Posted on 08/02/2007 7:47:03 PM PDT by NormsRevenge
MINNEAPOLIS - Minnesota officials were warned as early as 1990 that the bridge that collapsed into the Mississippi River was "structurally deficient," yet they relied on patchwork repairs and stepped-up inspections that unraveled amid a thunderous plunge of concrete and automobiles.
"We thought we had done all we could," state bridge engineer Dan Dorgan told reporters not far from the mangled remains of the span. "Obviously something went terribly wrong."
Questions about the cause of the collapse and whether it could have been prevented arose Thursday as authorities shifted from rescue efforts to a grim recovery operation, searching for bodies that may be hidden beneath the river's swirling currents.
The official death count from Wednesday's rush-hour collapse stood at four, with another 79 injuries. But police said the death count would surely grow because bodies had been spotted in the water and as many as 30 people were still reported missing.
The Army Corps of Engineers lowered the river level a foot to help recovery efforts, said agency spokeswoman Shannon Bauer.
In 1990, the federal government gave the I-35W bridge a rating of "structurally deficient," citing significant corrosion in its bearings. The bridge is one of about 77,000 bridges in that category nationwide, 1,160 in Minnesota alone.
The designation means some portions of the bridge needed to be scheduled for repair or replacement, and it was on a schedule for inspection every two years.
Dorgan said the bearings could not have been repaired without jacking up the entire deck of the bridge. Because the bearings were not sliding, inspectors concluded the corrosion was not a major issue.
During the 1990s, later inspections found fatigue cracks and corrosion in the steel around the bridge's joints. Those problems were repaired. Starting in 1993, the state said, the bridge was inspected annually instead of every other year.
A 2005 federal inspection also rated the bridge structurally deficient, giving it a 50 on a scale of 100 for structural stability.
White House press secretary Tony Snow said while the inspection didn't indicate the bridge was at risk of failing, "if an inspection report identifies deficiencies, the state is responsible for taking corrective actions."
Gov. Tim Pawlenty responded Thursday by ordering an immediate inspection of all bridges in the state with similar designs, but said the state was never warned that the bridge needed to be closed or immediately repaired.
"There was a view that the bridge was ultimately and eventually going to need to be replaced," he said. "But it appears from the information that we have available that a timeline for that was not immediate or imminent, but more in the future."
Federal officials alerted states to immediately inspect all bridges similar to the one that collapsed.
The eight-lane Interstate 35W bridge was Minnesota's busiest bridge, carrying 141,000 vehicles a day. It was in the midst of mostly repaving repairs when it buckled during the evening rush hour. Dozens of cars plummeted more than 60 feet into the Mississippi River, some falling on top one of another. A school bus sat on the angled concrete.
Engineers wondered whether heavy traffic might have contributed to the collapse. Studies of the bridge have raised concern about cracks caused by metal fatigue.
"I think everybody is looking at fatigue right now," said Kent Harries, an assistant professor of civil and environmental engineering in the University of Pittsburgh's School of Engineering. "This is an interstate bridge that sees a lot of truck traffic."
After a study raised concern about cracks, the state was given two alternatives: Add steel plates to reinforce critical parts or conduct a thorough inspection of certain areas to see if there were additional cracks. They chose the inspection route, beginning that examination in May.
Dorgan said officials considered the cracks on parts of the bridge to be stable and not expanding.
When conducting inspections, Dorgan said, inspectors get within an arm's length of various components of a bridge. If they spot cracks, that leads to more hands-on testing to determine the depth and extent of the fissures.
Although concern was raised about cracks, some experts theorized it's no coincidence the collapse happened when workers and heavy equipment was on the bridge. The construction work involved resurfacing and maintenance on guardrails and lights, among other repairs.
"I would be stunned if this didn't have something to do with the construction project," said David Schulz, director of the Infrastrucure Tecchnology Institute at Northwestern University. "I think it's a major factor."
The collapsed bridge's last full inspection was completed June 15, 2006. The report shows previous inspectors' notations of fatigue cracks in the spans approaching the river, including one 4 feet long that was reinforced with bolted plates. A 1993 entry noted 3,000 feet of cracks in the surface of the bridge; they were later sealed.
That inspection and one a year earlier raised no immediate concerns about the bridge, which wasn't a candidate for replacement until 2020.
In a 2001 report from the University of Minnesota's Department of Civil Engineering, inspectors found some girders had become distorted. Engineers also saw evidence of fatigue on trusses and said the bridge might collapse if part of the truss gave way under the eight-lane freeway.
"A bridge of that vintage you always have to be concerned about that," said Richard Sause, director of the Advanced Technology for Large Structural Systems Center at Lehigh University. "In a steel bridge of that age, sure you'd be concerned about those kind of things and be diligent about looking after it. And it seems like they were."
It takes time for a fatigue crack to develop, but a crack can then expand rapidly to become a fracture, said James Garrett, co-director of the Center for Sensed Critical Infrastructure Research at Carnegie Mellon University. "If you get a crack that goes undetected it would be something that appears to happen more rapidly."
At the scene, about 15 divers and a dozen boats were in the water, but the search was proceeding slowly because of strong currents and low visibility. By mid-afternoon, they had located four submerged cars besides the dozen or so visible from the surface.
"We have a number of vehicles that are underneath big pieces of concrete, and we do know we have some people in those vehicles," Police Chief Tim Dolan said. "We know we do have more casualties at the scene."
Meanwhile, relatives who couldn't find their loved ones at hospitals gathered in a hotel ballroom for any news, hoping for the best.
Ronald Engebretsen, 57, spent the day searching for his wife, Sherry. His daughter last heard from her when she left work Wednesday in downtown Minneapolis. Afterward, her cell phone picked up only with voice mail.
By Thursday evening, the Hennepin County Medical Examiner's Office announced that Sherry Engebretsen was confirmed dead. The other three were Julia Blackhawk, 32, of Savage; Patrick Holmes, 36, of Moundsview; and Artemio Trinidad-Mena, 29, of Minneapolis.
In brief telephone interview, Ronald Engebretsen said he and his family had huddled to try to come to grips with his wife's death.
"She's a great person. She's a person of great conviction, great integrity, great honesty and great faith in her God," he said. "We're just hoping and praying here."
___
Associated Press writers Seth Borenstein, Martiga Lohn, Ryan Foley and Jon Krawczynski contributed to this report.
How did George Bush manage to get Bill Clinton not to give any money for this bridge to be repaired when he wasn’t even president yet?
He and Rove are amazing!
Prayers of comfort and strength go out to those who lost family members and those who also await news of those unaccounted for or listed as missing.
Built poorly by lazy union members.
Good question.
I was just gonna post the link to this thread on the
Jack Cafferty Just Blamed Bush For Minn Bridge Colapse
http://www.freerepublic.com/focus/f-news/1875475/posts
But Minnesota has the money to build a stadium for a billionaire - Carl Pohlad.
I hope the wacko baseball fans enjoy their stadium with our money that could have been used for infrastructure.
They all need to get a life instead of watching overpaid men that play children’s games very well for a billionaire owner.
I guess Bush will be blamed for this one too.
The moral of this story is:
It takes a lot of finger pointing before someone’s ass gets handed to them. Musical chairs anyone.....?
They keep using those words. I do not think they mean what they think they do.
Real reason is probably 40 years of NaCl on the roadway to control ice and snow. Corrision of steel to steel connections IMO will be the majority reason for the failure.
I have been told not to drive on a particular bridge in Washington DC.
wonder if they have used the quote, “good enough for government work” before.
It is interesting that the Romans built bridges that have lasted for 1500 years, with technology that was considered antiquated, BUT the high-tech geniuses that are being produced in today’s colleges can only design a bridge that will last for 40 years!!!!
Prove your posted “Statement”.
So it is George H. W. Bush’s fault?
Time to fire back.
I hate how this is shaping up. When was the last time a bridge collapsed killing a lot of people? I can’t remember, but I sure as hell don’t remember even thinking to blame the president, whoever it was. I just don’t understand why leftists aren’t laughed at 24/7 for blaming republicans everytime something bad happens.
‘last for 40 years’
NOT the Mackinac!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.