As new I-35W bridge opens, other Mississippi River bridge projects designed

On May 17, the Postal Service issued a new stamp honoring the Minnesota's sesquicentennial with a silhouette of the Mississippi River near Winona — prominently featuring the Highway 43 bridge in the foreground. A scant 18 days later, the Minnesota Department of Transportation (MnDOT) closed that same bridge for several weeks, citing safety concerns. For many, that juxtaposition captured perfectly the current moment in Minnesota's discussions about bridge infrastructure.

It's been just over 13 months since the I-35W span stunned us with its tragic fall into Mississippi River. In the wake of that bridge disaster, concern over Minnesota bridges has spread among public officials finally finding reasons to pay attention to our aging infrastructure.

And the replacement of these bridges brings with it an unprecedented chance to redesign the landscape of Mississippi River bridges in the Metro region. At least five bridges over the Mississippi River in the metro area are the focus of efforts for redesign and replacement.

Hastings Bridge

Among the first bridges to be checked after the I-35W tragedy was the U.S. 61 bridge over the Mississippi and into downtown Hastings. Following inspections, it was determined the bridge was in dire need of replacement. The bridge was temporarily upgraded this summer to hold up a few more years until a new Hastings bridge is slated to open.

The U.S. 61 bridge into downtown Hastings has long played a vital role in the City's sense of place as a river town. So much so, in fact, that the City's logo includes a rendering of the former bridge at that site.

From 1895 to 1951, the iconic Hastings spiral bridge was the gateway into Hastings. And the bridge was exactly what the name suggests. On the eastern end of the bridge, cars drove in a unique parking-ramp-like 360° spiral to bring commuters from the bridge deck into downtown Hastings below.

The new bridge, like the one it's replacing, won't include a spiral for cars. But one improvement the bridge will bring is a new 12-foot trail on its east side that will weave together existing and planned bike and pedestrian trails in the area. And to honor the bridge's history, designers are seriously considering the inclusion of a new pedestrian spiral on the bridge's eastern side in downtown.

A final design hasn't yet been selected, but a few alternatives remain - some that would roughly mimic the current bridge's general design, and others that would minimize the above-bridge superstructure. Construction on the new bridge is slated to begin in 2010.

Lafayette Bridge

Over a half-mile long, and built without structural redundancy, Saint Paul's Lafayette Bridge has long been slated for replacement. Construction on the bridge is now slated to begin in 2011, with a 2012 completion for a northbound span, and a 2014 completion for a southbound span.

A community advisory panel made up of Downtown, West Side, and other government leaders is working to shape the design of the bridge. That specific design has not been fully decided, but height requirements from boats below and airplanes above have tightly prescribed a narrow space in which the bridge could be built. One likely option seems to be a concrete box girder design — generally akin to the City's Wabasha Street Bridge.

One thing is certain: the new bridge will have substantially fewer supports than the old bridge had. That's important, because the City of Saint Paul has long been interested in redeveloping the area under the downtown side of the bridge as an extension of the Lowertown neighborhood. Fewer supports means fewer interruptions in the new neighborhood.

Perhaps the most significant improvement people hope to see in a new Lafayette Bridge is a bike and pedestrian connection on the bridge. Tim Griffin, Director of the Saint Paul on the Mississippi Design Center, believes if the bridge is designed well, it can help add another set of options for bikes and pedestrians to loop around Saint Paul's riverfront. Both Saint Paul and Minneapolis have capitalized on the creation of pedestrian loops around the riverfront as a key way to draw residents back to the river.

And the bridge brings other important elements. The bridge itself will tie together access to five existing bike and pedestrian trails — the Vento, Gateway, Sam Morgan, Lilydale, and Battle Creek trails.

Project staff have heard loud and clear about the need for bike and pedestrian access, and responded in kind. "A bike and pedestrian crossing seems like a pretty sure thing," said Dave Hall, a MnDOT staffer who has headed up a visual quality team working on the bridge. Hall says the crossing is likely to be on the east side, facing toward the bluffs at Mounds Park. On the west side of the bridge, engineers are also working to plan around a possible future light rail extension along the Lafayette Freeway that could be built next to the bridge.

The Shadow over the I-35W Bridge

Still to this day, the twisted rusty green remains of the I-35W bridge sit neatly catalogued on the west bank of the Mississippi River in an area known as Bohemian Flats. And 70 feet directly above, another chapter in Mississippi River bridgedom literally casts its shadow over what remains of that old I-35W bridge.

Minneapolis' two-tiered Washington Avenue Bridge is the primary connection between the University of Minnesota's East Bank and West Bank campuses. The lower deck transports tens of thousands of bus and car passengers each day, while the upper deck transports thousands of bicyclists and pedestrians. In August, the University of Minnesota announced the upper pedestrian deck - built to hold occasional trucks as well as bikes and pedestrians - could only safely hold bikes and pedestrians walking along the centerline of the bridge, and not near the edges.

Like the I-35W bridge, the Washington Avenue Bridge was built without redundancy - meaning that any failure could cause wholesale structural failure. And critically, as planning for the Central Corridor light rail line progressed, it has become increasingly evident that the bridge would need tens of millions of dollars in upgrades just to support the 53-ton LRT vehicles slated to begin crossing in 2014.

What this all means for the future of the Washington Avenue Bridge is far from clear at this point - the tens of millions of dollars in upgrades quickly begin to approach the cost of a full replacement of the bridge. Stay tuned as a tight light rail budget begins to raise serious questions about the lifespan of this increasingly derelict bridge.

I-35W Bridge Opens

Which brings us back to the bridge that first reopened our state's eyes to its crumbling infrastructure: the I-35W bridge over the Mississippi River. Enabled by an aggressive approach of designing the bridge as construction progresses, the new 35W span is set to open this week.

The bridge effectively acts as the eastern bookend of the Minneapolis Central Riverfront District, and as such, design became especially important. The basic design creates a sleek white bridge that will blend into its vibrant surroundings rather than become an icon on its own.

The bridge design also works to acknowledge its place on an historic stretch of the Mississippi river. Entry on the bridge will also be marked by 30-foot-tall river-like elements in the center medians. And instead of the typical concrete wall along the edge, the bridge includes an "open rail" design that will allow cars passing over the bridge a fuller view of the river and downtown environs.

When the new I-35W bridge opens this week, it will mark the end of a tragic chapter in Minnesota history. But the social and political impact of the loss of that bridge will be making their mark up and down the Mississippi River through the metro area for years to come.