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The 3-D laser scan allowed engineers to look at the bridge even after it was dismantled (O.N.E.)

Laser scanning technology helped a Minnesota bridge find its third home

One of 24 historic bridges chosen for preservation by the Minnesota Department of Transportation, Bridge 5721 is one of the state’s only remaining wrought iron bridge structures. The bridge was originally built to carry pedestrians over a river in Sauk Center, Minnesota, in 1870, before modern steel production methods had become available. In 1937, the bridge was disassembled and moved to span the Little Fork River near the town of Silverdale. But more than two years ago, the structure began its journey to a third incarnation, this time as an equestrian and pedestrian bridge for the Gateway Trail in the town of Stillwater, near Minneapolis. Because of the bridge’s provenance and the desire to keep its wrought iron parts intact, the Minnesota DOT worked with new owner Minnesota Department of Natural Resources and structural engineers at HNTB and Olson & Nesvold Engineers (O.N.E.) to collect crucial data for the rehabilitation using new 3-D laser scanning technology.
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