Behaviour of restrained concrete bridge deck slabs reinforced with FRP reinforcing bars under concentrated loads
While the expansive corrosion of steel reinforcement is a major concern in reinforced concrete bridge deck slabs, the non-corrosive fibre reinforced polymer (FRP) composite bars provide an excellent alternative reinforcement. This thesis investigates the behaviour of restrained concrete bridge deck slabs reinforced with different types and ratios of FRP reinforcing bars under static loading conditions. The research includes two different phases; experimental and theoretical investigations. In the experimental phase, nine full-scale deck slabs 3000-mm long × 2500-mm wide × 200-mm deep were constructed and tested to failure. Five deck slabs were reinforced with glass FRP bars, two deck slabs were reinforced with carbon FRP bars, one deck slab was reinforced with steel bars, and the last deck slab was constructed without any reinforcement (plain concrete). The deck slabs were supported on two steel girders spaced at 2000-mm centre-to-centre and were subjected to a monotonic single concentrated load over a contact area of 600 mm x 250 mm to simulate the foot print of a sustained truck wheel load (87.5 kN - CL-625 Truck) acting on the centre of each slab. The experimental results were presented in terms of cracking, deflection, strains in concrete and reinforcement, ultimate capacity and mode of failure. It was observed that the mode of failure for all reinforced deck slabs was punching shear with carrying capacities of more than three times the design factored load specified by the Canadian Highway Bridge Design Code (CHBDC). It was also concluded that the maximum measured crack widths and deflections at service load level were below the allowable code limits. The theoretical phase has two parts. The first part includes developing a finite element model (FEM) to analyze and predict the behaviour of bridge deck slabs reinforced with FRP reinforcement. The efficiency and accuracy of the computer model was verified by comparing its results to the experimental results. Then the FEM was used to conduct a parametric study on the most important parameters that are known to affect the behaviour of the deck slabs. In addition the finite element program was used to analyze a typical concrete bridge reinforced with GFRP bars. The second part of the theoretical phase includes developing a new punching shear model to predict the punching shear capacity of FRP-reinforced concrete bridge deck slabs. The proposed model can predict with good accuracy the punching capacity of FRP-reinforced bridge deck slabs as well as FRP-reinforced two way slabs. In addition, the proposed model gives better predictions compared to the different available punching shear models.
- Génie – Thèses