The Christian Science Monitor
Thursday 02 August 2007
About one-quarter of America's 577,000 bridges were rated deficient in 2004.
The tragic rush-hour collapse in Minneapolis of the I-35W Bridge over the Mississippi River is again forcing a reexamination of the nation's approach to maintaining and inspecting critical infrastructure.
According to engineers, the nation is spending only about two-thirds as much as it should be to keep dams, levees, highways, and bridges safe. The situation is more urgent now because many such structures were designed 40 or 50 years ago, before Americans were driving weighty SUVs and truckers were lugging tandem loads.
It all adds up to a poor grade: The American Society of Civil Engineers gave the nation a D in 2005, the latest report available, after assessing 12 categories of infrastructure ranging from rails and roads to wastewater treatment and dams.
"One of America's great assets is its infrastructure, but if you don't invest it deteriorates," says Patrick Natale, executive director of ASCE.
Among scores of recent examples:
- Last month, a 100-year-old steam pipe erupted in midtown Manhattan, killing one man and causing millions of dollars in lost business.
- The inadequacies of levees in New Orleans became horrifyingly clear in the aftermath of hurricane Katrina. The city is still recovering.
- In 2003, the Silver Lake Dam in Michigan failed, causing $100 million in damage.
America's 577,000 bridges are of particular concern because they are subject to corrosion. According to the website of Nondestructive Testing (NDT), which advocates not damaging structures during testing, the average lifespan of a bridge is about 70 years. Bridges are inspected visually every two years. However, NDT notes, "it is not uncommon for a fisherman, canoeist, and other passerby to alert officials to major damage that may have occurred between inspections."
In the federal government's rating system, any bridge that scores less than 80 – on a scale of 1 to 100 – is in need of rehabilitation. A bridge scoring below 50 should undergo reconstruction under federal guidelines. In 2004, 26.7 percent of US bridges, urban and rural, were rated deficient, down from 27.5 percent in 2002, according to the US Department of Transportation (DOT).
Minnesota's record is far better, with only 12.2 percent of its bridges falling into the deficient or obsolete categories.
Federal officials were quick to point out that those designations don't mean the bridges are unsafe.
"None of those ratings said there was any kind of danger," US Transportation Secretary Mary Peters said in Minneapolis on Thursday. The ratings are used to point out deficiencies or overhauls that need to be conducted in the future.
Most bridge collapses occur from an obvious cause: an earthquake or a barge running into bridge supports. On rare occasions, however, bridges have collapsed for less obvious reasons. In 1983 in Greenwich, Conn., the Mianus River Bridge collapsed, killing three people. A federal investigation blamed excessive accumulation of corrosion on a hangar pin, a key part of the bridge.
In the case of the Minneapolis bridge collapse, the National Transportation Safety Board will lead the investigation. Its investigators were also on the scene to begin to piece together what had caused the collapse.
"It is much too early in this investigation to know what happened," NTSB Chairman Mark Rosenker said Thursday. The first step is to reassemble the pieces of the bridge like a jigsaw puzzle to figure out what triggered the collapse, he said.
State inspection officials had inspected the bridge twice since the federal government rated the bridge "structurally deficient" but concluded the bridge was safe. State officials were in the process of completing a third inspection – interrupted because of construction on the bridge – when the bridge collapsed Wednesday afternoon at the height of rush hour.
As many as 30 people were missing as of press time Thursday.
Concerns about the bridge go back at least six years.
A 2001 report by the University of Minnesota, Department of Civil Engineering, stated, "Concern about fatigue cracking in the deck is heightened by a lack of redundancy in the main truss system. Only two planes of the main trusses support the eight lanes of traffic. The truss is determinate and the joints are theoretically pinned. Therefore, if one member were severed by a fatigue crack, that plane of the main truss would, theoretically, collapse."
This was a steel, arch-truss style bridge with a concrete deck that should have lasted at least 60 years, says P.K. Basu, a civil engineer at Vanderbilt University and an expert on bridge design and failure. Corrosion of rivet connections is a suspect, as are possible cracks around such joints. Some signs of structural failure due to corrosion are subtle, he says, and may only be discernible by experts. Increased weight of trucks in recent years could be another factor.
The bridge was part of Interstate 35, a major transportation link for Minneapolis, and one of the most heavily traveled urban highways in the country. It was also the first of its size in the US to be equipped with an anti-icing system that sprayed a de-icing element on the bridge deck.
President Bush on Thursday promised the federal government would respond "robustly" to help with rescue and recovery and with rebuilding the bridge "as quickly as possible." He also blamed Congress for failing to pass crucial spending bills, including funding for infrastructure.
Rep. Jim Oberstar (D) of Minnesota, chairman of the House Transportation and Infrastructure Committee, said Thursday he would ask for $250 million in emergency funding for Minnesota. Some will be used for alternative ways to move 140,000 vehicles a day that used to cross the bridge. Congress had authorized $283 billion for upgrading the nation's infrastructure over five years. Mr. Natale says ASCE felt the figure should have been $360 billion.
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Staff Writer Mark Clayton contributed to this report.
Bridge Tragedy Sparks Scrutiny of Federal Inspection Program
By Greg Gordon
McClatchy Newspapers
Friday 03 August 2007
Washington - In a strategic plan laid out in 1998, the Federal Highway Administration set a 10-year goal of shoring up the nation's nearly 600,000 federally funded bridges so that fewer than 20 percent would be classified as deficient.
But Wednesday's stunning rush-hour collapse of a 600-foot bridge span along Interstate Highway 35W in Minneapolis served as a reminder that the vision fell short: More than one in four of those bridges are still rated "structurally deficient" or "functionally obsolete."
The disaster triggered political finger-pointing over the need for greater infrastructure spending and prompted Transportation Secretary Mary Peters to send an advisory urging state officials to immediately inspect roughly 700 similarly designed truss bridges.
"We have a national bridge problem," said Rep. James Oberstar, D-Minn., the chairman of the House Transportation and Infrastructure Committee. He said that 79,523 federally funded bridges are rated "functionally obsolete," meaning they need replacing.
The tragedy also heightened attention on bridge-inspection standards, which already had drawn scrutiny. Last year, a Transportation Department audit of 43 bridges in Massachusetts, New York and Texas found that bridge inspectors routinely miscalculated the load capacity of structurally deficient bridges, posting weight limits that allowed vehicles exceeding the safety threshold or failing to do so at all.
The I-35W bridge over the Mississippi River in Minneapolis has a non-redundant truss design, meaning that the failure of any component of its steel superstructure or the buckling of one of its four concrete piers could cause a collapse.
The 40-year-old bridge was erected shortly before the Silver Bridge over the Ohio River, another non-redundant truss bridge, collapsed due to the failure of a single piece of hardware around Christmas in 1967, killing 46 people. That disaster led to changes in the design of truss bridges, although investigators have yet to determine whether the two collapses had similar causes.
Peters responded to Wednesday's collapse by asking Transportation Department Inspector General Calvin Scovel to review the agency's bridge-inspection program, to ensure that states are "looking at the right things in the bridges," department spokesman Brian Turmail said.
"What troubles the secretary is that the kind of indicators that the bridge-inspection program was designed to flag didn't get flagged," he said. "If you look at the paperwork, there were no indicators that the bridge needed to have traffic reductions in place, as some bridges do. There were no indicators that the bridge needed to be shut."
Democrats in Congress suggested that the disaster signals a widespread problem rooted in national neglect.
"This really should be a wake-up call for America," declared Senate Majority Leader Harry Reid, D-Nev. "We have an infrastructure that is deteriorated and deteriorating - bridges, dams, highways, water systems, sewer systems - and since Sept. 11, we simply have taken our eye off the ball."
Shankar Nair, a nationally known structural engineer who specializes in bridge design, agreed in principle that the nation's bridges badly need to repair problems such as corroding steel or cracked concrete, but said in an interview that few, if any, are in danger of collapse.
"I think our bridges are in terrible shape, and I think we need to spend a bundle of money to bring them up to snuff," said Nair, who's based in Chicago. "But the danger of an actual collapse that causes fatalities is still pretty small. I don't worry (when) driving that the bridge I'm on is going to fall down. And that is especially true of the bigger bridges."
Nair said that even non-redundant truss bridges have performed well and shouldn't provoke major concerns "with modern steels and modern design techniques."
"Highway departments and engineers are conservative people," he said. "We're nervous people. When we say that a bridge is unsafe, it doesn't mean it's going to fall down. It means that the margin (of safety) is not as good as it should be."
Oberstar said he'll press next year to increase the nation's annual funding for bridge construction and repair from $2 billion to $3 billion. He blamed President Bush for slashing Congress' highway spending bill last year by nearly $90 billion.
White House press secretary Tony Snow called the Minnesota bridge collapse a "unique disaster," noting that the state has a rigorous bridge inspection program and that bridge collapses occur on rare occasions. He said that politicians should reserve judgment until experts have determined the cause.
California Democratic Sen. Barbara Boxer, the chair of the Senate Committee on Environment and Public Works, vowed to hold hearings after the August recess "on the condition of our national infrastructure and how we can prevent tragedies like this from happening in the future."
"Many Americans are asking, `Could it happen here?"' said Sen. Patty Murray, D-Wash., the chair of a Senate Appropriations subcommittee and shepherd of a $104 billion transportation and housing spending bill that Bush has threatened to veto.
"He says it spends too much on our nation's transportation infrastructure. I don't see how he can keep making that argument as Americans see the images of a bridge that is now a tangle of steel and concrete languishing in the middle of the Mississippi River."
Are the Dead From the Minneapolis Bridge Collapse Victims of Conservative Ideology?
By Joshua Holland
AlterNet
Friday 03 August 2007
The tragic collapse this week of a stretch of I-35 spanning the Mississippi river in Minnesota was shocking but should come as no surprise. America's core infrastrucure has been falling apart in very visible ways during the past few years. It's a predictable outcome of the rise of "backlash" conservatism; we've swallowed 30 years of small-government rhetoric, and it's led us to a point in which our infrastructure, once the pride of the developed world, is falling apart around us. We're reaping what we've sown.
Minnesota's Republican governor, Tim Pawlenty, reacted to the disaster by calling a press conference and, with a steely determination worthy of Rudy Guiliani, lying to the American people. Pawlenty insisted that inspections in 2005 and 2006 had found no structural problems with the bridge. But the Minneapolis Star-Tribune reported that the bridge "was rated as 'structurally deficient' two years ago and possibly in need of replacement." The bridge was borderline - with a 50 sufficiency rating; if a bridge scores less than 50, it needs to be replaced.
According to the Pioneer Press, the bridge's suspension system was supposed to receive extra attention with inspections every two years, but the last one had been performed in 2003.
The governor had every reason to obfuscate; in 2005, he vetoed a bipartisan transportation package that would have "put more than $8 billion into highways, city and county roads, and transit over the next decade." At the time, he was applauded by many Republicans for his staunch fiscal "conservatism."
It's too soon to say for sure what caused this latest disaster, but as Stephen Flynn wrote in Popular Mechanics, when all is said and done, "investigators will likely find that two factors contributed to its failure: age and heavy use." Those conditions are anything but isolated:
According to a report card released in 2005 by the American Society of Civil Engineers (ASCE), 160,570 bridges, or just over one-quarter of the nation's 590,750 bridge inventory, were rated structurally deficient or functionally obsolete. The nation's bridges are being called upon to serve a population that has grown from 200 million to over 300 million since the time the first vehicles rolled across the I-35W bridge. Predictably that has translated into lots more cars.
It was the second U.S. bridge collapse this week - a span in California fell the day before, with far fewer injuries and no loss of life. The tragedy occurred just weeks after an 80-year-old steam pipe in Manhattan blew up, killing one and injuring dozens more. A year earlier, a section of tunnel in Boston collapsed, killing a woman as she drove home. A year before that, hundreds of thousands of Americans became refugees after New Orleans' pitiable levees collapsed - a graphic illustration of shortsighted public policy if ever there was one. The AFL-CIO estimates that more than one in four roads are in "less than good condition." Minnesota ranks low on their list, with about one in eight failing to make the grade.
It's all part of a larger picture. We have a crumbling power grid and are falling behind the rest of the world in broadband infrastructure. The American Society of Civil Engineers (ASCE) talks of "congested highways, overflowing sewers and corroding bridges" that are "constant reminders of the looming crisis that jeopardizes our nation's prosperity and our quality of life." Every year the engineering society issues a report card grading 15 categories of America's once-premier infrastructure. In 2005, that "core" infrastructure collectively got a "D-," slightly worse than the "D" it received in 2000. Ironically, the nation's bridges received the highest score - a "C" - in 2005.
Experts have been warning of our gradually disintegrating infrastructure for years. ASCE's engineers estimate that it would take an investment of $1.6 trillion over the next 10 years to bring it up to modern standards. That investment would create of tens of thousands of decent jobs and, most economists agree, would likely unleash a new wave of productivity growth. But just as Minnesota's Pawlenty vetoed an increase in that state's highway funds so he could play a fiscal conservative in TV commercials, the GOP-controlled Congress rejected a Democratic proposal in 2002 that would have increased highway funding by $4 billion in a straight party-line vote (because they couldn't stand the fact that the bill also called for a minimum wage increase and an extension of unemployment benefits - ultimately, a pork-laden version with nothing for workers did pass in 2005). Governance, ultimately, is a matter of priorities, and infrastructure takes a back seat.
One of the primary reasons for that is that there aren't organized constituents lobbying for public goods like highways and bridges - people take those things for granted. A thousand grifters have gained office promising to cut taxes as if they existed in a vacuum, without mentioning the cost; no politician has ever won office promising to keep highways from collapsing on their constituents. For 30 years, we've been told by a series of right-wing snake-oil salesmen that they could deliver more and better public services while constantly cutting the taxes that pay for them, but it was always a fraud. The result is that the United States enjoys the third-lowest tax burden among the 30 most advanced economies as its public spaces gradually come apart at the seams.
I would argue that skimping out on infrastructure investments in the name of a low tax burden is a triumph of ideology over commonsense, but it goes beyond that. Conservative philosophy stresses limited government, not bad government, and nothing can change the fact that the public sector remains the only way to organize collectively when there's no profit involved. So nobody seriously believes that the the hidden hand of capitalism is going to step in and inspect and repair bridges that are open to the public. When lawmakers don't fund that work, they know full well that it won't get done.
What's more, the evidence that infrastructure investments result in increased economic productivity is fairly conclusive; some studies have estimated that every dollar invested in public infrastructure yields 104 percent return through increases in productivity.
So something more is going on. Stephen Flynn says, "Americans have been squandering the infrastructure legacy bequeathed to us by earlier generations. Like the spoiled offspring of well-off parents, we behave as though we have no idea what is required to sustain the quality of our daily lives."
Perhaps. And perhaps it has to do with American exceptionalism - in every other country, citizens understand that their society is as good as they make it, while many of ours seem to believe that we're a leading nation according to some divine plan and no amount of bone-headed governance and skewed priorities can ever change that fact.
That's something to ponder as you drive over that bridge or through that tunnel on the way home.
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Joshua Holland is an AlterNet staff writer.
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