When the City of Santa Barbara needed a building for high-horsepower variable-speed drives and large-scale electrical equipment at a desalination plant, the project constraints were clear: a tight footprint on an existing concrete slab, flanked by adjacent structures, and exposure to a highly corrosive coastal environment.
Conventional materials – precast concrete, CMU, or steel – would meet some requirements, but they would introduce tradeoffs in constructability, durability, or installation time. Instead, the project team selected a prefabricated fiber-reinforced polymer (FRP) building.
FRP is increasingly being considered in applications where corrosion resistance, weight, rapid installation, and durability are critical design drivers.
“FRP has been used for a long time in the marine industry, underground infrastructure, wet wells, and on piers where you see a lot of corrosion issues with traditional materials,” says Eric Ball, vice president of Orenco Composites.
In this case, a custom-engineered DuraFiber™ structure provided a corrosion-resistant building that could be installed directly onto the existing slab with minimal fieldwork. The result was a reduction in installation time, labor coordination, and long-term maintenance concerns.
Material Overview
FRP composite is a material made by combining a polymer matrix with reinforcing fibers to improve strength and performance. From a structural standpoint, the fibers provide tensile strength, the web-stiffened sandwich construction provides stiffness, and the matrix binds fibers, transfers shear, and protects against environmental exposure. Together, they’re a product that’s durable, lightweight, and resistant to corrosion.
“This combination of plastic and reinforcement can produce some of the strongest, most versatile materials (for their weight) ever developed by technology,” explains the American Composites Manufacturers Association’s Composites Lab.
The fiber itself varies widely, and each offers unique performance attributes for strength, weight, or sustainability targets. The resins, too, range from polyesters to “the fancy stuff that the aerospace industry uses,” Ball says. “In infrastructure and wastewater, we use polyester resins, vinyl ester resins, and other unique resins.”
Structural Advantages and Use Cases
Because of its constituents and their unique qualities, FRP excels in applications that require corrosion resistance, durability, light weight, structural strength, and a turn-key structure.
“In the water and wastewater fields, being corrosion-resistant is one of the biggest benefits,” Ball says. “Steel will corrode, aluminum will corrode to some degree, and wood can rot. So, any place where it’s wet or saltwater, FRP is a great application.”
FRP is also a highly durable material that stands up against the harshest environmental conditions, including 160-mph winds and heavy roof loads up to 100 lb/ft2. It’s impact resistant and UV resistant, too.
The material’s low density – often 20-25% that of concrete – makes it suitable for weight-critical and time-critical projects, too.
“We can build an FRP walkway that weighs 8 or 9 pounds per square foot. And if you were to pour concrete, it would be 150,” Ball says. “So now you’ve got a walkway that’s going to be just as durable and long-lasting as concrete without the corrosion or substructure strength requirements.”
When time is an issue, an FRP product can be turned around quickly. Using tight quality control standards, crews at Orenco Composites’ manufacturing facility use a vacuum infusion process to mold the one-piece buildings, which can then be finished with integrated systems like heating, ventilation, air conditioning (HVAC), load centers and panelboards, lighting, and other custom equipment.
“And then it can be placed on site just by bolting it down to a concrete slab, typically,” Ball says. “The alternative is often concrete tilt up or concrete block building, which takes multiple trades and can take weeks to install. So, there is a huge benefit in the field in terms of installation. That field time can be much lower and less intrusive.”
FRP is also a material that can be formed into different sizes, from large tanks and tank covers to single-piece buildings that measure 12 feet wide, 11 feet high, and 50 feet long.
“We can do two-piece buildings or even multi-piece buildings,” says Darren Simmie, sales manager for Orenco Composites. “And then if we need to do larger tanks, we also have ways to do a multi-piece structure.”
Design Considerations and Limitations
Like any construction material, FRP has its place, and it’s not appropriate for every situation.
FRP, however, is excellent for many applications, including projects where corrosion governs lifecycle cost, weight reduction provides logistical advantages, and schedule constraints favor prefabrication. Typical infrastructure projects include control buildings for lift stations, chemical feed buildings for water distribution systems, headworks buildings, or any time you need to protect or cover infrastructure equipment.
Industry experts are working hard at developing new standards for the material, notes Ball, which will raise awareness of FRP and acceptance of its use in infrastructure.
“There are a number of associations working on standards for FRP,” he says. “They just developed a new standard for FRP rebar in bridges, for example. And there are new standards for light poles and pultrusions for light poles for the electrical industry.”
FRP is not a universal replacement for traditional materials – but it is a viable option in an engineer’s toolkit, especially in durability-driven design scenarios.
Take a look at FRP and its many applications on Orenco Composites’ website, OrencoComposites.com or call 844-795-9568 to speak with us.
Sources:
Industry organization: American Composites Manufacturers Association
Market research: Research and Markets, “Fiber-Reinforced Plastic Market: Growth Outlook to 2032”
Scientific research: https://www.sciencedirect.com/science/article/abs/pii/S235201242400033X
Interview: Eric Ball and Darren Simmie in “Make It Clear” podcast