Flexural performances of pre-stressed concrete piles reinforced with hybrid BFRP and steel bars

In this study, pre-stressed concrete (PC) piles were reinforced with high-strength basalt fibre-reinforced polymer (BFRP) bars and steel bars to improve their flexural strengths and behaviours. Full-scale specimens with total lengths of 12000 mm and diameters of 600 mm were constructed and implemented with bending tests. Efforts were made to evaluate effects of non-prestressed reinforcement type and longitudinal reinforcement ratio on flexural performances of specimens. Meanwhile, J-factors were calculated to quantify deformability of all specimens. It's experimentally demonstrated that PC piles reinforced with BFRP bars exhibit much higher flexural capacity than those with steel bars. Moreover, cross sections of all specimens basically conformed to the assumption of plane section. Failures of PC piles reinforced with BFRP bars were attributed to gradual concrete crushing, while those with steel bars were speculated to result from excessive crack width. A simplified method for predicting flexural capacities of PC piles reinforced with BFRP bars was proposed. The predicted flexural capacities using the proposed method were in good agreement with the experimental results. Results of this study were expected to provide theoretical basis for broadened engineering applications of PC piles reinforced with hybrid BFRP bars and steel bars in marine structures.