ADVERTISEMENT

1bodyjh.112522.jpg

JERRY HOLT ¥jgholt@startribune.com 8/9/2007---Officials carry the body of victim up the embankment on the north side of the river around 12:30pm on Thursday. The body was taken of a boat and transported by the medical examiner. Bridge Collapse

Jerry Holt, Star Tribune

hausmann

Peter Hausmann, of Rosemount, was on the 35W bridge when it collapsed. His body was recovered from the river on Thursday.

Courtesy Assurity River Group,

Should this bridge be open?

  • Article by: Pam Louwagie, James Walsh and Paul McEnroe
  • Star Tribune
  • August 11, 2007 - 10:48 PM

Corroded strands of rebar jut from the sides and pillars of the cracked Hwy. 36 bridge near Stillwater, while jagged pieces of fallen concrete litter the ground below.

Every day, nearly 10,000 vehicles travel eastbound over the crumbling structure. Most of the people in the huge trucks, cars and school buses on the bridge are unaware that it has been listed federally as "basically intolerable."

The Hwy. 36 span, crossing over Hwy. 95, appears to be the only structurally deficient bridge on a major Twin Cities highway to carry such a critical label. But throughout Minnesota, hundreds of thousands of drivers cross over steadily deteriorating bridges. Many are considered to be in worse shape than the Interstate 35W span before its collapse and have been on replacement lists for years.

Taxpayers will have to spend a minimum of $1.4 billion over the next two decades to repair or replace the metro area's aging bridges, the Minnesota Department of Transportation estimates.

Deciding when bridges get repaired or replaced involves an array of complex factors including political battles over budgets, engineering assessments, and public outcries. Closing a bridge is rare.

State Sen. Kathy Saltzman, DFL-Woodbury, steamed Friday as she stood under the Hwy. 36 bridge, which is in her district, looking for the first time at its dilapidation.

"This is alarming," said Saltzman, a member of the Senate Transportation Committee. "You just don't want to drive across this bridge."

While the public finds federal labels such as "intolerable" and "deficient" alarming, experts downplay the public's perception of such terms and say they don't necessarily translate into a bridge being unsafe. "It is not a safety issue where the public needs to be concerned," said Dan Dorgan, the state's top bridge engineer.

Replacement is on hold

The Hwy. 36 bridge was scheduled to be torn down as part of a larger project to install a new bridge over the nearby St. Croix River. The new bridge has been stalled, so more repairs are being made to the Hwy. 36 bridge instead.

After the collapse of the Interstate 35W bridge in Minneapolis, John Sievert, a Republican constituent of Saltzman's, sent her photos of the bridge, which is a mile south of Stillwater. "This bridge is a disaster waiting to happen," he warned in his letter.

Until then, Saltzman said she was not aware of just how badly the bridge needed major repairs. "Who drives under a bridge looking up?" she asked.

An inspection report from July 2006 gave the bridge a sufficiency rating of 28.3 on a scale of zero to 100. A rating under 50 means a bridge needs monitoring, might need to be replaced and is eligible for federal replacement funding.

Saltzman called MnDot and learned that $733,000 worth of repairs -- including redecking, reinforcement bars and reconstruction of expansion bearings -- is scheduled to begin in September. Plans call for lane diversions and a temporary bypass. The work is expected to take about a month.

"I wonder what kind of phone calls the governor would get if this bridge was in his district," Saltzman said. "I'm wondering what kind of recommendations he could give me on how to proceed. Who do the people go to? Why didn't I know this? Why am I supposed to crawl under bridges to find out about such a bridge? Why should I trust these bridge ratings?"

Cayuga span carries more cars

The Cayuga Bridge in St. Paul, a 1,285-foot span of I-35E just north of downtown, is rated better than the Hwy. 36 bridge, but appears likely to be replaced sooner.

The bridge has been on replacement lists for years. It has a sufficiency rating of 40.8 and carries nearly 150,000 vehicles a day. Part of a bigger, $197 million I-35E improvement project from I-94 north to Maryland Av., Cayuga has nonetheless been on hold.

St. Paul city officials say the bridge was originally slated to be replaced in 2004. A MnDOT plan calls for replacement between 2015 and 2023, the same period during which the I-35W bridge was to be replaced.

Dorgan said that, unlike the I-35W bridge, Cayuga is not a fracture-critical bridge. It has redundant beams, meaning that the failure of one part would not necessarily lead to complete collapse. The main concern with Cayuga, he said, is the bridge's deck.

"The worst that can happen is you punch a hole in the deck and you have to shut a lane down," Dorgan said.

Why has the Cayuga not yet been replaced?

In a word, money. Five years ago Elwyn Tinklenberg, then MnDOT's commissioner, announced that 163 projects during the next decade would be deferred because of a lack of funds. One of those projects was the Cayuga bridge.

Across the country, the public is scrutinizing bridges' sufficiency ratings -- a federal highway administration measure for funding bridge projects. Not just a measure of safety, the ratings take into consideration factors such as the amount of traffic a bridge carries and the length that a detour would require.

"It's a composite of all kinds of different issues," Dorgan said, adding that a bridge with a lower sufficiency rating could actually be in better structural condition than one with a higher rating.

There's no point on the sufficiency scale that warns of imminent collapse, Dorgan said. If engineers determine that a bridge is unsafe, MnDOT would close it, he said.

Bridge inspectors look for deterioration by measuring metal thicknesses after corrosion, cracks and chips in concrete and cracks caused by metal fatigue. Inspectors who find cracks in key locations would call an inspection engineer and possibly shut the bridge down, Dorgan said.

As a bridge deteriorates, highway officials will restrict heavy loads from crossing it, he said. That may mean keeping extremely heavy trucks off first, and possibly all traffic later. In the meantime, transportation officials often plan for the bridge's repair or replacement.

Fracture-critical bridges are inspected more often and are watched more closely, Dorgan said.

Facing the heat

Closing a bridge can be an unpopular call.

Samuel Schwartz faced scorn from merchants, commuters and the mayor when, as chief engineer overseeing bridges in New York City in 1988, he closed the Williamsburg Bridge between Manhattan and Brooklyn.

"You have to have a lot of backbone," he said. "You're gonna catch both political heat and public heat."

It got so bad, he said, that he spent part of a day watching the scene in "To Kill a Mockingbird," where Gregory Peck wipes spit off his face instead of fighting back.

In Minnesota, when Richard Braun was transportation commissioner in 1984, he shut down the nearly century-old St. Paul High Bridge because nobody knew "when it might collapse into the Mississippi River," according to a newspaper report. The bridge was later replaced.

"To this day I have no idea how I had the guts to do this all by myself," Braun said.

Over the course of three or four years, Braun said, he was shown rusty steel plates and, one year, a rusty joint pin. Every time he went from the State Capitol to the airport, he drove under the bridge. It "raised doubts in my mind as to what we were doing," he said. "One day I just decided by myself that I was going to close the bridge."

There was no money set aside to replace it.

"I had no backing from anyone," Braun said.

He called a news conference and announced the closure.

"I really caught hell, especially from the restaurant owner south of the river," Braun said. The restaurant owner, he said, threatened to get a court order prohibiting the shutdown.

"I responded that I had given this some thought and felt it was a reasonable approach. ... The judge could do with it whatever he wanted, open it, close it, allow one-way traffic, metering the traffic," Braun said. "I could sleep a lot better at night."

Staff writers Laurie Blake and Dan Browning contributed to this report. Pam Louwagie • 612-673-7102 James Walsh • 651-298-1541 Paul McEnroe • 612-673-1745

© 2014 Star Tribune