Trends Summer 2016 - Page 8

could result from replacing the road surface. Like so many other things with this project, that work was far from routine. Most bridges are straight; their sides are parallel throughout. The Richard I. Bong Memorial Bridge is “S” shaped and the approaches are more complicated than most. “The load rating was complex because of this bridge’s unique alignment and flared geometrics,” Pantzlaff said. “The Minnesota approach in particular has complex geometry. We also performed a load rating for the arch itself. The tied arch is a unique structure; it behaves different structurally. The load rating got to be quite sophisticated. Our structural engineering analysis revealed that the bridge had plenty of capacity for vehicles, even after the additional load from the concrete deck overlay.” The project included milling off 2 inches of deck surface and overlaying the deck with new concrete. That’s 600,930 square feet of bridge decking – equivalent to more than 13 acres (or, for the sports-minded, more than 10 football fields). Crews repaired sidewalk edges, updated lighting, and repainted surfaces. A structure as large as the Richard I. Bong Memorial Bridge will expand and contract depending on temperatures, and the project included replacing the 24 sets of joints that accommodate those movements. The center span of the bridge is a 500-foot-long, 80-foothigh, steel tied arch. Each supporting cable in that span was inspected, repaired, and adjusted as needed – a fairly involved process, Pantzlaff noted. Improving intersections While crews were working on the bridge, another crew was improving the Wisconsin side approach. Ayres designed the 1.3 miles of approach, including realigning a portion of the highway that crosses the bridge – U.S. Highway 2 – with Belknap Street, a major thoroughfare in Superior. Ayres’ design work included design of a multilane roundabout at the intersection of U.S. Highway 2 and Belknap Street to replace several intersections. This roundabout is the first roundabout for the City of Superior. Mayor Bruce Hagen supported construction of the roundabout from the start. “Consider safety, cost, efficiency, and the maintenance of a signalized intersection as years go by,” he said. “I think it’s a wonderful addition to the community.” 8│TRENDS TRENDS │9