FRP composite piles offer strength, corrosion resistance

Composite Advantage (Dayton, Ohio, U.S.) reported in March that the first project using its FiberPILE corrosion-resistant fiber reinforced polymer (FRP) piling system was completed. The pilings were used to replace aging timber fenders on bridges at New Jersey’s Cape May resort. (See “FRP composite piles chosen for bridge rehab at New Jersey seaside resort.”)  

Since the completion of the project, the FRP piling system has been generating interest. While marine piling products come in all shapes and sizes and materials – including wood, plastic, steel and concrete – FRP is said to offer a strong, flexible and corrosion resistant alternative for such structures. 

According to Composite Advantage, Department of Transportation (DOT) agencies tasked with replacing aging fenders are opting for eco-friendly, corrosion-resistant fiber reinforced polymer (FRP) pilings with increasing frequency. The company says larger vessels are driving the need for pilings that can protect ships, docks, canal entrances and the bases of bridges from damage.

Composite Advantage’s FiberPILE is made with a proprietary closed molding vacuum infusion method to produce high strength from its high fiber-to-resin ratio.

“FRP composites are orthotropic materials,” says CA president Scott Reeve. “That means we can tailor properties along each axis and in each direction. Fiber orientation is important because placing the majority of fiber in the axial direction optimizes bending properties while fibers in the +/-45 degree direction enhance torsional resistance and pin bearing. This makes our piles stronger and lighter than other products on the market.”

FiberPILE reportedly has the flexibility to bend under vessel contact and then return to its original shape without breakage or damage. Standard diameters range from 18 inches to 48 inches and the pilings can be fabricated in continuous lengths up to 110 feet. FiberPILE is said to have a design modulus of 5.7 msi and a strength rating of 55 ksi.  

“The unique combinations we’re able to engineer with FRP properties make it possible for us to achieve superior energy absorption,” says Reeve. “That’s why FiberPILE products can effectively absorb impact kinetic energy generated by head-on collisions from larger ships. In most cases, we can also reduce the number of FRP pilings a customer needs by as much as 50 percent when compared to steel or wood.”

Composite Advantage says hollow construction, light weight and low driving friction allow contractors to use standard equipment for installation. Additional design options include pile splices for longer piles or tight under-bridge driving; FRP wales for tight radius fenders; and traditional plastic timber wales (which can be coated with a brown plastic exterior to resemble cedar).