Bridges Under Scrutiny As Minn. Mourns

With as many as 30 people still missing following Wednesday evening's catastrophic bridge collapse, families are braced for further news as the recovery effort continues in the murky waters of the Mississippi. Laura Bush will visit the scene today and meet with victims and victims' families.

As divers search the river for submerged vehicles and bodies trapped beneath the twisted debris of the I-35W bridge, finger-pointing has already begun over a federal report two years ago that found the bridge was "structurally deficient."

Several teams of investigators are examining the evidence on what may have caused the eight-lane Interstate 35W bridge to buckle and collapse.

"It's hard to be conclusive so early, but it looks like the main support, the main steel arch, may have given way or something right near it," Richard Stehly, an expert in bridge engineering and co-founder of St. Paul, Minn.-based American Engineering Testing, told CBS Evening News anchor Katie Couric.

"Also, the things that support the main arch, the foundations on either bank, perhaps they did. But investigators will look at everything. They will look at the materials. They will look at all the pieces of debris. And they'll find out the cause, because we need to learn the reason for its failure."

Inspections as far back as 2000 on the bridge identified both corrosion in the steel and a lot of cracking, says Stehly.

Questions are also being raised about a 2005 report in the U.S. Department of Transportation's National Bridge Inventory that rated the bridge as "structurally deficient" and possibly in need of replacement.

The report said there were fatigued details on the main truss and floor truss system. Yet it concluded there was no need to prematurely replace the bridge because of fatigue cracking, avoiding the high cost associated with such a large project.

When the bridge was built 40 years ago, it was state of the art, a massive steel arch spanning the Mississippi. But the bridge was designed without the extra support common to later designs, which meant that if one component failed, the whole bridge was likely to fall, reported CBS station WCCO-TV in Minneapolis.

Federal officials alerted states Thursday to immediately inspect all bridges similar to the Minneapolis bridge that collapsed.

President Bush, who will travel to the scene of the disaster on Saturday, said the federal government would help rebuild the bridge in the city that will host next year's Republican National Convention.

"We in the federal government must respond, and respond robustly, to help the people there not only recover, but to make sure that lifeline of activity — that bridge — gets rebuilt as quickly as possible," Mr. Bush said.

Still stung by harsh criticism of the government's sluggish response to Hurricane Katrina, Mr. Bush talked with state and local officials in Minnesota, and the administration dispatched officials to the scene.

The House Transportation Committee quickly approved legislation Thursday that would direct $250 million to Minnesota to help it replace the bridge.

The White House said a U.S. inspection of the 40-year-old bridge in 2005 found problems. The Interstate 35W span rated 50 on a scale of 100 for structural stability and was classified as "structurally deficient," transportation officials said.

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. "It didn't mean that the bridge is unsafe," Transportation Secretary Mary Peters said.

Earlier, at the White House, press secretary Tony Snow said while the inspection did not indicate the bridge was at risk of failing, "If an inspection report identifies deficiencies, the state is responsible for taking corrective actions."

Minnesota Gov. Tim Pawlenty on Thursday ordered 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 no call by anyone that we're aware of that said it should be immediately closed or immediately replaced," Pawlenty said. "It was more of a monitor, inspect, maintain, and potentially replace it in the future."

The eight-lane Interstate 35W bridge, a major Minneapolis artery, was in the midst of repairs when it buckled during the evening rush hour. Dozens of cars plummeted 60 feetinto the Mississippi River, some falling on top one of another. A school bus sat on the angled concrete.

A strong current and low visibility hampered the search for bodies, but at least four submerged vehicles had been located with sonar, officials said.

The divers face extreme danger — they have to avoid mountains of twisted steel, concrete and cars. The massive debris field has created pockets of fast-moving water, small whirlpools that could pull a diver to his death, reports CBS News correspondent Byron Pitts.

"We have a number of vehicles that are underneath big pieces of concrete, and we do know we have some people in those vehicles," Dolan said. "We know we do have more casualties at the scene."

Speaking with Couric on Thursday, Pawlenty said there were 80,000 bridges designated as "structurally deficient," adding that inspectors of the I-35W bridge "indicated there was no need for dramatic intervention."

As 2007 began, at least 73,694 of the nation's 596,808 bridges, or about 12 percent, were classified as "structurally deficient," Federal Highway Administration figures show. They include 816 built as recently as the early 1990s and 3,871 that are nearly a century old,

In the Mississippi River, divers took down license plate numbers for authorities to track down the vehicles' owners. Getting the vehicles out is expected to take several days and involve moving around very large, heavy pieces of bridge.

Relatives who could not find their loved ones at hospitals gathered in a hotel ballroom Thursday for any news, hoping for the best.

As many as 50 vehicles tumbled into the river when the bridge collapsed, leaving those who could escape to scramble to shore. Some survivors carried the injured up the river bank, while emergency workers tended to others on the ground and some jumped into the water to look for survivors. Fire and black smoke rose from the wreckage.

"People who were pinned or partly crushed told emergency workers to say 'hello' or say 'goodbye' to their loved ones," Dolan said.

The first step of the federal investigation will be to recover pieces of the bridge and reassemble them, much like a jigsaw puzzle, to try and determine what happened, NTSB Chairman Mark Rosenker said.

Investigators also want to review video of the collapse, and were setting up a phone number for witnesses to call with information.

"It is clearly much too early in the initial stages of this investigation to have any idea what happened," Rosenker said.

This week, road crews had been working on the bridge's joints, guard rails and lights, with lane closures overnight on Tuesday and Wednesday.

The steel-arched bridge, built in 1967, rose 64 feet above the river and stretched 1,900 feet across the water. It was built with a single 458-foot-long steel arch to avoid the need for piers that might interfere with river navigation.