Waterline Pile Cap Footings for Bridges Using Large Diameter FRP Reinforcing – Material Characterization and Design

In Florida, the tidal zone poses a significant risk for corrosion of steel reinforcement in coastal bridges, particularly affecting waterline pile cap footings. The footings, which support bridge piers and columns, are currently not designed with fiber reinforced polymer (FRP) reinforcing bars. Given that corrosion can lead to costly and time-consuming repairs, using corrosion-resistant FRP bars could represent a viable and economic alternative with resulting long-term cost savings. Traditionally, pile cap footings are reinforced with steel bars up to #11 (1.375 in) in size, but no standards exist for #11 FRP bars. The AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete [1] allow for the design of pile cap footings with GFRP bars, offering a solution to corrosion concerns. To implement this, we need to demonstrate the practicality of using current maximum bar sizes and develop design guidance and material acceptance criteria for larger FRP bars. The objectives of this project included identifying further research needed for using larger FRP bars in waterline pile cap footings, developing material acceptance and design specifications for #11 glass FRP bars, and creating design examples to aid implementation. Additionally, recommendations for future research will be provided to extend the use of larger FRP bars to other structural components, considering the limitations of GFRP compared to steel. This project aimed to enhance the durability and longevity of coastal bridge structures by using larger diameter FRP reinforcing bars, reducing maintenance costs and extending service life. It will result in material acceptance criteria, design specifications, and practical design examples, promoting wider adoption of FRP reinforcement in bridge construction.