An aging infrastructure in the U.S. means that bridges and roadways need to be built or replaced at an accelerating rate
AIT has “de-engineered” bridges and produced a simpler, lighter, low-impact structure that takes advantage of natural elements
With a life expectancy of 100 years, the bridge will use fewer resources initially and across its lifespan
AIT’s bridge is a lightweight system that melds a traditional structural arch design with modern materials to create a complete bridge system that extends lifespan and reduces life cycle costs compared to existing alternatives. The company aims to improve infrastructure while minimizing resource use and impacts to the natural environment.
An aging infrastructure in the U.S. and growth in the developing world means that bridges and roadways need to be built or replaced at accelerating rate. AIT has “de-engineered” bridges and produced a lighter, sustainable, long-life, and low-maintenance structure. The bridge incorporates an arch shape, an inherently efficient structure taking advantage of natural elements, to produce a joint-free structure without the use of steel reinforcement. Additionally, the arches are rapidly deployable and do not require the heavy equipment or large crews needed to handle the weight of other construction materials. With a life expectancy of 100 years and limited maintenance, the bridge will outperform standard bridges designed to last 50-75 years. This new method of building bridges will reduce the negative effects of corrosion and consume fewer resources across its lifespan.
The bridge is the first composite concrete bridge of its kind to gain approval by AASHTO (American Association of State Highway and Transportation Officials). It represents the first innovation in concrete bridge designs in decades. The arch bridge is appropriate for bridges that span 75 feet or less, or approximately 75 percent of bridges in U.S. The technology has applications in culvert replacement, tunnel projects, as well as water management. The system has been widely tested with advanced structural characterization, predictive modeling, and fatigue testing, along with environmental durability tests for UV, fire, and abrasion resistance. There are 12 AIT arch bridges in service. While still in the early stages of rolling out the product, the system has received numerous awards, including the 2011 Award for Innovation from the American Society of Civil Engineers (ASCE).
While a lot has been done to develop and facilitate the construction of more sustainable buildings (e.g., LEED, Living Building Challenge), relatively little has been done for bridges – “horizontal buildings,” if you will. AIT is trying to change decades-old, resource-intensive habits in the particularly risk-averse field of engineering, while providing much-needed solutions to meet growing infrastructure needs with sustainable designs.
AIT has developed a more sustainable bridge design with a longer life that not only uses fewer materials in construction, but also does not require an on-going application of coatings and sealants, meaning it could make an entire product obsolete, saving all of the resources associated with it. This design also keeps structural elements out of waterways, so streambeds and aquatic life are left undisturbed. Overall, the company is focused on promoting simple, sustainable infrastructure solutions that can be easily adopted in many parts of the world.
The corrosion-free concrete arch bridge design began with a request to engineers at the University of Maine from the Natick Army Research Lab. The Army was interested in a lightweight structure that could be implemented easily in the field without the normal, lengthy engineering and design process, and could be left in place over time with little maintenance, providing a sustainable solution. The first bridge was constructed for the Maine Department of Transportation and was dubbed “bridge-in-a-backpack” because of the easily transportable input materials used by the system.