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The state of Maine has a history of implementing historic, innovative solutions across the state’s infrastructure system. Maintaining transportation infrastructure is an ongoing battle for state DOTs as many bridges across the nation are in constant need of repair or replacement. In an effort to minimize project impacts and maximize their return on infrastructure investments, MaineDOT utilized numerous innovative technologies and strategies including composite bridges and beams.  

Unlike traditional bridge materials like concrete and steel, composite materials offer the advantages of durability and corrosion resistance resulting in low maintenance and long service life.  

Composite Girders Extend Life of Maine Bridge 

In early 2021, Maine Department of Transportation (MaineDOT) — in partnership with Advanced Infrastructure Technologies (AIT) Bridges — announced the completion of the newly constructed Grist Mill Bridge making it the first in the nation to utilize AIT’s corrosion-resistant composite GBeam technology. AIT Bridges is a subdivision of AIT, a global transportation management leader 
that specializes in designing and supplying composite bridge systems and other structural materials.  

Located in Hampden, ME, the newly constructed, 75-ft single span Grist Mill Bridge is composed of five AIT composite beams manufactured at a nearby AIT facility. This composite bridge, and other innovations like hybrid composite bridge girder systems, deliver cost effective, durable bridge solutions that extend the service life of new bridges for the next 100 years. The GBeam technology used on the project was developed in accordance with the University of Maine’s Advanced Structures and Composites Center (UMaine ASCC). 

The former Grist Mill Bridge, which was constructed in 1950, was comprised of three separate bridges stacked one on top of the other. After more than 70 years of exposure to the elements, the bridge suffered from severe concrete deterioration. 

The new structure is the first in the nation to use — what AIT refers to as — composite turb girders. Instead of conventional concrete reinforcement, the turb girders are comprised of fiberglass reinforced polymers (FRPs). According to MaineDOT, these FRP composites do not rust or deteriorate the same way traditional bridge materials do.  

“Our composite tub girder is, ultimately, going to be a game changer in the bridge construction sector,” said Chairman and CEO of AIT Bridges, Brit Svoboda, “It is versatile, strong but lightweight, affordable, and ultimately intended to replace concrete and steel girders in the marketplace. For anyone that knows of our arch system, this is a natural extension of what we already offer. It can be used as a highway, rail, or pedestrian bridge, even as part of a building structure, parking garage system, marine structure, and in many other places where steel and concrete support girders are used.” 

Maine’s Success with Composite Materials  

MaineDOT’s success with composite materials goes back more than a decade. In 2010, MaineDOT, in collaboration with UMaine Advanced Structures & Composites Center (AEWC) and the Maine Composites Alliance, created, tested and executed multiple composite solutions. Together, they implemented emerging composite bridge technologies that paved the way for years to come.  

One of those innovative solutions was the Bridge-in-a-Backpack, a composite arch bridge system filled with concrete. Developed at UMaine’s AEWC Advanced Structures and Composites Center, this technology was commercialized by AIT and implemented across other cities throughout the state. Another technology that the agency and university collaborated on is a composite culvert-lining system. These liners provide an alternative to traditional concrete liners for culvert rehabilitation. 

InfraTalk America’s Publisher, Gregory Nadeau, served seven years at the Maine Department of Transportation (MaineDOT). Before his time as the Federal Highway Administration (FHWA) Administrator, Nadeau served as MaineDOT’s deputy commissioner for policy, planning and communications. In this role, he was responsible for state and federal policy, and he was involved in multiple statewide economic development initiatives. For several years, Nadeau oversaw the state’s transportation system planning, freight and business services and passenger transportation. 

 “My MaineDOT service very much catalyzed my passion for transportation infrastructure innovation that I carried with me to Washington D.C. during my eight years at the FHWA. MaineDOT clearly leads the nation in expanding the use of sustainable composite bridge technology,” stated Nadeau. 


FHWA, MaineDOT, AIT, UMaine 

2020 Maine Infrastructure Report Card