Legalectric

Slowly it’s coming out… today it’s the New York Times:

Potential flaw seen in design of bridge

 By MONICA DAVEY and MATTHEW L. WALD

MINNEAPOLIS, Aug. 8 — Investigators have found what may be a design flaw in the bridge that collapsed here a week ago, in the steel parts that connect girders, raising safety concerns for other bridges around the country, federal officials said on Wednesday.

The Federal Highway Administration swiftly responded by urging all states to take extra care with how much weight they place on bridges of any design when sending construction crews to work on them. Crews were doing work on the deck of the Interstate 35W bridge here when it gave way, hurling rush-hour traffic into the Mississippi River and killing at least five people.

The National Transportation Safety Board’s investigation is months from completion, and officials in Washington said they were still working to confirm the design flaw in the so-called gusset plates and what, if any, role they had in the collapse.

Still, in making public their suspicion about a flaw, the investigators were signaling they considered it a potentially crucial discovery and also a safety concern for other bridges. Gusset plates are used in the construction of many bridges, not just those with a similar design to the one here.

“Given the questions being raised by the N.T.S.B., it is vital that states remain mindful of the extra weight construction projects place on bridges,” Secretary of Transportation Mary E. Peters said in a statement issued late Wednesday.

Since the collapse, the concern among investigators has focused on “fracture critical” bridges, which can collapse if even a single part fails. But neither the safety board nor the federal Department of Transportation on Wednesday singled out any particular design of bridge in raising its new concerns about gusset plates and the weight of construction equipment.

Concerns about the plates emerged not from the waters of the Mississippi River here, where workers have only begun to remove cars and the wreckage with cranes, but from scrutiny of the vast design records related to the steel truss bridge.

In Minneapolis, state transportation department officials seemed surprised by the sudden focus on the bridge’s gusset plates, which are the steel connectors used to hold together the girders on the truss of a bridge. On this bridge, completed in 1967, there would have been hundreds of them, officials here said.

Gary Peterson, the state’s assistant bridge engineer, said he knew of no questions that had ever been raised about the gusset plates, no unique qualities to distinguish them from those on other bridges, no inkling of any problem during decades of inspections of the bridge.

“I don’t know what this could be,” Mr. Peterson said. “I’m frankly surprised at this point. I can’t even begin to speculate.”

If those who designed the bridge in 1964 miscalculated the loads and used metal parts that were too weak for the job, it would recast the national debate that has emerged since the collapse a week ago, about whether enough attention has been paid to maintenance, and raises the possibility that the bridge was structurally deficient from the day it opened. It does not explain, however, why the bridge stood for 40 years before collapsing.

In an announcement, the safety board said its investigators were “verifying the loads and stresses” on the plates as well as checking what they were made of and how strong they were.

State authorities here said the plates were made of steel, and were, in most such bridges, shaped like squares, five feet by five feet, and a half inch thick. Such plates are common in bridges as a way to attach several girders together, said Jan Achenbach, an expert in testing metals at the Northwestern University Center for Quality Engineering and Failure Prevention.

A consultant hired by the State of Minnesota in the days after the collapse to conduct an investigation of what had gone wrong, even as the national safety board did its work, first discovered the potential flaw, the board said. Representatives at Wiss, Janney, Elstner Associates Inc., the consulting firm, could not be reached late Wednesday.

Federal authorities said one added stress on the gusset plates may have been the weight of construction equipment and nearly 100 tons of gravel on the bridge, where maintenance work was proceeding when the collapse occurred. A construction crew had removed part of the deck with 45-pound jackhammers, in preparation for replacing the two-inch top layer, and that may also have altered the stresses on the bridge, some experts said.

The chairman of the National Transportation Safety Board, Mark V. Rosenker, said on Sunday that investigators were calculating the stresses generated on each girder and other bridge components from the construction equipment and materials.

While cautioning states on Wednesday about the weight of construction equipment and materials, the federal transportation department did not immediately issue any broader warnings about gusset plates. Brian Turmail, a spokesman for the Transportation Department, said on Wednesday evening that his agency was “conducting additional analysis to determine whether we need to ask the states to do checks of their designs.”

If there was a design error in the 1960s, failure to identify it before the bridge collapse indicates a problem with the federal inspection program, said Thomas M. Downs, who was the associate administrator of the Federal Highway Administration from 1978 to 1980.

Here, state officials were racing to respond to the new concerns about a design flaw, but said they had no details. “We’re going to leave that to the N.T.S.B.,” said Bob McFarlin, assistant to the commissioner of the Minnesota Department of Transportation.

Of a potential design flaw, Brian McClung, the spokesman for Gov. Tim Pawlenty, said the state’s transportation department “will be looking into every single issue and possibility raised by the N.T.S.B. or the parallel investigation ordered by Governor Pawlenty, including this one.”

Mr. Peterson said that concerns about gusset plates might normally focus on questions of corrosion over time, but that he had never heard of a question over the original design or metal make up of a plate here. Had ultrasonic testing of the plates shown signs of corrosion or cracking, that would be a concern, he said. But in the case of the I-35W bridge, Mr. Peterson said he recalled “no gusset plate issues at all.”

When the bridge was built, in the 1960s, its hundreds of gusset plates were attached with rivets, though bridge designers here switched to bolts, a stronger option, in the 1970s.

“Bolts are better,” Mr. Peterson said, “but we wouldn’t consider anything wrong with rivets.”

Monica Davey reported from Minneapolis, and Matthew L. Wald from Washington.

.

WTF? I don’t know. I sat there for two days, listened to arguments that required waders, I spouted off occasionally, and was witness to the most nonsensical non-decision I’ve ever seen. What is it? What does it mean? I don’t know. We’ll know more when the formal written Order comes out, but the gist is:

1) The Mesaba Project was found, contrary to the ALJs’s Recommendation, that it IS an Innovative Energy Project; and

2) It is NOT in the public interest; and

3) Excelsior and Xcel are supposed to go back to the table (yeah, right…); and

4) the PUC is going to strong arm other utilities to get together and support an IGCC project in Minnesota.

More later after I finish up with 20 pages of notes from yesterday…

Here’re some photos that arrived in the inbox earlier today:

Click here — Bridge collapse – Tim Davis – Consolidated Photo

Both Gov. Tim Pawlenty and Sen. Norm Coleman are quoted saying the bridge had been inspected and was fine, no problems… but that’s not what the DOT’s bridge inspection reports said…
Daily Kos has links to the bridge reports HERE.

STrib graphic of bridge.

From the New York Times:

Bridge collapse kills at least 7

August 2, 2007

By LIBBY SANDER and SUSAN SAULNY

An Interstate highway bridge in downtown Minneapolis loaded with rush-hour traffic dropped more than 60 feet into the Mississippi River last night, sending at least 50 vehicles and passengers into the water.

Chief Jim Clack of the Minneapolis Fire Department said at least 7 people were killed and more than 60 were injured. The Star Tribune of Minneapolis reported that 9 were dead, 20 were missing and 60 were injured.

Chief Clack said that most of the rescues were made within an hour of the collapse and that 22 of the city’s 26 fire engines responded to the scene. Fire departments from surrounding communities also responded.

“This is a catastrophe of historic proportions for Minnesota,” Gov. Tim Pawlenty said at a news conference about three hours after the collapse.

The eight-lane bridge on Interstate 35W, the main north-south route through Minneapolis, was being repaired at the time, and a witness told MSNBC that he had heard a jackhammer being used on the roadway just before the collapse about 6 p.m. Witnesses said the bridge, which was built in 1967, collapsed in three sections. One section of the bridge lay flat in the river, with cars parked on the rolling pavement.

The collapsed bridge, which was about 1,000 feet long, had been supported by a steel truss structure. Repairs were being made to the bridge’s concrete deck, guard rails and lights, state officials said.

The construction work was being done by Progressive Contractors Inc. of St. Michael, Minn. Tom Sloan, the company’s vice president for bridges, told KARE 11 television that 18 workers were on the bridge at the time of the collapse and by about 10 p.m. 17 of them had been accounted for.

Divers and rescue boats continued to search the river and the twisted wreckage of the bridge as darkness set in and rain began to fall. The Star Tribune said some people were seen floundering in the river, calling for help. The search efforts were suspended about midnight and will resume at daylight.

Leah R. Fulin, 16, of Minneapolis, had just crossed the bridge and was on the Washington Avenue exit when it collapsed behind her.

“Most of the cars that were on the bridge went into the river,” she said. “There was a whole bunch of smoke when concrete breaks like that. There were people screaming.”

Janet Stately was returning from Duluth, Minn., and had decided to take an adjacent bridge to avoid traffic when the collapse occurred.

“I heard an awful noise and saw what looked to me like a piece of the freeway just going down flat,” Ms. Stately said. Then she said she saw the road collapse into a V and cars rolling into the river. “I clearly recall horns honking. I was screaming. We were trying to call 911 on our cellphones.”

Television stations showed a school bus on one section of the collapsed slab, but the back door was open and no passengers were visible. Red Cross officials said 60 children were taken off the bus, 10 of whom had injuries that were treated at city hospitals. A column of smoke curled up from a tractor-trailer near the bus.

“I saw a lot of crying,” Courtney Johnson of the Red Cross told CNN. “Some of the older children were comforting the younger children.” The children were 4 to 12 or 13 years in age, Ms. Johnson estimated.

Berndt Toivonen, 51, of Minneapolis, told The Star Tribune he had been on his way home from a painting job when the bridge collapsed beneath his car.

“The bridge started to buckle,” Mr. Toivonen said. “It went up and it came down. I thought I was going to die.” He was uninjured, but he said people around him, some injured, were screaming in their cars. He told MSNBC that he helped some other people off the bridge.

Dr. Joseph Clinton, chief of emergency medicine at Hennepin County Medical Center, said six patients at the hospital had critical injuries and 22 had injuries that were not considered life threatening. There was one drowning fatality, Dr. Clinton said.

“This is a very busy bridge,” said Senator Amy Klobuchar, Democrat of Minnesota, whose home is nearby. “It’s really right in the heart of the city,” Ms. Klobuchar told CNN. “Thousands of commuters use this bridge every day.”

According to the Minnesota Department of Transportation, the flow on the eight lanes of I-35W crossing the river was supposed to be restricted beginning Tuesday night for the northbound lanes and at 8 last night, about two hours after the collapse, for the southbound lanes. The reason stated on the agency’s Web site was “overlay work,” which refers to roadway resurfacing.

A 2001 evaluation of the bridge, prepared for the state transportation department by the University of Minnesota Civil Engineering Department, reported that there were preliminary signs of fatigue on the steel truss section under the roadway but no cracking.

It said there was no need for the transportation department to replace the bridge because of fatigue cracking.

Governor Pawlenty said the bridge had an unusual design and was inspected in 2005 and 2006. No structural deficiencies were detected, he said.

Senator Norm Coleman, Republican of Minnesota, told CNN that the bridge had received a “clean bill of health” three years ago. Mr. Coleman said the work on the bridge was a resurfacing project, not uncommon in Minnesota in the summer.

The Minnesota Twins, who play home games in the Metrodome not far from the site of the bridge collapse, had a moment of silence before their game Wednesday night. Team officials decided to play Wednesday’s game after public safety officials decided that sending 20,000 to 25,000 people back into traffic could hinder rescue efforts, the Twins’ president, Dave St. Peter, told The Associated Press. Today’s game against the Kansas City Royals has been postponed, along with a groundbreaking ceremony for a new baseball stadium, according to the Twins Web site.

Cellphones in the area were disrupted after the collapse, possibly because antennas were overloaded with calls. As the toll of the injured and missing rose, a woman who was near the scene of the collapse called a cable network desperate for information: “If Janna or Paul hear grandma’s voice, please call home,” she begged.

The National Transportation Safety Board will send a team of investigators, a spokesman, Ted Lopatkiewicz, said. The board chairman, Mark Rosenker, will accompany the investigators, Mr. Lopatkiewicz said.

Pat Borzi, Jason Skog and Carla Baranauckas contributed reporting.

========================

Out of time — a Motion to crank out then off to the PUC…