Creative Composites Group shipped 12 GFRP wicket gates from its Augusta, Maine, facility to the Illinois River in March for installation on the Peoria Lock and Dam. Across the country, Orenco Composites in Roseburg, Ore., began work this year on 60 GFRP quoin blocks for lock gates on the Chittenden Lock and Dam in Seattle, with one-third slated for delivery in the fall. These are just two of the inland waterway projects in progress by composites companies for the US Army Corps of Engineers (USACE), which maintains 239 navigation lock chambers.
“The Corps is moving into FRP,” says Robert Germann, PE, technical manager for the South Atlantic Division of the US Army Corps of Engineers. “We’ve got 13,000 steel structures within our navigation and flood risk management portfolios. Based on a 50-year steel design life, we are on the cusp of replacing 260 hydraulic structures a year that were built between 1920 and 1980.”
The USACE started working on composite demonstration projects for large waterborne infrastructure in 2012, when its Engineer Research and Development Center (ERDC) collaborated with West Virginia University to design and build a prototype GFRP wicket gate. In 2015, demonstration gates made from E-glass and vinyl ester resins in a sandwich panel construction were installed on the Illinois River, replacing 12-inch thick, white oak timber gates. The wicket gates, which are a series of flat rectangular panels that can be raised and lowered depending on river conditions, were inspected in 2022 and are performing well.
Since then, the USACE has committed to investing in composite structures where they make sense to meet its new 100-year design life standards.
“We need to take that next step in material science technology and look at products that will live 100 years in adverse weather and environmental conditions,” says Germann.
Early composite applications
Composites fit the bill. They are corrosion resistant and low maintenance. Equally important, however, is the cost effectiveness of any material and product selected by the USACE, which is an agency within the Department of Defense and funded by Congress.
“We have limited funds to maintain, repair and operate gates, so we need to use our money wisely,” says Eric Johnson, PE, technical manager for the hydraulic composite structure program at USACE’s Inland Navigation Design Center. “Instead of putting up a steel structure that’s going to corrode and require new paint every 20 years over its life, why not invest in a material that has about the same upfront cost and doesn’t require as much maintenance over its lifetime?”
For one lock and dam location, Germann and his colleagues at the Army Corps compared life cycle costs for three tainter gates – a type of radial arm floodgate – made from steel and composites.
“If we look at a 100-year life cycle for a steel replacement, it will cost $200 million over that life span. If we replace that with FRP, we are looking at $20 million over 100 years – a 10 times savings,” says Germann. “That’s important to taxpayers and to us, so we are looking at how we can leverage those life cycle costs as we grow into an FRP program.”
As it ramps up the program, the USACE is initially looking at low-risk applications. For instance, static loads such as the force of the water pose a low risk, whereas dynamic loads caused by ice jams or a tow barge hitting a gate present a higher risk.
In February, the Corps hosted an outreach event for ACMA members in its Jacksonville District to highlight a low-risk application for conversion to FRP – the WP Franklin Lock and Dam on the Caloosahatchee River, Okeechobee Waterway. Approximately 15,000 vessels, mostly recreational, travel through the low-head lock and dam annually.
The quoin blocks that Orenco Composites are fabricating are another example of an ideal early application for fiber reinforced polymer. Quoin blocks are placed on the end of a miter gate (with a convex surface) and the lock wall (with a concave surface) to help ensure continuous contact of the miter gate against the lock wall. Orenco will manufacture 60 blocks in four styles, each approximately 18 inches long and between six and 12 inches wide.
“Locks and dams present a very good opportunity for composites companies,” says Eric Ball, president of Orenco Composites and a member of ACMA’s Board of Directors. “The Army Corps is smart to consider composite materials because the corrosion resistance is so much better than the materials historically used. You could build all these structures out of 316 stainless steel, but it would cost a fortune.”
Extensive FRP Opportunities
Creative Composites Group (CCG) has been working with the USACE since 2015, when its Dayton, Ohio, facility infusion molded three prototype wicket gates. One was delivered to West Virginia University to verify strength and deflection. The others were delivered to the Army Corps’ Rock Island District for demonstration projects on the Illinois River.
“They had a series of wicket gates, putting the FRP ones in line with wood and steel ones,” says Scott Reeve, who is in business development with CCG. “After a year, they pulled them out and inspected the FRP gates.” The FRP gates were performing as expected, so they were placed back in the river.
CCG designed the wicket gates using a wrapped core design to meet bending loads and other requirements. The sandwich structure features a foam core to meet another of the Army Corps’ requirements on this project – buoyancy. The wicket gates reside at the bottom of the river. When they are raised, the foam core helps ease the process.
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