Waterline Pile Cap Footings for Bridges Using Large Diameter GFRP Reinforcing Bars - Material Characterization

This research project, funded by the Florida Department of Transportation (FDOT), evaluates the use of Glass Fiber Reinforced Polymer (GFRP) bars to address the significant risk of deterioration in the waterline pile cap footings that support bridge piers built in tidal zones. Traditionally, concrete foundations are reinforced with steel bars up to #11 (36-mm diameter) with thick concrete cover and durability-enhanced concrete mix designs. Both current design standards ACI CODE-440.11(2022) and AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete (2018) do not include the use of #11 or larger bars, which are ideal for pile cap footings or elements that may be susceptible to large design forces including vessel collision or hurricane wave and wind loadings. Additionally, existing literature lacks scientific research and experimental testing for large diameter FRP bars. The objective of this research project is to perform a comprehensive physio-mechanical characterization of #11 or larger GFRP bars including tensile strength, transverse and horizontal shear and other relevant properties such as bond strength to concrete. To achieve this objective, a series of different tests were carried out in accordance with ASTM standards on #11 GFRP bars, produced from two different manufacturers