Geogrid-confined pervious geopolymer concrete piles with FRP-PVC-confined concrete core: Analytical models

2019 Institution of Structural Engineers The geogrid-confined pervious geopolymer concrete pile (GPGCP) with fibre reinforced polymer (FRP)-polyvinyl chloride (PVC)-confined concrete core (FPCC) is a new form of composite piles proposed in a previous study, which consists of a circular geogrid outer tube, a FPCC, and pervious geopolymer concrete (PGC) filled in between. For FPCC, the normal geopolymer concrete (NGC) was used to fill the FRP-PVC tubes. In this study, new analytical models are proposed to simulate the axial compressive behaviour of GPGCPs without and with FPCC. According to the characteristics of the mechanical behaviour of GPGCPs, analytical models are proposed which can predict the large axial strain behaviour. The unconfined concrete model proposed by the European Standards, and an existing popular FRP-confined concrete model are combined here. It was found that the analytical results are in good agreement with the experimental results. Based on the analytical models, the influences of different parameters on the axial compressive behaviour of GPGCPs have been investigated through parametric analyses.