth of 4.3 m below ground surface. Because the building has a base isolation system, differential settlement of the foundation is rigorously restricted. To reduce the differential settlement, a piled raft foundation consisting of thirty-six 50-m long cast-in-place concrete piles was adopted. To confirm the validity of the foundation design, field measurements were performed on the settlement of the foundation, axial loads of the piles, contact pressures between raft and soil and pore-water pressure beneath the raft from the beginning of construction to eight months after the end of construction. Based on the field measurement results, the foundation design was found to be appropriate.