The composite bridge structure incorporates Fiber Reinforced Polymer materials (FRP) instead of traditional steel reinforcement.
The 60-year-old bridge over the Halls River in Homosassa (Florida, US) was decided to replace with a new one by implementing contemporary technologies and materials. The project is being controlled by the FAMU-FSU College of Engineering and the University of Miami College of Engineering that are monitoring every aspect, including research and testings.
As reinforcing materials, they incorporate glass, carbon, basalt and hybrid composites. Construction started in January, 2017 and is scheduled to be completed in late 2019. All parts of the bridge use some type of FRP material: supporting piles, beams and bridge deck, retaining walls, guard rails. Particular attention was paid to the use of salt water in concrete mixes.
When recycling components of old road surface, it is necessary to wash out salts accumulated after processing. Furthermore, to make concrete mix, only fresh water is used since steel rebar is affected by salty aggressive media resulting in structure deterioration. The process requires large consumption of clean fresh water.
Composite structures (FRP), a class of corrosion-free materials, are resistant to aggressive salty media. Special research on this issue have been carried out during the development of Seacrete.
Composite reinforcements (Basalt Fiber Reinforced Polymers) or (BFRP) manufactured by Basalt World Сorp were used in this project, in conjunction with U-Miami’s testing of Seacrete, a salt water concrete mix which cannot be used with traditional black steel due to concerns of rust and spalling.
commented Matthew DeFrancesco, Basalt World Corp.
The original budget of $6.1 million grew to $ 7.6 million during the construction. The Florida Department of Transportation (FDOT) claims that composite reinforcing elements increase the construction cost by about 30%. However, a higher construction cost will pay off due to reduced maintenance cost and a longer useful life of composite structures.
Translated by Olga Yurchenko