Steel Sheet Pile Seawall Corrosion Protection

Roen Salvage Company has partnered with Acotec to provide corrosion protection by applying the Humidur coating system on steel sheet pile walls using the DZI Mobile Cofferdam. With the Humidur coating system, we can repair and stop corrosion at a fraction of the cost of replacing the entire steel sheet pile wall.

The DZI Mobile Cofferdam can be quickly transported and set up to be used with almost any steel sheet pile dock wall. Once the mobile cofferdam is in place, a variety of work can occur inside the dewatered cofferdam, for example:

• Existing corrosion inspection by the owner and/or engineer
• Pressure washing to remove the corroded layer of steel
• Welding supplemental steel plates onto severely corroded areas of the wall
• Sand blasting to prepare the cleaned steel surface for painting
• Application of the corrosion-stopping Humidur coating; or
• Bolting on large pre-coated steel protection plates in front of the cleaned existing wall
• Progress inspections of the sheet pile wall by the owner and/or engineer

​Using this Humidur coating system with the DZI Mobile Cofferdam, Roen Salvage can rehabilitate over a mile of steel sheet pile wall in less than six months.

The DZI Mobile Cofferdam

In 1985 Acotec pioneered the original DZI Limpet Cofferdam with patented sealing technology. The DZI cofferdam provides safe, dry access to submerged steel sheet piling. The modular steel construction allows for containerized shipping to locations throughout the world. Sizes of the cofferdam are approximately 20 feet wide, and up to 30 or more feet deep. The cofferdam assembly includes dewatering equipment, platforms, illumination, ventilation, and electrical control boxes. The design provides safe and comfortable access for workers. Final on-site assembly is complete within two days.

After the cofferdam is ready for deployment by crane or gantry, the cofferdam is lowered along the structure and the pumps are turned on.

Self-adjusting seals create a tight seal against a variety of surface profiles. Dewatering is complete within a few minutes, and does not require the use of divers. Inspectors and contractors can immediately start working on submerged sections of the structure, and progress rapidly through a project.

Work starts with an initial cleaning to remove marine fouling and loose corrosion products. The cofferdam contains all debris and can be equipped with air separation equipment to prevent fugitive emissions. After cleaning, the contractor seals any leaks watertight. Inspectors can measure residual steel thickness and perform root cause analysis of corrosion mechanisms. The contractor can perform structural repairs to reinforce thin steel and return the structure to a good condition. Upon request, we will provide assistance with inspections, methods for weld repairs, and techniques to rapidly achieve a dry, salt-free surface. Corrosion experts can easily photograph corrosion patterns, take samples of corrosion products, and conduct various tests for bacteria. After surface preparation to near-white steel, the contractor can caulk, strike coat, and spray Humidur epoxy coating to stop further corrosion. After application, the contractor can immediately flood the DZI and move to the next position. The Humidur coating will cure underwater.

---

Featured Projects

Steel Sheet Pile Walls Rehabilitated at Hallett Dock #5 in Duluth, Minnesota 

In 2015, Roen Salvage Company rehabilitated 1,200 feet of severely corroded steel sheet pile wall for Hallett Dock Company using Acotec’s Humidur coating and DZI mobile cofferdam.

Over 12,000 square feet of corroded sheet pile wall was covered with pre-coated steel plates.  The voids between the protection plates and the existing piling were filled with stud-reinforced cement grout and sealed with marine epoxy grout.  Additionally, 1,200 feet of new timber fenders were installed. 

The project was completed in 5 weeks, well ahead of schedule.

Steel Sheet Pile Walls Rehabilitated at Duluth Seaway Port Authority

In 2010, Roen Salvage Company rehabilitated 6,000 feet of severely corroded steel sheet pile wall for the Duluth Seaway Port Authority using Acotec's Humidur coating and DZI mobile cofferdam system.

Over 60,000 square feet of corroded sheet pile wall was covered with pre-coated steel plates. The voids between the protection plates and the existing piling were filled with stud-reinforced cement grout and sealed with marine epoxy grout.

​The project was completed in 6 months, far ahead of schedule, with the port remaining fully operational throughout the project.

Steel Sheet Pile Wall Repaired in Okinawa, Japan

In 2008, Roen Salvage teamed with Acotec to perform a demonstration project for the U.S. Army Corps of Engineers at Port Naha in Okinawa, Japan. Since the 1980's, more than 3 million square feet of sheet pile wall using the Humidur coating system, but this would be the first project for the Army Corps. After completion of the project, the Army Corps published a report recommending implementation of this unique anti-corrosion system in the United States.

Click here to read the report (PDF, 4MB).