Flexural behavior of one-way concrete slabs reinforced with deformed GFRP bars

The flexural behavior of concrete slabs reinforced with Glass FRP (GFRP) presents differences from that of steel reinforced slabs and is usually accompanied by larger deflections and crack widths. Limited experimental and analytical data is available in the literature on this subject even though bridge deck construction is one of the potentially largest markets for FRP reinforcement. This paper presents phase one of an ongoing research program investigating the behavior of one-way concrete slabs reinforced with FRP bars. Nine slabs were tested in this phase, seven of which were reinforced with commercially available GFRP deformed bars. The test results and analysis of five of these slabs are reported herein. Parameters considered in this investigation include amount and size of FRP reinforcement and thickness of concrete cover. The slabs were tested to failure under four-point loading condition. Reported test results include flexural capacity, mode of failure, load-deflection behavior, and maximum crack width. Results are compared with analytical and modified empirical models for validation. It is concluded that, for the tested slabs, the ultimate moment capacity, crack width, and deflection can be predicted with acceptable accuracy using analytical models, Slab stiffness degrades rapidly after cracking and serviceability requirements become the design driver. For adequate service performance, slabs reinforced with FRP bars should be designed to be over-reinforced.