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Fiber Reinforced Polymer Meets Modern Challenges

Fiber Reinforced Polymer Meets Modern Challenges

When Hurricane Sandy battered countries and states on the Atlantic in 2012, the United States was lucky to suffer no fatalities. Though no Americans died as a direct result of the storm, Sandy was the sixth-costliest hurricane in U.S. history and crippled many parts of the Atlantic coastline for weeks and sometimes months. Damage to transportation and infrastructure stalled the healing process for hard-hit places like New Jersey and New York.

Take the New York subway system’s Canarsie Tunnel. Sandy flooded 3,445 feet of the 7,953-foot-long tunnel, damaging or ruining tracks, signals, switches, power, communication cables, lighting, cable ducts, and bench walls. The $477 million repair contract called for demolition and reconstruction of 60,000 linear feet of duct banks; 14,400 linear feet of track and track bed; 270,000 linear feet of cable ducts and repair of 7,000 feet of concrete lining and installation of tunnel lighting and fire systems. Worst of all: the repair contract estimated that MTA would have to suspend the L-train for 15 to 18 months while these repairs took place.

New York couldn’t wait almost two years to recover from Hurricane Sandy. The city and the Metropolitan Transportation Authority (MTA) needed a solution that would repair the damage thoroughly, safely and much faster than 18 months. The best academic minds were consulted and recommended Fiber Reinforced Polymer (FRP) as the material of choice to speed up the process without sacrificing quality. The city then turned to Creative Composites Group (CCG) to source the needed solution: tunnel shrouds. Though they didn’t exist at the time, CCG worked with the New York City MTA and its engineering firm to deliver a trailblazing solution.

For rail platforms to utility poles to bulkheads and much more, FRP is the material of the moment, meeting the unprecedented challenges of the 2020s at the speed of business, even when that means inventing new uses for the material.

Innovation And Design Flexibility

Because FRP is a man-made material, it’s able to be changed and improved upon as new data and new demands arise. Creative Composites Group didn’t say, “FRP can’t do that” to the people of New York City. It was instead, “Let’s find a way.” 

FRP can meet an enormous variety of innovative needs due to its design flexibility. Take New York City’s first FiberSpan™ bridge deck for the West Thames Street pedestrian bridge. The prefabricated FRP decking traveled fully fabricated from Ohio to NYC in 2019. The 16-panel FRP deck features included curbs, access to utilities underneath and a long lasting, non-slip overlay of quartz aggregate polymer and is supported by a two-span steel lenticular truss bridge designed to meet performance requirements. These requirements included 90 PSF live load and a deflection rating of L/360. The deck area totals 3,482 square feet, with individual deck panel dimensions of 12.9 feet by 12.9 feet, a deck depth of 4 inches and a deck weight of only 8.4 PSF. 

This innovative, flexibly designed structure was installed in just one night while Manhattan slept. FRP’s light weight means it can be installed fast.

Light And Fast, But Durable

Comparing steel, concrete, wood, and FRP, a layperson might assume that the lightweight composite material couldn’t be as strong as the traditional materials. But FRP is high-strength and moderately stiff with the design flexibility to optimize for the desired structural properties.  The table below shows the strength-to-weight comparison of different construction materials; FRP’s low weight and high strength significantly reduces installation time and disruptions to transportation. The property combinations also give FRP a service life often much longer than traditional materials and consider utility poles. Designed to be somewhat flexible, FRP can endure a significant load during a major event and return to its normal state – unlike steel, which stays bent, or wood, which can snap. In addition, FRP poles can absorb about 10 times the energy of a steel pole with similar geometries, and unlike wood poles, FRP poles aren’t victim to the life-shortening effects of woodpeckers or termites.

And they’re light: A 40-foot Class 1 wood pole weighs in around 1,100 pounds and steel at 450. FRP is the lightest of the bunch, with a weight of 412 pounds. At less than half the weight of traditional wood poles, FRP utility poles can be installed faster, even over rough terrain, saving labor costs and reducing traffic disruptions. The durability and light weight of FRP poles also means poles may be transported in fewer loads compared to heavier, traditional materials, reducing the emissions produced in transport.

Smaller Carbon Footprint

When the Massachusetts Bay Transportation Authority (MBTA) needed new ramps and side platforms for the new Chelsea Station near Boston, FRP provided the attributes they sought. These lightweight FRP structures were easy to install – with each section of the platform taking only half an hour to secure, avoiding transportation disruptions. 

And like taking the train itself, using FRP reduced the overall environmental impact. FRP materials have lower embodied energy than other infrastructure materials since less energy and water is required in its manufacturing of the fibers, polymers and final structure. And CCG’s use of pultrusion and infusion are energy efficient fabrication processes. 

FRP also has a smaller lifetime footprint: Besides reducing transportation emissions, FRP’s resiliency gives it a very long service life with minimal maintenance. Harmful emissions are significantly reduced by materials that stay stronger for longer. 

Corrosion Resistance

All materials degrade, but not all materials degrade at the same rate. Traditionally, seaside bulkheads are made of concrete strengthened with steel rebar. But when exposed to salt water through the porous concrete, steel almost immediately begins to corrode and rust. Rusted steel weakens the concrete, creating cracks and the corrosion deterioration accelerates until the reinforced concrete must then be replaced, sometimes as frequently as every decade. This is a great and unnecessary expense.

FRP is inherently corrosion-resistant, warding off chemicals, salt and water for up to 100 years.  Several polymer types are available, each offering the right resistance to any type of chemical or environment exposure. For infrastructure applications, design flexibility allows these products to be tailored for flame retardants, temperature resistance, UV protection and higher corrosion resistance. These additives are easier and simpler to add to FRP versus traditional materials. FRP stands up to salt water without compromising its durability and requires little to no maintenance over its long service life.

FRP: The Material For Our Moment

From labor shortages to supply chain disruptions, the 2020s are presenting grave challenges to every sector of the economy. Fiber Reinforced Polymer infrastructural and transportation products made by Creative Composites Group are manufactured in the United States. Domestic-made means having the affordable supply needed to keep engineers’ projects moving at the speed of business with a material with the resilience to weather almost any condition. FRP products are already changing waterfronts, bridges, utility poles, cooling towers and much more around our country. And with its design flexibility, light weight, smaller footprint and corrosion resistance, we’re excited to see what else FRP can do for engineering transportation and infrastructure. 

To learn more about Creative Composites Group visit www.creativecompositesgroup.com.