The role of composites in infrastructure is increasing | Composites World

From bridges to steel bars and piles, composite materials can save installation and life cycle costs compared to steel and concrete. #Basic Structure#Function#frprebar
Arch bridge system. AIT Bridges’ arch bridge system uses woven fiber reinforced polymer (FRP) tubes filled with concrete. It can be applied to various bridge structures with spans up to 80 feet. Source | AIT Bridge
Aging infrastructure is a global problem that is often mentioned. Bridges, waterfronts and other buildings need to be repaired and in many cases replaced. Composite materials have the advantages of corrosion resistance and durability, help reduce the maintenance cost of the structure and extend the service life, help save life cycle costs, and have long-term economic advantages compared with traditional materials (such as steel and concrete). Many advocates in the composites industry, from material suppliers to manufacturers, are working hard to spread awareness of the benefits of advanced materials for global infrastructure renewal. Resistance to change, worries about unit material costs, and doubts about the performance of new materials have proven to be difficult obstacles for advocates of advanced materials to overcome, but all of these are gradually beginning to change.
Lightweight and safe. The composite manhole cover occupies about one-third of the manhole cover made of traditional materials, reducing the possibility of injury caused by manual operation. Source | Fiber Rock
Fibrelite (Skipton, UK), OPW brand (Hamilton, Ohio, USA), Dover Company (Downers Grove, Illinois, USA) specializes in the production of composite material channels and manhole covers, and has been aware of it in the past ten years The transition to composite materials is about as the metal and concrete outer layers are gradually replaced by composite materials. Jo Stott, Fibrelite’s marketing director, pointed out that corrosion resistance, light weight and higher load ratings are the reasons for this shift.
Fibrelite’s composite cover layer accounts for about one-third of the traditional material, which helps to reduce the damage of manual handling while maintaining mechanical properties. In many cases, the cover plate can be manufactured to fit the existing frame, thereby reducing installation time and cost. Stott said: “The market is maturing, and customers are becoming more and more satisfied with the way this switch is used.” “This is driving changes in the rest of the market.”
In the battle es. The C-type composite access cover has many advantages, including light weight, corrosion resistance and non-slip patterns, and can provide a safe walking surface. Source | Fiber Rock
As people become more aware of the advantages of composite materials, many manufacturers and suppliers said that the dialogue with civil engineers has shifted from resistance and suspicion to changes in material properties to other factors (such as the cost and performance of materials). doubt. That is a good thing. The goal is not to replace traditional materials, but to allow engineers and designers to fully understand the potential of composite materials so that they can make informed decisions.
“We know that we will not replace steel; steel has a very certain position in the market. Precast concrete reinforced with steel also has a place in the market.” CEO and Director of AIT Bridges (Brewer, Maine, USA) Chief Brit Svoboda said. AITBridges is an engineering and manufacturing company specializing in the manufacture of bridge composite materials. He said: “However, there are absolutely reasons to add alternative technologies that use advanced materials to increase the service life, provide lightweight transportation and mobility for [infrastructure] products, and if any, can drive the market to achieve better performance. specification.”
According to Scott Reeve, President and CEO of “Composite Advantage”, the company has manufactured very large composite structures for the infrastructure market, and the focus of discussion has shifted from the function of composite materials to Cost and maintenance. He said: “When I introduce designers, engineers, and contractors, there are very few questions about structural capabilities or structural integrity.” Instead, Reeve found himself talking about the same problems faced by precast concrete and other traditional materials. , Such as how long the material will last, how well the joints are maintained over time, and what maintenance needs to be performed. To
In the United States, new legislative work such as the IMAGINE Act (New Material Innovation for U.S. Growth and Infrastructure) introduced in August 2018 is helping to raise awareness of the potential life-cycle cost savings that composite materials can provide for infrastructure projects.
“American leaders pointed out that the United States needs more than one trillion dollars in investment to repair bridges, water supply systems, dams and power grids,” said Tom Dobbins, president of the American Composite Manufacturers Association. (ACMA, Arlington, Virginia, USA). “Composite materials have unique advantages and can provide realistic solutions to meet this demand.”
“The legislation that encourages state agencies to use [composites] and demonstrates its benefits has been praised affirmatively,” said Greg Brassa, a licensed engineer and co-founder of Coastline Scientific Composites (Lancaster, PA, USA) Said Gregg Blaszak. A consulting company that cooperates with manufacturers of FRP composite products. “Once these benefits are understood, these materials will and must be able to exist independently.”
For the past 15 years, Coastline Composites has been helping manufacturers of FRP composite products develop infrastructure applications. The company began work in the marine and coastal markets, launching FRP sheet piles and FRP bridge protection systems. Blaszak noticed the beginning of a dramatic change in the use of composite materials in infrastructure.
“As the years go by, we start to see more engineers really start to study these types of materials, because they are maintenance-free in most cases,” Blaszak said. He said that an example is that more and more projects specify the use of glass fiber reinforced concrete to reinforce concrete structures to replace traditional steel reinforcement.
FRP reinforcement. Composite steel bars are a substitute for steel bars, which have stronger corrosion resistance, durability, light weight, easy installation, higher tensile strength and longer service life than traditional steel bars. Source | Owens Corning
He said: “Glass fiber steel has a history of more than 30 years, but now it is being used more and more frequently to reinforce concrete structures to replace traditional steel.”
Corrosion of steel bars is the main reason for the deterioration of concrete structures. The service life of concrete reinforced with steel bars is limited to around 25 years, instead of the 75-100 years once estimated. Composite steel bars, such as those produced by Owens Corning (Toledo, Ohio, USA), are alternatives to steel bars. Their advantages include corrosion resistance, increased durability, light weight, ease of installation, and greater tensile strength. High and longer service life. Owens Corning’s Fiberglas rebar is made of glass fiber roving in a vinyl ester resin matrix, which is ideal for structures exposed to deicing salt, sea water or other corrosive agents. Rebar is available in #2, 3, 4, 5, 6, 8 and 10 diameter steel bars in 20 feet and 40 feet long, as well as custom diameters. Later in 2020, the company will launch a new type of composite rebar called Pinkbar, which is designed to be lighter and stronger than steel rebar.
Christopher Skinner, Vice President of Strategic Marketing for Composites at Owens Corning, said: “I hope that glass fiber rebar will continue to develop in structural applications and in leveling applications.” Compared with steel, the contractor’s strength and weight are reduced, which greatly improves the crew’s productivity. I expect that the durability of composite materials will soon become a consideration in purchasing decisions. ”
Blaszak believes that in addition to steel reinforcement, FRP is gaining momentum in infrastructure projects, because in some cases, repair costs exceed the initial cost savings achieved through the use of traditional materials.
“We have begun to see more and more agencies, such as the Navy and some more advanced Departments of Transportation (Department of Transportation) considering the future cost of repair or replacement because they have personally experienced the work of repairing deteriorated structures. Very expensive is usually accompanied by severe damage to the community and the public (for example, bridge closures),” Brasac said. “Although initial materials and construction costs are important, they are not always the only determinants of material selection.”
Quick installation. Composite Composite’s Fiber Reinforced Polymer (FRP) FiberSPAN system was selected as a fast, lightweight, and corrosion-resistant solution to repair an 87-year-old bridge in Michigan, Indiana, USA, which was bent due to low temperatures. Source | Comprehensive advantages
According to a 2019 report from the American Road and Transportation Builders Association. (Washington, DC, U.S.) There are more than 47,000 bridges in the U.S. that are in poor condition and need to be repaired immediately. Of the approximately 614,400 bridges in the United States, approximately 245,000 have exceeded their estimated service life of 50 years. In addition, traditional bridges will continue to reach a state of disrepair as they continue to age, and the situation of a country on the edge of a cliff in infrastructure has become the focus of attention.
The new bridge project will continue to provide examples of how composites and advanced materials can help rebuild fragile infrastructure and create new lightweight, corrosion-resistant, and sustainable structures that can stand the test of time and elements. In addition, composite materials can achieve bridge customization, versatility and speed up the time to market, which traditional materials usually cannot do. Companies such as Composite Advantage and AIT Bridges are working to repair existing bridges and build new bridges that may exceed the life of existing structures.
For example, in February 2019, a record low temperature caused the Franklin Street Bridge in Michigan, Indiana, USA to bend. This is an 87-year-old front bridge that uses counterweights to raise and lower its span, thereby providing A pass was provided for the passage on board. The fiber-reinforced polymer (FRP) FiberSPAN system of Composite Composite was selected as a fast, lightweight, and corrosion-resistant solution to repair the brittle concrete blades and steel brackets of the bridge.
Reeve said: “Traditional methods require temporary steel plates until the weather is warm enough to meet the 28-day concrete curing requirements.” “But that will take several months. This also means paying for two repairs and closing down. Passed the bridge twice. The need for light weight eliminated most material choices.”
In order to solve this problem, Composite Advantage prefabricated the panels with mechanical clamps to bolt the deck to the steel trusses. The FRP supplier was able to design, prefabricate, transport and install the panels in just 32 days, allowing the bridge to reopen in April 2019 (more information on the company’s Franklin Street Bridge project).
Shared usage path. Composite Advantage’s FRP FiberSPAN system was used to create a new shared path along Lake Tahoe on Interstate 28 in Nevada. The light weight of the FRP solution allows workers to meet the construction requirements on uneven slopes in the area. Source | Comprehensive advantages
In addition to repairs, Composite Advantage can also work on new bridge projects. In June 2019, the Nevada Department of Transportation (NDOT) and the Tahoe Transportation District opened a new shared-use path on Interstate 28 in Nevada. The path was manufactured using the company’s FRP FiberSPAN system. It is a two-lane hillside road, 11 miles adjacent to Lake Tahoe. Undeveloped coastline. Thirty-two 40-foot bridge span sections were installed, creating five distinct bridges that were used in areas where the slope was too large to provide a flat walking surface. The goal of shared routes is to support the expected growth of traffic, protect the ecosystem of the area, and solve the problems of limited parking spaces and safe access points. The light weight of the FRP solution allows workers to meet the construction requirements on uneven slopes in the area (more information on Composite Advantage’s Tahoe East Shore Trail project).
FRP piles. Composite Advantage’s piles have a high strength-to-weight ratio and can reduce the number of piles required in marine structures. CW Photo | Scott Francis
In addition to the bridge deck, Composite Advantage’s products also include composite piles and fender systems to repair aging waterfront infrastructure, including a bridge at the seaside resort on the southern end of Cape May Peninsula in New Jersey.
Reeve said: “We can make piles with a high strength-to-weight ratio, which means that we can make structurally very effective piles.” In the Cape May Peninsula project, the company’s FiberPILE FRP system was able to transform the structure required The number of piles is reduced by half, thereby saving costs. Composite Advantage used 53 composite piles to meet the necessary 250 kip feet of energy to absorb the impact load and eventually replaced 141 original wooden piles (see Composite Advantage’s Cape May Project).
Pull the floor. AIT Bridges’ composite arch system is covered with pultruded fiberglass decorative panels using a polyurethane matrix. Source | AIT Bridge
The composite arch system of AIT Bridges was developed at the Advanced Structure and Composite Center of the University of Maine (Orono, Maine, USA). Since its launch in 2008, it has been used to build more than 25 mid-span overloaded bridges. Braided fiber reinforced polymer (FRP) pipes, filled with concrete, are used as support structures for bridge structures with spans up to 80 feet. By providing a weather-resistant, non-corrosive outer layer, FRP provides concrete with a form that remains intact, and provides reinforcement and protection from elements for the exterior. On the vault is the main support member, and then covered with FRP floor pultruded with polyurethane resin. The company’s lightweight Atlas floor panels can be manufactured in any length and can be connected to composite arches with self-tapping screws and support backfilling.
Composite basin beam. In addition to being used for bridges, AIT Bridges’ CT girder systems can also be used for parking garages, floors and roof terraces, and other construction applications. Source | AIT Bridge
AIT Bridges has been developed in the past three years together with the Advanced Structure and Composite Center of the University of Maine. The latest innovation of AIT Bridges is its composite barrel (CT) beam system, which consists of U-shaped FRP beams supported by U-shaped FRP beams. On the standard foundation, and covered with prefabricated parts or prefabricated parts. Cast-in-place concrete bridge deck. The depth and width of the girder can be customized to meet the requirements of the project site; the maximum length is 120 feet.
Ken Sweeney, President and Chief Engineer of AIT Bridges, said: “One of the advantages of using composite materials is that you don’t have to be closely associated with very specific standardized designs and architectures.” “For steel and concrete, you will be It is troubled by strength and mechanical properties. Using composite materials, you can design the content that meets the requirements of specific projects on the architecture. This is one of the greatest values ​​obtained by using composite materials.”
In addition to being used for bridges and highway overpasses, the girder can also be used for parking lots, floors and roof terraces, and other construction applications. AIT Bridges’ first CT box girder bridge will be built in Hampton, Maine in 2020 (learn more about AIT Bridges’ CT box girder bridge system).
The company has also developed a mobile composite manufacturing unit (MCMU) that can be placed on a bridge site and used to manufacture parts on site. This 20-foot fully equipped manufacturing cell is equipped with all the tools and equipment required for manufacturing, enabling local and scalable manufacturing at low capital costs. These devices can be assembled and transported worldwide.
One of the exciting things about making advanced materials more accessible to infrastructure projects is that it is raising awareness that all advanced and traditional materials require higher standards. As the discussion shifts from the initial cost of advanced materials to the overall value of these materials, taking into account the time and labor saved during construction due to lightweight, and the long-term cost savings due to lower maintenance and maintenance costs. The service life of the structure, and more fair and objective considerations when selecting materials for infrastructure projects are taking place frequently. In addition, new innovative technologies are continuously improving the cycle time and efficiency of composite material processing, making it stand out from the competition.
“We hope that we can not only start to set the standards by which others must grow by building something that lasts longer, we hope to be able to do this and prove that we can also do it in the first place. The basis for cost competition.” Svoboda said . “This will really put pressure on everyone to strengthen their games, provide taxpayers with long-term solutions, and provide longer-lasting and better products.”
The matrix binds the fiber-reinforced material, gives the composite component its shape, and determines its surface quality. The composite matrix can be polymer, ceramic, metal or carbon. This is a selection guide.
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CMC is lightweight, hard and stable at high temperatures, and has entered commercial applications after more than 20 years of research and development.

Post time: Mar-20-2021
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