Evaluation of Seismic Behaviour of Hollow Fibre-Reinforced Polymer (FRP) Piles using Shake Table Testing

This study aimed at investigating the seismic performance of hollow FRP piles compared to traditional piles in fine sand and soft clay deposits using shaking table tests. A laminar shear box with a dimension of 1.0 m × 1.0 m and a depth of 1.0 m was employed to contain the soil medium and allow the soil to respond in the same fashion as the free field. Two types of composite group piles (2×2) made of Carbon Fibre-Reinforced Polymer (CFRP) and Glass Fibre-Reinforced Polymer (GFRP) along with a series of Aluminium piles were manufactured and embedded as frictional and end-bearing piles within the soil. Several monitoring instruments were used to observe the soil-pile response under variety of ground motions adopted from the 2010 Val-des-Bois Earthquake in Canada and the 1995 Kobe Earthquake. Seismic response of the foundation was strongly dependent on the stiffness provided by the soil, which was a function of the degree of softening and intensity of shaking. In both soil profiles, the foundation motion of model piles was higher than those of the free field under various intensity of input motions (0.02-0.16g). This was attributed to strong interaction between the soil and the foundation, and flexural stiffness of the model piles. However, the frequency content of the amplified motions appeared to be consistent for all model piles.