パイルド・ラフト基礎の地震観測より評価した杭応力と水平荷重分担率

抄録

Seismic observation on piled raft foundation subjected to unsymmetrical earth pressure was performed since after the 2011 off the Pacific Coast of Tohoku Earthquake. Accelerations of building, dynamic sectional forces of piles and dynamic earth pressures on both sides of an embedded foundation and beneath a raft were observed at 235 seismic events including an earthquake magnitude of Me7.1. The maximum acceleration of 32.2 cm/s² was observed on building foundation. Based on the seismic record, it is confirmed that a lateral inertial force of the building is related to shear forces and bending moments of piles, and lateral resistant force beneath the raft. It was also found that lateral load sharing ratio of piles was estimated about 10 to 20 % of the inertial force of building from observed record. The load sharing ratio between piles and raft and bending moments of pile could be approximately explained by simplified theoretical equations.