The U.S. infrastructure is crying out for attention. According to the American Society of Civil Engineers, the country needs to spend $4.5 trillion by 2025 to fix the country’s roads, bridges, dams and other critical structures. But that’s not likely to happen soon, especially since government budgets at every level will be strained for the foreseeable future by the economic fallout from COVID-19.
One way to get the job done is to find alternatives to current methods of infrastructure construction. The global composites industry is exploring several technologies that could provide more cost-effective and longer-lasting solutions to these pressing needs. Here are three examples.
Bridge Repair Minus Traffic Jams
Failing bridges are a problem in many parts of the world. In the U.S. alone, more than 231,000 bridges need repair or replacement, according to the American Road & Transportation Builders Association. But bridges closed for repairs often result in unhappy motorists sitting in snarled-up traffic.
FiberCore Europe, based in the Netherlands, has developed a temporary bridge structure that could help ease traffic congestion in these areas in partnership with KWS (a Dutch infrastructure construction company and subsidiary of international construction company VolkerWessels) and in close cooperation with the Dutch Ministry of Infrastructure and Water Management. Made from lightweight FRP, the temporary spans can be placed on an existing bridge. This solution keeps traffic moving along the accustomed route while providing plenty of space underneath for contractors to repair road surfaces or transitions between the bridge and abutments.
The structure is called HUGO, which stands for HUlpbrug bij Groot Onderhoud in Dutch and translates to English as “temporary bridge for maintenance roadworks.” After extensive testing of HUGO, KWS is working with the Dutch Ministry to identify five bridge repair projects that will use temporary structures.
HUGO bridges are built with InfraCore® technology, which is specifically designed for use in heavy-duty, load-bearing structures. FiberCore Europe is the civil engineering and construction arm of InfraCore Company, which is developing, marketing and licensing this technology.
According to InfraCore Company, its technology overcomes the cracking and delamination problems of typical FRP bridges by creating a continuous structural connection of the glass or carbon fibers in a multi-layered laminate. The fabric layers partially overlay one another and are interconnected at a slight angle through the entire thickness of the laminate.
FiberCore has been building pre-fabricated, permanent bridges with InfraCore technology for 10 years and recently produced its one-thousandth structure. The company has also developed SUREbridge (Sustainable Refurbishment of Existing bridges), which extends the life and strengthens the structure of existing concrete bridges with the installation of InfraCore FRP panels over the existing surface.
The 295-foot HUGO prototype consists of a 29-foot middle span made from CFRP so it’s only 1.2 feet thick. The approach ramps on each side are built with two 59-foot GFRP sections plus a 15-foot metal ramp. “Keeping this element slender has the advantage of limiting the length of the approach ramps, saving cost and reducing weight,” says Martin Veltkamp, FiberCore’s design manager. It also provides a 6.5-foot clearance underneath the span for workers making repairs on the permanent bridge.
FiberCore manufactures the HUGO decks at its plant in Rotterdam using a one-shot injection molding system, with vinyl ester resin for CFRP bridge segments and polyester resin for GFRP segments. The entire injection process takes about 90 minutes, and workers can demold and finish the bridge segment the next day.
With this speedy production method, FiberCore can produce an average of five light-traffic bridges a week. “It’s really more of an industrial process than a building process,” says Simon de Jong, InfraCore’s founder and CEO.
Because of this factory prefabrication, HUGO decks can arrive at the project site with the grit road surface, railings and even the painted traffic lines installed. “We have pushed the line of what we can do in the factory and what we do on site, gradually taking on more and more so that the time on site is very short,” says de Jong.
The HUGO installation is simplified for contractors because the components are packaged as an entire system, including lightweight steel towers to support the bridge segments. A 65-foot bridge section weighs just 9 pounds, so builders only need light equipment to lift and move the elements and steel towers into place.
Once the work on the bridge is complete, the temporary bridge is removed and sent to the next bridge repair site for installation. This makes HUGO both a sustainable and an economical choice for transportation authorities that have long lists of bridge maintenance projects.
“The bridge will be a tool that KWS will reuse on a wide variety of infrastructure projects throughout the Netherlands,” says Veltkamp. “We are the first country in the world to be doing this, and I expect this will have huge fallout internationally.”
Bridges aren’t InfraCore Company’s only interest; the company is currently marketing its composites technology to shipyards and aerospace and hopes to expand to other areas as well. Its composite structures should soon be available in the United States. Orenco Composites, headquartered in Oregon, signed an agreement in March to license the application of InfraCore technology.
More Strength, Less Weight
Steel-reinforced concrete is a mainstay of the building industry throughout the world, but it could someday be supplanted by concrete reinforced with carbon fibers. In Germany, the Carbon Concrete Composite Project, known as Project C3, is pursuing the possibilities of this enhanced building material with the construction of the CUBE, a 2,368-square-foot structure made almost entirely with carbon fiber-reinforced concrete.
Funded by Germany’s Federal Ministry of Education and Research, Project C3 is a consortium of 160 science and industry partners that have been working together since 2014 to develop materials and technologies for carbon fiber-reinforced concrete. TU Dresden, a public research university and a Project C3 partner, is leading the design and construction of the CUBE.
Built on the Fritz-Förster-Plat square in Dresden, the CUBE will be an experimental building where researchers can study the suitability of carbon fiber-reinforced concrete from construction, structural and building physics viewpoints. The building’s two carbon fiber-reinforced sections include the box, which is a two-story modular building, and the twist shells, featuring two identical, double-curved structures turned 180 degrees to each other. A steel and glass façade will connect the twists and the box.
The precast concrete box is being manufactured in an automated concrete plant and should be ready by early fall. The twists will be produced on the building site, using the wet spraying method of concrete construction.
