Every year, selected bridges across the United States receive a tune-up: repainting, deck patching, repairing structural components that show wear. It’ s routine.
That regular maintenance becomes less routine, however, when the bridge is one of the few routes over a major waterway, extends 1.5 miles, serves a region with a short construction season, and at 100-plus feet over the waterway, is subject to high winds.
Those were among the challenges the Wisconsin Department of Transportation( WisDOT) faced as the department considered how to best rehabilitate the Richard I. Bong Memorial Bridge, one of two bridges spanning the St. Louis River and Harbor to link Superior, Wisconsin, and Duluth, Minnesota. Ayres Associates designed the rehabilitation and provided the plans used by contractors over the two-year construction project.
It was a return“ home” for Ayres. WisDOT designed the bridge’ s steel tied arch span; Ayres designed the rest of the structure. The bridge opened to traffic in October 1985 and is still one of the largest public works projects undertaken by the State of Wisconsin. But after serving the region for nearly 30 years, it needed maintenance.
“ There were deficiencies identified by our bridge engineer,” said Matt Dickenson, the WisDOT project manager.“ The entire surface of the deck, over the course of salting the roadway for all those years, was showing some changes. The arch needed paint; the paint only lasts so long. We were beginning to see some rust on components.”
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