The recovery of remaining victims and the increasingly unstable wreckage will complicate and slow the massive cleanup effort, for which a St. Paul contractor has been hired, officials said.
The massive job of removing bridge debris and smashed cars from the site of the collapsed Interstate 35W bridge will begin today, authorities said Sunday, but a final report on the cause of the disaster will take longer than expected -- up to a year and a half -- because of challenges posed by the wreckage and the Mississippi River.
The announcement came as Minnesota Department of Transportation officials said that they had hired a St. Paul contractor for the cleanup, expected to cost up to $15 million.
As thousands surveyed the bridge wreckage Sunday from the reopened Stone Arch Bridge, searchers reported finding no new victims to add to the list of five confirmed dead, and Minneapolis police arrested five people for crossing police lines to take photographs of the collapsed bridge and to collect souvenirs. "We need to send a message," Capt. Mike Martin said.
National Transportation Safety Board investigators have concluded that the collapse Wednesday probably did not begin on the bridge's south end and will begin focusing today on the north side, he said.
The federal investigation is being slowed by the danger the wreckage poses to emergency workers and investigators, said Mark Rosenker, chairman of the NTSB, during a news conference near the disaster site.
The 19 federal investigators assigned to the case are being extremely cautious in their work, he said.
"The collapsed bridge continues to get weaker and weaker the longer it sits there, because the integrity is gone," Rosenker said.
The NTSB has given MnDOT permission to begin removing cars, debris and the superstructure, which will be closely examined to find the exact point where the collapse began, Rosenker said. MnDOT has hired Carl Bolander & Sons Co., of St. Paul, for the cleanup.
"It's going to be a slow, tedious process," said Terry Zoller, MnDOT's project manager for the debris removal. "It's not just a matter of taking pieces out and throwing them on a barge.
"The first priority will be recovery of the dead."
The work could involve dozens of workers and as many as four cranes and two barges, said Mike Koob of Wiss, Janney, Elstner, an Illinois-based forensics firm that is investigating the collapse for MnDOT.
"This is still a recovery effort ... and it will be focused on finding those who are missing," said Bob McFarlin, assistant to MnDOT Commissioner Carol Molnau.
NTSB investigators will use a sophisticated computer program, updated by a former University of Minnesota student, to try to figure out how the bridge failed, Rosenker said.
The agency has collected an extraordinary amount of data for its investigation, including weather records dating at least 40 years, as well as preliminary information from the construction company on the materials and equipment that were on the bridge at the time of the collapse.
Photos at the time show a sand pile, a tanker truck and a concrete mixer on the bridge.
Rosenker said the weather data could prove significant because it would indicate possible patterns of the bridge's expansion and contraction history. All of the information, including weights, weather data and construction history, will be run through the model.
Reports about bridge wobble
NTSB investigators also said they have interviewed the construction workers who were on the I-35W bridge at the time of the collapse. It is only the second time in almost a quarter of a century that a highway bridge in the United States has fallen without an immediate cause such as a earthquake or a collision.
Some workers said that the bridge had been wobbling unusually in the days before the collapse, according to Minneapolis police Sgt. Tim Hoeppner. With every layer of concrete that they removed, the bridge would wobble even more, they told him.
Rosenker would not address that issue, or go into specifics about reports that the bridge had poor inspection ratings, but he said that would be part of the investigation. "We're going to take a look at that," he said.
MnDOT's McFarlin referred questions about the possible wobble to the NTSB, saying that would be part of that agency's investigation. He later declined to comment on the wobble reports, saying he had no information on their credibility.
"We'll let the NTSB do that work and they'll assess those kinds of reports, and there are all kinds of reports about work on the bridge. We'll just have to wait for the inspectors to do their jobs," he said.
McFarlin also was asked about the number of lanes that the bridge had when it opened in 1967, and its traffic volume. The bridge has been expanded at least once -- from six to eight lanes -- and there are indications that traffic on the bridge has almost quadrupled. In the past few years, the bridge has averaged more than 140,000 vehicles a day. He promised more specifics today.
It has been estimated that a new bridge will cost upward of $200 million, and McFarlin said that MnDOT will be facing a severe cash flow problem in the coming months even with the promise of more than $250 million in federal aid.
As a result, it's possible that some current and proposed MnDOT road projects could be suspended, delayed or canceled. "We hope it doesn't happen," he said.
McFarlin also said that a memorial to the victims at the new bridge has been mentioned and will continue to be discussed.
Getting a better look
Responding to public pressure for better viewing of the site, police reopened the Stone Arch Bridge on Sunday to pedestrians and bicyclists and said they planned to reduce the area off-limits to the public by early this morning. They also are considering reopening the 10th Avenue bridge adjacent to the I-35W bridge.
The Stone Arch Bridge had been closed since Wednesday night, when thousands gathered there to watch the disaster scene just downriver. Onlookers streamed onto the span when it reopened at 1 p.m. Sunday, and an hour later some spots along its south rail were three deep with spectators craning for a glimpse.
But police lost their patience with gawkers who crossed police lines to get closer to the collapsed bridge. While violators previously had been reprimanded, on Sunday police began to arrest them, Martin said. "We've decided we'd had enough," he said at an afternoon news conference.
Martin said he expects those arrested will be charged with interfering with a death scene, a gross misdemeanor that is punishable by a year in jail and a fine of up to $3,000.
Also Sunday, police took two busloads of reporters and photographers onto the 10th Avenue bridge for an up-close look of the collapsed bridge, about 100 yards to the west of the bridge.
Each of the seven disabled sections has its own story to tell. In some places, the span fell flat; in others, it twisted to one side or fell at one end, leaving a steep slope with vehicles clinging to the pavement.
A handful of workers prowled the wreckage, while a few others floated nearby in boats. Some men in orange hardhats probed the water with long poles. A duck floated near a Coast Guard cutter.
Police tape fluttered at every trail, path, road and parking lot in a broad arc around the fallen bridge. Dozens of officers stood watch.
To the west, looking back at the them, thousands could be seen lining the Stone Arch Bridge.
Staff writers Jim Foti and Rochelle Olson contributed to this report.