Marine Encapsulation
Completion of this set of epoxy filled FRP H-Pile encapsulations was facilitated by using custom designed clamps. (Delaware River, DE)
Substructure has had the opportunity over the years to observe and critically evaluate the many types of pile encapsulation methods utilized in the industry.
Epoxy Filled Fiber-reinforced Polymer (FRP) Jacket
The most effective method involves placing a fiber-reinforced polymer (FRP) form, or jacket, around a structural member, and then filling the annular cavity thus 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 that 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, compared to other methods that have been employed over the past century, epoxy grout-filled FRP jackets have consistently performed better and lasted longer than all other methods. The first such reported installation in 1971 is still in good condition.
Performance Differences Between the available Epoxy Grouts and FRP Jackets
According to the data supplied by the various manufacturers, there is little performance difference amongst the variety of epoxy grouts and FPR jackets in the industry.
The real differences arise in the installation of the product. Without proper surface preparation, the epoxy polymer will not achieve the manufacturers rated maximum adhesive bond to the surface of the structural member.
To address this problem, Substructure designed and built a cleaning device that produces a clean, near-flawless surface far more quickly than other methods employed in the trade. The quality of the prepared surface ensures that the epoxy polymer can achieve the greatest bond strength. In addition, the reduction in cleaning time greatly reduces our clients’ expenditures on labor.
Substructure's Patented Advanced Pumping System (USPTO Patent # 7357564)
Another vital implement utilized in the encapsulation process is the apparatus for pumping and mixing high aggregate plural components of differing viscosities.
Due to our dissatisfaction with the performance of available epoxy pumps on the market, Substructure has over the past several years developed an advanced pumping system for high aggregate plural components.
Now completed, our patented pumping system is compact, efficient, safe, and reliable. Understanding that high pressure and aggregates are a recipe for wear, design considerations for ease of, in the field, maintenance and serviceability were given very high priority. United States patents are currently granted on both the pumping system and the static mixer utilized for combining the epoxy components and aggregate.
Worldwide Pile Encapsulation Systems Experience
We have installed pile encapsulation systems throughout the world. Some of our recent projects include installations at the Naval Testing Range Fuel Pier in Kwajalein, Republic of the Marshall Islands, the Earle Naval Weapons Station Pier in Leonardo, New Jersey, and the Oceanport Industries facility in Claymont, Delaware.
Substructure has also served as a consultant on similar projects in a variety of locations as diverse as the South terminal pier on Grand Turk, Turks and Caicos Islands and at the Ontario Power Des Joachims Generating Station in Ontario, Canada.