Ferry Terminal Seawall Stabilization & Sinkhole Repair

The Customer

Hatteras, North Carolina is home to the iconic Cape Hatteras Lighthouse, boasting over 50 miles of beautiful shoreline. While the year-round population is about 3,000-4,000 people, this number spikes in the summer months to over 50,000+ visitors per week. The Coast Guard Station at Hatteras Inlet is also located on the southern end of the island. The nearby ferry terminal for this wonderful island is both necessary, and enjoyable for residents and visitors alike.

The Problem

A portion of the Cape Hatteras Ferry Terminal’s seawall was in serious need of repair. The seawall needed a solution to prevent further damage and ensure safety to the area.

When the original seawall was constructed, concrete piles were installed using water jetting, a process of using high pressure water to create cavities to install concrete piles into the ground to support structures above. Once the row of piles were in place, concrete panels were then set and sealed in between the piles.

The seal between the precast panels and the piles at the ferry terminal had weakened over the years, thus causing soil to pull through the wall, and into the ocean.

As a result, sinkholes began to form behind the seawall near the Coast Guard Station at Hatteras Inlet.

The Solution

The NCDOT contacted URETEK for an environmentally friendly, non-invasive solution to prevent further loss of soil behind the seawall. In order to fill the present voids and sinkholes in this environmentally sensitive area, URETEK’s Deep Injection® Process would be utilized.

URETEK’s hydro-insensitive structural polymer material, also known as high-density polyurethane resin, would be injected along the seawall. The process would repair the areas with present sinkholes or voids, and re-seal the panels/piles from the back side of the wall thus preventing the future formation of sinkholes.

To start the project, the joints of the panels needed to be located with the help of trained divers, who would also provide a live-stream video of the repair process for quality assurance. Next, injection tubes were driven down to depths of 20 feet along the seawall. The technicians then began to inject the URETEK polymer material. Once the seawall was fully stabilized, the tubes were then removed and NCDOT was able to complete any necessary cosmetic repairs.

By monitoring the process with the divers and live-stream video, the technicians were able to know immediately that the leaks were successfully sealed. These important precautions insured the repair was successful, and non-disruptive to the residents of Hatteras or the environment.


URETEK quickly and effectively repaired and stabilized the ferry seawall.

  • All soil leaks were successfully repaired.
  • The sinkholes forming behind the wall were filled, and the soil was stabilized.
  • The newly sealed joints, insured a stable, and functioning ferry terminal for residents, and vacationers alike.
  • The URETEK process was eco-friendly, safe, and non-invasive.