Response of Piled Raft Foundation on Soft Clay Under Seismic Load

A number of researchers has extensively investigated the vertical load bearing mechanism of piled raft foundation, by applying elasticity theory and finite element method. The study on the load bearing mechanism under horizontal loading or during earthquakes, however, is very limited. This is partially because piled raft foundations are considered as raft foundations in the current design practice. Since the behavior of a piled raft foundation during earthquakes is considered fairly complex due to dynamic interaction among a raft, piles and a soil, the design procedure should include the effect of this mechanism in an appropriate manner. In other hands, the behavior of piled raft foundations under earthquake loading is an important factor affecting the performance of structures. Observations from past earthquakes have shown that piles in firm soils generally perform well, while those installed in soft or liquefiable soils are more susceptible to problems arising from ground amplification or excessive soil movements. This research comprises three major components: (1) Numerical modeling of piled raft foundation using finite element program (ABAQUSE), (2) verification of numerical program with dynamic centrifuge tests on clay pile-raft systems, and (3) performing parametric studies. The acceleration predicted by numerical method is well matched with the measured acceleration in a centrifuge test when simulating a piled raft foundation