Epoxy-Filled Fiber-Reinforced-Polymer (FRP) Jacket
The most effective encapsulation method involves placing a fiber-reinforced-polymer (FRP) form, or jacket, around a structural member and then filling the annular cavity created with a two-part epoxy grout, into which an aggregate (normally silica sand) is added. This process has many advantages over other methods.
First, when installed properly, the FRP jacket, the epoxy grout, and the structural member are bonded together, creating a monolithic structure. Due to the low absorptive qualities of both the FRP jacket and the epoxy, seawater cannot contact the structural member. This stands in sharp contrast to other methods which frequently result in saltwater intrusion and thus the continued degradation of the structural member.
Secondly, the annular space between the structural member and jacket is minimal (often 1/2 inch), as opposed to bags or jackets filled with cementitious grout (where the annulus is usually several inches or more). This serves to minimize the weight and wave loading on the structure.
Finally, epoxy-grout-filled FRP jackets have consistently performed better and lasted longer than all other methods employed over the past century. The first such FRP jacket installation, reported in 1971, is still in good condition.
