Army Corps repairs canal bulkhead with innovative project
February 12, 2013
POINT PLEASANT, NJ -- When the U.S. Army Corps of Engineers needs to repair a dam outlet, marine bulkhead or any other infrastructure submerged in the water, it presents an engineering challenge. The added variable can make repairs more difficult, costly and time-consuming.
Ongoing repair work along the Point Pleasant Canal has been just that -- a challenge -- but through resourcefulness and innovation, the U.S. Army Corps of Engineers' Philadelphia District and its contractor are nearing completion of work.
The project involves repairing 8900 feet of a steel sheet-pile bulkhead along the canal. Work began in 2010 after the Philadelphia District awarded a $4.1 million contract to Abhe & Svoboda of Prior Lake, MN with funds from the American Recovery & Reinvestment Act.
The bulkhead repair project, scheduled to be complete in March of 2013, is the last remaining stimulus work still under construction for the U.S. Army Corps of Engineers' Philadelphia District.
"The contractors have been flexible, resourceful and met a number of challenges on this project," said USACE Project Manager Monica Chasten. "And the quality of their work has been very impressive."
The canal, approximately 150 feet wide and 1.7 miles long, was constructed in 1925, connecting the Manasquan River, about one mile from the ocean on the northern end, and Bay Head Harbor and the Metedeconk River on the southern end. It is widely used by pleasure boaters, the U.S. Coast Guard and New Jersey State Police Marine Services.
The sheet-pile bulkhead, installed between 1965 and 1972, retains the sides of the canal and protects the embankment. Bulkheads typically have a 50-year life. Sections of a bulkhead exposed to tide cycles are particularly vulnerable to rust and corrosion because of the daily exposure to sea water and oxygen.
Inspections dating back to 1983 revealed minor corrosion and USACE began analyzing and studying methods to address the issue.
"Through our test case, we found it was significantly cheaper to repair and coat the bulkhead rather than replace it," said Tony DePasquale, chief of Operations Division for the Philadelphia District.
Specifically, the team studying the matter found they could save approximately $25 million. The hard part, however, was working out the engineering of the project.
"This kind of work has never been done in the United States," said DePasquale. "The hope for us is that this project can be a demonstration for the whole Army Corps of Engineers as well as local and private interests. We're showing that we can rehabilitate this infrastructure and save money."
The work to repair the bulkhead involved moving a barge on site with generators, sand blasting equipment and a desalination station to produce freshwater for washing the steel. The contractor begins the process by maneuvering moveable cofferdams, temporary watertight enclosures, against the bulkhead, and pumping the area dry to expose the length of the steel bulkhead.
The crews use a high pressure wash to remove paint, rust and marine growth. They then check the thickness of the steel sheet-pile with an ultrasonic thickness gauge. Wherever they find spots corroded by more than half of the original thickness, workers weld steel plates to the existing structure. After a round of sand-blasting, the steel sheet-pile is ready for a special coat of marine paint.
Each stretch of bulkhead repair takes several days and the contractors move the cofferdams and progress to other areas.
"Our contractor pioneered a number of different features along the way," said USACE Project Engineer Rich DiMeo, who noted that the canal bulkhead includes three different types of sheet-pile depending on when it was installed. Each type has different interlocking features, requiring the contractor to modify and adjust plans as they progressed.
Two unique aspects of the project included the use of the moveable cofferdams and the application of a marine coat that can cure in wet conditions. Both of these features reduce the time and cost involved with work.
For the contractor, adapting to on-the-ground conditions has been essential.
"Getting everything to work from an engineering standpoint has been a challenge," said Justin Kotalik, a construction manager for Abhe & Svoboda. "There are a number of variables out here -- the weather, tides, boaters, the bridges, along with everything related to the steel bulkhead itself."
For Rudy Sorrells, an Abhe & Svoboda Safety Inspector who previously worked in the drilling industry, the project is a point of pride.
"It's prestigious and we're all pretty proud to be involved with the work," he said.
The current contract involves repairing half of the bulkhead along the canal. Moving forward, the Philadelphia District hopes to repair the entire length.
"It's imperative that we complete the job before the deterioration requires full replacement of the uncoated sections," said DePasquale.