A new, wider I-35W bridge over Minnehaha Creek will include a 10-foot-tall transparent wall - preserving the view for drivers but keeping sound out of the neighborhood - according to plans presented by the Minnesota Department of Transportation (Mn/DOT) and its consultants.
The bridge would be part of the Crosstown Commons project, which widens I-35W from three lanes in each direction to five lanes each way between 42nd and 66th streets.
At Minnehaha Creek, the new bridge will be 20 feet wider on each side than the current bridge to accommodate the added lanes, said SRF Consulting Vice President S. Rick Brown. The bridge's gap between opposite lanes of traffic will widen from the current 8 feet to 14 feet, allowing more natural light under the bridge.
Based on that layout, Brown presented a conceptual bridge design to the Minneapolis Park and Recreation Board's Planning Committee May 4. The Committee gave preliminary design approval but asked to review final plans.
The transparent wall could be built with Paraglass or other material, he said. Mn/DOT recommended the wall in response to neighborhood concerns about noise and light.
Commissioner Rochelle Berry Graves said a walking and biking path passed under the bridge and said she wanted to discourage homeless people from sleeping there. Brown said engineers had heard similar concerns from the neighborhood and designed the bridge with vertical abutments, which eliminate slopping areas under the bridges.
The design "created less area for people to be - and not be seen," he said.
The design includes lights under the bridge, which are both decorative and to illuminate the area, Brown said.
Board President Jon Olson had sharp questions for Mn/DOT about the lighting, noting the state had failed to maintain lights it installed under the freeway near Webber Park, 4400 Dupont Ave. N.
John Griffith, a Mn/DOT engineer, said it would be best to create an agreement with the city and Park Board wherein the state would reimburse the locals for light maintenance.
Underneath the bridge, a bike path runs next to the creek. Park staff calls it a safety issue, and the type of railing or fence that would get built to prevent bikers from inadvertently veering into the creek is unresolved. Brown asked the Park Board for comments.
The Crosstown Commons project is expected to start in 2006 and take four years to complete. Brown said he anticipated the Minnehaha Creek Bridge would be built earlier in the four-year cycle.
Brown said none of the new freeway runoff would go directly into the creek. It would go into Diamond Lake first, just as it does now.