Performance of precast concrete piles with GFRP dowel splices under combined axial and transverse cyclic loading

This paper presents an experimental program and analytical evaluation on the behaviour of precast concrete piles (PCPs) internally reinforced with glass-fibre reinforced polymer (GFRP) bars. Eight GFRP reinforced precast concrete segmental piles (PCSPs), were connected through epoxy-bonded dowel and compared with two monolithic precast concrete piles (PCPs) with no splices. The test parameters included dowel type, embedment length, bonding materials, arrangement of dowels and level of axial load. An innovative test setup was used to simulate real life loading scenarios, i.e., combined axial and transverse loads. The test results showed that the spliced pile specimens with embedment lengths of 30 times the dowel diameter ( d b ) provided 80% of the transverse capacity of the reference monolithic counterpart. This reduction was attributed to stress concentrations caused by the relatively lower elastic modulus of the epoxy compared to the surrounding concrete. The specimen with shorter embedment lengths (18.75–20 d b ) experienced premature bond failure, resulting in reduced transverse capacities by approximately 25% and 8%, respectively, compared to the 30 d b configuration. Moreover, increasing the axial load from 8% to 16% of the pile axial capacity resulted in approximately 12.5% increase in transverse resistance capacity and 42% decrease in the corresponding deflection. The strength of epoxy significantly influenced connections performance, with lower-strength epoxy reducing transverse capacity. An analytical model layer-by-layer numerical integration (LLIN) technique was adopted to reliably predict the axial-flexural-load capacity of the spliced GFRP-PCSPs as compared with the experimental results. The results reported in this study contribute to a better understanding of the behavioural differences between spliced and monolithic GFRP-RC pile systems for accelerated construction of jetties and bridges.