Abstract
This research investigates the use of glass fiber reinforced polymer (GFRP) bars to reinforce the bridge deck slabs as well as jointed precast bridge deck slab in prefabricated bulb-tee pre-tensioned bridge girders. The experimental program included two phases. In phase (I), six precast slab joint details between flanges of precast bulb-tee girders were developed incorporating GFRP bars with straight ends, L-shaped ends and headed ends, embedded in a closure strip filled with non-shrink cement grout or ultra-high-performance concrete (UHPC). A total of 11 actual-size specimens representing the one-way slab system with the proposed joint details, in addition to 5 cast-in-place control specimens, were built and tested to failure to examine the structural adequacy of the proposed joint details. Based on the results from Phase (I), the best joint was selected for further tests in Phase (II) to examine its fatigue life and ultimate load carrying capacity under vehicular wheel loading. A total of 8 actual-size, GFRP-reinforced, 3500 X 2500 X 200 mm concrete deck slabs were designed for this purpose according to CHBDC specifications. Ultimate strength, fatigue behavior and fatigue life of the GFRP-reinforced deck slabs were investigated using different schemes of fatigue loading, namely: accelerated variable amplitude fatigue loading and constant amplitude fatigue loading. Overall, the experimental results indicated that GFRP-reinforced deck slabs showed high fatigue performance. A new prediction model for fatigue life of the GRFP-reinforced deck slabs was developed. The failure mode of the tested composite slabs was punching shear. Correlation between the experimental findings and the prediction models for punching shear resistance available in the literature showed that the prediction models by CSA S806-12 (2012) and El-Gamal et al. (2005) can accurately predict the punching shear capacity of the cast-in-place and precast jointed bridge deck slabs reinforced with GFRP bars. In addition, the average observed mid-depth punching shear perimeter for the cast-in-place deck slabs and the precast jointed deck slabs were measured to be 1.25 d and 1.33d away from the sides of the loaded area, respectively, which are more than twice the corresponding distance specified in ACI 440.1R-06 and CSA S806-12 for calculating the critical punching shear perimeter.
Highlights
Reinforced deck slabs, cast-in-place or precast with closure strip and headed-stud field connection, when subjected to truck wheel loads. 2- Examine whether the glass fiber reinforced polymer (GFRP)-reinforcement ratio for internally-restrained deck slabs recommended by CHBDC Section 16 is adequate for ultimate, serviceability and fatigue limit state designs. 3- Develop empirical expressions for the predication of the ultimate load capacity and fatigue life of bridge deck slabs reinforced with GFRP bars in case of cast-in-place and jointed precast slab in Bulb-Tee girder system
Based on the experimental results in phase I and II, the following conclusions can be drawn: 1- The ultimate load capacity of GFRP-reinforced cast-in-place deck slab reinforced with the reinforcement ratio specified in CHBDC, is about 75% greater than that of a similar slab reinforced with steel bars
2- The 125-mm wide closure strip with projecting headed-end or L-shaped GFRP bars filled with ultra-high-performance concrete (UHPC) and the 200-mm wide closure strip with projecting L-shaped GFRP bars and filled with non-shrink grout had a load carrying capacity about 27% greater than that of a similar slab reinforced with steel bars
Summary
The intent of this research was to contribute to the efficient design of GFRP-reinforced concrete bridge deck slabs by developing experimentally calibrated models capable of predicting accurately their response when subjected to static and fatigue loading. A total of 16 cast-in-place bridge deck slabs and jointed precast bridge deck slabs in prefabricated bridge bulb-tee (DBT) were tested under static load to failure. A total of 8 full-scale cast-in-place bridge deck slabs and jointed precast deck slabs in prefabricated bridge bulb-tee (DBT) were tested under static load and two types of fatigue loading programs, namely: (i) accelerated variable amplitude fatigue (VAF) loading and (ii) constant amplitude fatigue (CAF) loading, followed by loading the slab monotonically to failure. Appendices A, B and C provide additional experimental findings for future use
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