Quasi-Static Cyclic Flexural Loading Behavior of Precast Reinforced Concrete Tunnel Segments with Glass Fiber- Reinforced Polymer Bars
The strength and behavior of segments of precast concrete tunnel linings (PCTLs) reinforced internally with fiber-reinforced polymer (FRP) bars under quasi-static cyclic flexural loading is one area in which no experimental research results are available. This research investigated the cyclic behavior of glass FRP (GFRP)reinforced PCTL segments, both experimentally and theoretically. Full-scale specimens with a total length, width, and thickness of 3100 mm (122 in.), 1500 mm (59 in.), and 250 mm (9.8 in.), respectively, were constructed and tested under quasi-static cyclic flexural loading. Two cycles of loading and unloading were applied at 1.25%, 2.5%, 5%, 10%, 25%, 50%, and 75% of the estimated maximum displacement, followed by a single cycle up to failure. The test parameters included reinforcement flexural stiffness (GFRP versus steel) and GFRP longitudinal reinforcement ratio. The hysteresis response, cracking pattern, residual deformation, dissipated energy, deformability, and secant stiffness damage index of the tested specimens were defined, estimated, and evaluated. The experimental results of this study show that the hysteresis cycles of the GFRP-reinforced specimens reflected stable cyclic behavior with no or limited strength degradation. Moreover, the test results show that the GFRP-reinforced specimens demonstrated adequate ductility index and deformability limits. A theoretical prediction according to the various current design provisions-including the flexural and shear capacities of the PCTL segments-was carried out and compared to the experimental results. The results of this study show the feasibility and efficiency of using GFRP bars instead of steel bars for PCTL segments under quasi-static cyclic flexural loading.
Read more
1
Filter 1
