Composite materials can also deliver speed and flexibility for infrastructure repairs. QuakeWrap’s PileMedic® is made with multiple layers of carbon (or glass) FRP to form an extremely thin (1/1000 to 25/1000 of an inch), solid but flexible laminate. The material is coiled into 4-foot-wide rolls that can be 200 to 300 feet long and easily shipped anywhere.
Building crews shape PileMedic into the desired diameter for a pipe, pier or other application right at the site. Infused with additional epoxy, it forms a continuous wrapped column or jacket that can be filled with concrete.
“The laminate has a lot of strength in both the longitudinal and the transverse directions,” says Mo Ehsani, president and CEO, QuakeWrap Inc., and centennial emeritus professor of civil engineering at the University of Arizona. The thin laminate offers another advantage for submerged pile repair. Work crews can form the wrapped columns in sections above water and then push them down into position around the pier underwater. This reduces costs by limiting the number of divers required for installation work.
The U.S. Army Corps of Engineers has designated PileMedic the material of choice for emergency pier repairs at U.S. ports since all the components of the system can be stored on site, enabling a quick response.
QuakeWrap has used PileMedic to repair 500 badly-deteriorated timber piles at a private port in Virginia, as well as 100 piles in a demonstration project at the Port of Seattle. Another potential market is New York Harbor, where hundreds of thousands of timber piles support docks and major structures. Because the water is getting cleaner, marine borers – mollusks or crustaceans that live in warm seas and destroy wood – are moving in and attacking the piles at alarming rates. This threatens the structures these piles support, Ehsani says. A composite laminate wrapped around the piles would strengthen them and repel the borers’ incursions.
The company is using another new product ‒ a sheet pile repair system (SPiRe®) ‒ to contain potential runoff from a riverside steel bulkhead owned by a chemical product company in Virginia. The rigid 4 x 15-foot FRP panels are installed in front of the bulkhead in a continuous wall. A small gap left between the original wall and the impervious FRP panels is filled with concrete and reinforcing bars. Runoff can’t get through the FRP to the water, and oxygen doesn’t get through to the bulkhead.
“We prolong the life of the old steel wall, so it’s not only strengthening the wall but preventing corrosion as well,” Ehsani adds.