PITTSFIELD, Maine — The 35-foot-long Neal Bridge on Route 11 in central Maine is the first in the nation to use a process developed at the University of Maine that is dubbed “bridge in a backpack” because the materials used to make the arches can be carried to the site in duffel bags.
Once at the site, a light, durable fabric that folds as easily as a pair of pants is filled with concrete to form arches that will support the span. They’re installed in days or even hours, instead of weeks. The process is being touted as a way to cut costs and lengthen the life expectancy of bridges.
University workers put together 23 fabric arches that were cut to a pattern, inflated and coated with resin to retain their shape, said Habib Dagher, director of the university’s Advanced Structures and Composites Center. They were then taken to the site, put into place and filled with concrete — all in a day.
The fabric is made of composite materials, often a blend of carbon or glass fibers, which reduce construction time and costs, Dagher said.
“Instead of having problems in 20 years, you won’t have problems until 40 years,” Dagher said. “This could be 100-plus years of performance.”
