Bridge safety official seeks to calm

Though inspections rate more than 70,000 bridges nationwide structurally deficient, a top transportation official Friday called the deadly failure of a Mississippi River bridge an "anomaly" and said motorists shouldn't fear for their safety.

"I don't believe that they should be worried at all," National Transportation Safety Board Chairman Mark Rosenker said while visiting the bridge wreckage in Minneapolis.

Rules in place for 30 years "have improved the conditions and the standards that in fact these things are being inspected on," he said. "But with that said, as a result of this catastrophic disaster, we're going to be looking at the rules and finding out in fact if they should be tightened, made more stringent."

Rosenker's remarks came as Congress pushed to make $250 million available to Minnesota to cope with the bridge failure. Both houses planned to vote before the August recess.

The Minneapolis bridge was found structurally deficient in 1990. Transportation Secretary Mary Peters, asked Friday whether she could be sure none of the other structurally deficient bridges are unsound, said there are no indications that substantive changes in bridge inspections are needed.

Repairing all spans rated structurally deficient would take at least a generation and cost more than $188 billion - at least $9.4 billion a year over 20 years, according to the American Society of Civil Engineers.

Rosenker said it's too soon to know if the Minnesota collapse could have been avoided: "This is an anomaly and we're going to try to find out why this is an anomaly and prevent that anomaly from ever happening again," he said on ABC's "Good Morning America" Friday.

It is unclear how many of the structurally deficient bridges pose danger. Federal officials told states late Thursday to immediately inspect all bridges similar to the span that collapsed.

At least 73,533 of roughly 607,363 bridges in the nation, or about 12 percent, were classified as "structurally deficient," including some built as recently as the early 1990s, according to 2006 statistics from the Federal Highway Administration.

A bridge is typically judged structurally deficient if heavy trucks are banned or there are other weight restrictions, if it needs immediate work to stay open or if it is closed. In any case, such a bridge is considered in need of substantial maintenance, rehabilitation or even replacement.

The Federal Highway Administration has said addressing the backlog of needed bridge repairs would take at least $55 billion. That was five years ago, with expectations of more deficiencies to come.

It is money that Congress, the federal government and the states have so far been unable or unwilling to spend.

"We're not doing what the engineers are saying we need to be doing," said Gregory Cohen, president of the American Highway Users Alliance, an advocacy group representing a wide range of motorists. Cohen said engineers estimate $75 billion a year is needed just to keep highways and bridges from further deterioration, but that only around $60 billion a year is being provided.

The federal government provides 80 percent of the money for construction, repair and maintenance of the so-called federal-aid highway system including Interstate highways and bridges. But states set priorities and handle construction and maintenance contracts.

The federal government is now providing about $40 billion a year to improve and expand the nation's highways and bridges.

The main source of revenue for roads and bridges, the federal highway trust fund, is failing to keep up with spending demand. The 18.3 cents a gallon in federal taxes hasn't changed since 1993, and the demand for more fuel-efficient vehicles could affect fuel consumption.

Transportation Secretary Mary Peters said in an interview with The Associated Press that she had asked her department's inspector general to evaluate the agency's overall bridge inspections.

According to the Federal Highway Administration, most bridges in the U.S. Highway Bridge Inventory - 83 percent - are inspected every two years. About 12 percent, those in bad shape, are inspected annually, and 5 percent, those in very good shape, every four years.

The Department of Transportation's inspector general last year criticized the Highway Administration's oversight of interstate bridges. The March 2006 report said investigators found incorrect or outdated maximum weight calculations and weight limit postings in the National Bridge Inventory and in states' bridge databases and said the problems could pose safety hazards. The Highway Administration agreed that improvements in its oversight of state bridge inspections and data were needed.

Incorrect load ratings could endanger bridges by allowing heavier vehicles to cross than should, and could affect whether a bridge is properly identified as structurally deficient in the first place, the inspector general said.

The audit didn't identify any Minnesota bridges or mention the state beyond noting that 3 percent of its bridges were structurally deficient, placing it at the low end among states. It said those bridges were crossed by an average of 30,000 to 40,000 vehicles a day, putting it 13th among the states.

An analysis of 2006 Federal Highway Administration data found that Minnesota bridges were generally in better shape than those in other states. Only about 6 percent of the state's 20,000 bridges were listed as being structurally deficient. In Oklahoma, nearly 27 percent of bridges were cited by the federal government as being structurally deficient, the highest percentage among the states.

Among counties with more than 100 bridges, the problem appears to be most significant in the Midwest. In Nemaha County in southeastern Nebraska, about 58 percent of 194 bridges are structurally deficient. More than 55 percent of neighboring Pawnee County's 188 bridges are in the same shape. Of the 10 worst-off counties with significant numbers of bridges, seven are in Oklahoma or Nebraska.

On the other end of the scale, at least 10 counties with a significant number of bridges have none that are structurally deficient, according to the latest government statistics. A half-dozen of those are in Texas.

Several governors on Wednesday ordered state transportation officials to inspect particular bridges or review their inspection procedures.

Beyond Minnesota, North Dakota Gov. John Hoeven said his state doesn't have any bridges similar to the Minneapolis bridge but he had asked state officials to review inspection procedures. Presidential hopeful and New Mexico Gov. Bill Richardson ordered an inspection of several steel-truss bridges in the state. Arizona Gov. Janet Napolitano directed state transportation officials to conduct a statewide review, starting with highly traveled bridges in urban areas.

A police officer walks up the collapsed Interstate 35W bridge in Minneapolis on Thursday, Aug. 2, 2007. The bridge collapsed into the Mississippi River during Wednesday evening rush hour traffic.

Inspectors examine the collapsed Interstate 35W bridge in Minneapolis on Thursday, Aug. 2, 2007. The bridge collapsed into the Mississippi River during Wednesday evening rush hour traffic.

In a front page story in today’s Ft. Worth Star-Telegram, it was reported that there are 24 deficient bridges in Tarrant Co. alone. One was built in 1913 and carries about 12,000 vehicles a day, many of them huge 18 wheelers. Another was built in 1914 and carries 14,000 vehicles/day. These bridges over the Trinity River were made for model-Ts and horsedrawn carriages. We are insane to think that 80 year old bridges won’t come down. I dare say anything we build today won’t last that long.
And by the way, every county in Texas has a “Bridges and Roads Tax” that is paid with every vehicle license tag every year. Where is that money going?

OK, Here’s my theory.

The truss design is somewhat flimsy, it has been corroding for 40 years, there were stress cracks in several places.

It was hot, over 90 deg, so the bridge was near it’s upper expansion limit.

The bridge was designed for a loading of 40,000 cars a day, in recent years it had been handling over three times it’s designed load.

The outer lanes of the bridge overhang the support pillars.

At the time of the failure, only two lanes were in use but were tightly packed with slow, nose to tail, traffic which means the pounds per square foot loading on the lanes outside the support pillars was at the maximum you could achieve and there was nothing to balance that load laterally across the extent of the bridge.

I think that caused the road to shear, either the pillar collapsed sideways, or the roadway collapsed. If you look at the section where the school bus is, there is a longitudinal break in the roadway, parallel to the lane markings, with the outside lanes sagging about 15 degrees below the rest of the roadway.

Once the approach section collapsed, the adjacent truss supports were out of balance and the main span collapsed, and the far section also collapsed on itself (away from the river) because the main span had detached itself and thrown that truss also into an imbalance situation.

But then, I’m not a structual engineer..

“I don’t believe that they should be worried at all,” National Transportation Safety Board Chairman Mark Rosenker said ...I beg to differ...You sound like a government bureaucrat!...Like I should believe you??? It’s about time democrats and republicans got off their P.C. asses and started doing ONE of the jobs they were elected to do...MAINTAIN THE COUNTRIES INFRASTRUCTURE! Obviously the National Transportation Safety Board is smoking dope! I know allocating money for roads and bridges isn’t as glamorous as declaring war on global warming or aids. Get your heads out of your A@#$*!!

There’s plenty of money for infrastructure.....if the politico’s would quit FORCING LIGHT RAIL ON US! Washington State will be held hostage by Light Rail this year....with the bureaucrats making us vote on a bill that includes $30 billion for light rail with something like 18 billion for roads/bridges......they NEED to be SEPARATED, but, NOOOOO....

And by the way, every county in Texas has a “Bridges and Roads Tax” that is paid with every vehicle license tag every year. Where is that money going?

From the way I understand it, all State collected revenue for roads and bridges goes straight to the Federal government where Congress takes a huge cut off the top for 'general revenue.' Then, the remainder is given to all states if the state in question adheres to required Federal mandates.

So basically, your state tag tax is spent by the Congress-critters on whatever they want while they send back a much smaller IOU to your state for maintaining bridges and highways.

BTW - this is how Congress blackmailed the central states into adopting the 55 mph national speed limit. Congress refused to give back any of the road money until the states (like Nebraska) passed 55mph legislation....even though the money was Nebraska's to begin with.

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