Lawmakers impressed by progress on 35W bridge

MINNEAPOLIS -- Minnesota lawmakers stood atop the 10th Avenue Bridge in Minneapolis Tuesday and watched as workers hoisted a 170-ton segment of new I-35W bridge into place.

"It's remarkable, absolutely phenomenal," remarked Senator Steve Murphy, the Red Wing Democrat who heads the Senate Transportation Committee, "In the future I think this is going to be a case study in how to build transportation infrastructure in cold weather environments."

Members of Murphy's committee joined their counterparts from the House for a tour of the construction site above the Mississippi River. As the people who approve major highway budgets they have more than a passing interest in the subject of an extremely high profile $234 million work in project.

"As a worker what's even more impressive is they don't have any lost-time work injuries, and very few minor injuries," Murphy said.

Most lawmakers were naturally curious about how the 504-foot center span, suspended over the river, will support itself once the two sides meet in the middle.

"It's nice that MnDOT is telling us all the details," Senator Michael Jungbauer, a Republican from East Bethel told KARE, "It's pretty fabulous when they're explaining how they anchor and put all these pieces together and how it all works."

Defies gravity

Project engineer Jon Chiglo played the role of the pied piper at times, as lawmakers followed him along the pedestrian and bike path on the bridge that runs parallel to the construction site.

"If you'll notice the sight lines have been improved on the north approach here," Chiglo told his lawmaker tourists, "And in the profile you'll see the crest of the bridge is about in the center, which will make drainage much better."

But most of the questions Chiglo and fellow engineers fielded involved the elaborate system of interlocking sections, connecting rods and cables that will anchor the pre-cast concrete segments of the arch to the river banks.

The general contractor, Flatiron-Manson, is installing the box girder sections at a pace of four a day. They've already connected 60, so it should take 15 days to install the final 60.

Those "building blocks" will grow from each side until the converge in the center to form the main arches.

"There's a gap that's still left, so the segments don't actually touch," explained deputy project engineer Terry Ward, "We'll push them apart, set up closure forms, and pour concrete into that space."

And while the main body of the bridge, the superstructure as it's known, will be in place within three weeks there's a lot more to be done. Flatiron-Manson expects to open it to traffic by Christmas Eve, if not sooner.

The voice of experience

The chairman of the House transportation panel, Representative Bernie Lieder, was also impressed by what he saw Tuesday.

"I think you have to say it's pretty well coordinated when you have that type of construction, that many people, that many different operations going on its really well coordinated," Lieder told KARE.

"It's a real good operation. There's no doubt about it."

His opinion isn't to be taken lightly. The Crookston Democrat is a retired engineer who erected many bridges in his career, including several nearly as long as this 1,223-foot bridge.

They're all still standing. And yet none look like what's rising from the banks of the Mississippi in downtown Minneapolis.

"The way their strands are tied, they block them, so you're never going to see the whole works drop at one time if something does happen," Lieder told KARE.

"The design type lends itself to safety really."

He said Flatiron-Manson's speed will surprise many in the industry, because concrete box girder spans typically take longer to build than steel bridges with beams. "The other bidders went with a steel design because they asumed it would be finished more quickly."

MnDOT Responds to consultant

The old 35W bridge fell during rush hour on August 1st of 2007 killing 13 people and injuring at least 140 others. At times the tragedy brought politicians together, but at other times it seemed to pull them apart.

While the actual cause of the collapse remains under investigation by the National Transportation Safety Board, the event became political because it exposed MnDOT's funding shortfalls to public and legislative scrutiny.

"I think it taught the legislature something too, that we have to be concerned about funding," Representative Lieder asserted.

"There was no way the Department of Transportation could program a bridge, schedule one for construction, because that would've taken away most of their construction funds for one year."

MnDOT has insisted from the start, however, that money was never a factor in decision-making about how to repair problems detected in the I-35W Bridge by inspectors and paid engineering consultants who studied it for years prior to the accident.

The head of the agency took exception to the words, "Funding considerations influenced decisions about the Bridge" found in the report from Gray Plant Mooty, the law firm hired by lawmakers to study MnDOT's decision-making process leading up to the collapse. In a letter to lawmakers, Transportation Commissioner Tom Sorel insisted that MnDOT has never allowed financial issues to compromise the agency's commitment to public safety.

He said the Wakota Bridge in South Saint Paul, Lafayette Bridge in Saint Paul and Dresbach Bridge in Winona were all higher priorities for replacement than the 35-W bridge last year, knowing what MnDOT knew at the time.

Sorel added, "Those decisions on priorities were, of course, made without knowledge of the fatal design flaw present in the I-35W Bridge's gusset plates."

The NTSB has already come to the conclusion that those steel gusset plates, which serve as connection joints for the trusses, were under designed for a bridge of that size. The steel plates weren't thick enough, according to investigators, to sustain the weight added to the 1967 bridge over time.

Many of the same lawmakers on touring the bridge site Tuesday met at the Capitol later to hear MnDOT's response to the advice offered in the Gray Plant Mooty report.

One recommendation was that MnDOT do annual inspections of all fracture-critical bridges, but supervising bridge engineer Dan Dorgan told the panel that wouldn't be practical.

"If we're asked to do annual in-depth inspections for all bridges statewide that are fracture critical," Dorgan told the committee, "We will end up diverting resources from those bridges that we think need more frequent inspection to some that are probably of lesser concern."

Dorgan said there are 230 fracture critical bridges in Minnesota, 70 on the MnDOT's trunk highway system and 160 on the local roads. Some have very low volume traffic, ranging from five to 20 vehicles per day.

By John Croman, KARE 11 News

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