Minnesota picks preliminary design for bridge to replace fallen span

Bridge plans
Plans for a new I-35W bridge over the Mississippi River in Minneapolis were displayed at the Minneapolis City Council.
MPR Photo/Brandt Williams

The aerial sketch is simple. It shows two side-by-side bridges that will each hold five lanes of traffic running in opposite directions over the Mississippi River. The old 35W bridge had four lanes in each direction.

"The previous bridge was around 100 feet (wide). So there is more width to these bridges and along with that more lane capacity and more shoulder capacity," according to John Chiglo, MnDOT's project manager.

Chiglo says they will not begin building the bridge until all of the missing bodies from the bridge collapse have been recovered.

Many of the design details will be left up to the five firms bidding to land the contract. The bridge is expected to cost between $200 and $250 million.

MnDOT officials hope to finish the bridge by the end of 2008, that's a much faster pace than the years it typically takes to go from blueprint to ribbon cutting. But they say they've been busy talking with federal and state transportation officials who operated under similar time constraints.

"I think what we really learned is confidence," said Bob McFarlin, special assistant to the transportation commissioner. He says they talked with transportation officials in Oklahoma and California on what is needed to speed up the construction process. He says state and federal officials told them that they can finish the job quickly and safely, mostly because they can waive some state and federal red tape that slows a project down.

"We are confident with the experiences that other states have had that this can be done," he said. "It can be done quickly and safely and with really good quality because they had that experience."

McFarlin says he doesn't see any potential drawbacks to an accelerated bridge build. He says the contractor will use a design/build standard in which the design of the bridge occurs at the same time as the bridge is being built.

Hassan Astaneh, a professor of engineering at the University of California Berkeley, says the public shouldn't be concerned that an accelerated construction process would discount safety. He says states and contractors have nearly perfected the so-called design/build process in the past decade.

At this point, Astaneh he says it doesn't make a difference if a contractor takes their time or builds the bridge on an accelerated basis

"All of it is really to optimize your construction methods not to change design code, which is the document that you use for design and issues of safety. So I can't see any reason why people should think that if you do it fast that it will not be as safe as if you build it slowly," he said.

It could take weeks before the public will get more specifics, such as whether the bridge will be built of concrete or steel. MnDOT officials say they will consider public input throughout the process, even after a contractor is selected in September.

That's a step back from Monday's briefing where a spokeswoman suggested the public would have limited input on the final design. That upset some state lawmakers and Minneapolis officials who say MnDOT was moving too quickly. They suggested greater public input was needed on the bridge.

The first of those meetings was Tuesday morning at Minneapolis City Hall. MnDOT officials briefed a City Council committee. Some members wanted to know the timeline. Others, like Don Samuels, wanted the bridge to be a memorial for those who died in the collapse.

"The observation from all points is going to be significant and should really be considered," he said.

City officials, including Mayor R.T. Rybak, want the bridge to be able to handle an expansion of the light-rail system.

Last week MnDoT commissioner Carol Molnau and Metropolitan Council Chairman Peter Bell said "no."

It now appears MnDOT is willing to consider the idea.

McFarlin said it would involve changing traffic lanes to light-rail lanes. He also pointed out that the federal emergency bridge replacement money for the new span comes with strings attached. It allows spending only for replacing the bridge that collapsed and not a span with added features.

Money for a new bridge built to specifications that could accommodate future transit, he says, would need to come from other sources, either local or state or other federal funds.

Also, McFarlin warns, building a new bridge strong enough to handle some future transit option such as rail might require use of heavy construction equipment that could trigger environemental reviews and delay construction.

Delay is what worries Metropolitan Council Chairman Peter Bell. He says the risk of delay associated with even planning for accommodating a future light-rail line is not a good idea.

"At a minimum that would be a two- to three-month delay and most people believe strongly that an interstate highway is not a good place for transit," according to Bell.

Minneapolis elected officials, including Mayor R. T. Rybak have been lobbying state officials with the message it's prudent to take the extra planning time to consider building a new span that can accommodate future transit needs since the new bridge is expected to last 100 years.

"If we build this bridge without looking at the possibility of reinforcing the structure for light rail at a future date, then it means that within a week's time people have excluded light rail in that corridor, be it Central, be it 35W be it anywhere else in that area for an entire generation. That is a rush to judgment," Rybak said.

The Minnesota Center for Environmental Advocacy's director of land and transportation planning, Jim Erkel, says the reason it makes sense to plan for a new bridge that could accommodate transit is the projected growth in volume of commuters and other traffic on a new span.

"That corridor is probably one of the most high-volume corridors that we have," he said. "When you look at the various levels of transit, it makes more sense that this corridor be run with light rail than with BRT."

BRT is bus rapid transit. Several state and regional officials including the Metropolitan Council's Bell, say that's the future transit option that fits best on a new 35W bridge span.

Bus rapid transit, its advocates argue, is cheaper and more flexible than light rail. At the moment, however, the new 35W bridge is not part of any of the Met Council's planned bus rapid transit routes.

"It is not and we would have to look at is it a viable corridor but next year we are doing our 10-year transit plan and that is something that we will look at very closely," Bell said Tuesday.

The rapidly evolving debate over how the new 35W span should be built reveals several things about Minnesota's transportation picture.

One is MnDoT's abililty to respond to ideas for what a new bridge should include is limited. Virtually all the agency's funds are spoken for. The failure by lawmakers and the governor last session to agree on a transportation funding bill severely limits MnDoT's financial flexibility.

The debate also reveals the hunger among transit advocates for an opening that allows them to advance their message the region is transit starved.

Winning agreement on how to proceed with a fast track bridge replacement process while trying to accommodate future transit focuses attention on the philosophical divide between those who favor roads and bridges and those who favor rail and buses.