Flexural Cyclic Testing of Precast Concrete Tunnel Segments Reinforced with GFRP Bars

Abstract

AbstractThe flexural behavior of precast concrete segmental tunnel linings reinforced internally with fiber-reinforced-polymer (FRP) bars under cyclic loading is still not investigated in the literature. Besides, the design of such members reinforced with FRP bars is not provided by current international design provisions. This paper investigates the behavior of precast concrete tunnel segments reinforced with glass FRP (GFRP) bars under cyclic flexural loading. In this study, a full-scale precast concrete tunnel segment with 3,100 mm length and 1,500 mm width was tested and compared to another control specimen reinforced with conventional steel reinforcement. The thickness of the tunnel segments is 250 mm. Segments are skewed at their ends rather than straight edges. Quasi-static compressive loading is applied in terms of percentage of maximum estimated displacement. Two cycles of loading and unloading were conducted for 1.25%, 2.5%, 5%, 10%, 25%, 50%, and 75% of maximum displacement. Subsequently, one cycle of loading up to failure was conducted. The experimental results are presented in terms of the general behavior of the tested specimens, flexural capacity, crack pattern, and mode of failure. The results of the current study show the efficiency of using GFRP bars as internal reinforcement for precast concrete segmental tunnel linings as an alternative to the conventional steel reinforcement. Furthermore, the results of the current study initiate major applications of non-corrosive FRP reinforcement in precast segmental tunnel linings.