Preliminary Study on the Behaviour of Fibre-Reinforced Polymer Piles in Sandy Soils

Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corrosion when incorporated into piles. However, there is a gap in knowledge in terms of the behaviour of FRP piles under axial or lateral loading in soils. Thus, the aim of this experimental study is to assess the factors that influence the behaviour of FRPs under axial and lateral load in sandy soil. CFRP (carbon-fibre-reinforced polymer) and GFRP (glass-fibre-reinforced polymer) piles were tested in this experiment based on a special pressure chamber. The results show that the surface roughness (Rt), confined pressure (σc), and relative density (Dr) determined the shearing resistance of the soils and subsequently affected the bearing capacity of the FRP piles under an axial load. The flexural stiffness of the FRP piles was determined by the FRP type, pile dimeter, and aging in the environment, which were affected under the lateral load. In addition, an alkaline environment was more aggressive to the FRP piles than those aged in an acidic environment. The numerical modelling results show that the sand types, in terms of the dilation angle and Young’s modulus, also had a great influence on the behaviour. This feature should be considered more carefully in future studies.