The Infrastructure Mess

Infrastructure and public safety once again come to the forefront with the collapse of the I5 Bridge in WA. It's looking like investigators are focusing on a truck that passed through the area shortly before the accident and whether it struck the overhead supports, knocking the span out of alignment. That would take quite a bit of force, unless other issues were at play (including corrosion and a lack of redundancy in structural support).

Time will tell what happened, but thankfully no one was killed in this collapse.

It's a reminder that we are spending far too little on maintaining and upgrading existing infrastructure. The amount we as a nation are spending on infrastructure has fallen to levels not before seen as a percentage of GNP over the past twenty years after peaking during the Stimulus period. We are spending far less in both real dollars and as a percent of GNP than other developed countries, despite critical areas that are not getting support.

Moreover, we're not getting out money's worth (bang for the buck) based on the costs compared to similar projects overseas. Two of the biggest projects are the East Side Access and 2d Avenue Subway lines. Both will improve access to NYC and reduce congestion by carrying hundreds of thousands of commuters each day, but for the cost of the first segment of the 2d Avenue line, several countries in Europe have been able to build out entire subway lines. The NYC subway system is the oldest in the country and essentially operates 24/7/365 with no lines shut down overnight as some of its counterparts elsewhere do. That's beginning the change with the FasTrak service to get repairs done faster and cheaper, but trying to add capacity to an already built-out system in a densely populated area is costly.

Yet, there's room to grow. There's a proposal floating around to get the outer boroughs connected using underutilized rights of way that the MTA doesn't currently use. The Triboro TX would loop through Brooklyn, Queens and Bronx, and link up lines so that commuters don't have to cross into Manhattan to get to their destinations. It makes tremendous sense, and could relieve congestion through Manhattan and wouldn't cost nearly as much as a new subway through Manhattan, except that the MTA doesn't have room in its capital budget to do it - and the lack of political will to get it done either. NIMBYs have been trying to get some of that turned into park, rather than revert to subways that would increase property values of neighborhoods along the routes and prospective station locations. Turnover at the top of the MTA isn't helping either.

But it still comes back to costs for infrastructure. We want it. We need it. It's indispensable, and yet we refuse to pay for it and politicians aren't going to do anything when they can't do ribbon cuttings (so basic maintenance gets shafted).

But big projects like bridges, tunnels, subways, and mass transit are just the tip of the iceberg on infrastructure and public safety.

In light of the tornado that destroyed the town of Moore outside Oklahoma City, there are some calls to require construction of storm shelters and storm cellars in new buildings and retrofit existing structures.

The Oklahoma Governor Mary Fallin is refusing to support a mandate that would require storm celler/shelter construction in new or existing structures. It's absolutely mind-boggling.

Despite the life-saving potential of personal storm shelters, the cost remains a deterrent. So, too, does a general resistance to government mandates in politically conservative states such as Oklahoma, where tornadoes are most prevalent. Even the director of an association of storm shelter manufacturers, based in Texas, is opposed to a storm shelter mandate for new homes.

"Any time a governmental entity says 'thou shalt' and tries to take an individual decision into the public domain, it's going to get pushback, and you're also going to raise the cost of things," said Ernst Kiesling, executive director of the National Storm Shelter Association and a retired civil engineering professor Texas Tech University.

The science of storm shelters has advanced considerably since Dorothy failed to make it to the tornado cellar at Aunty Em's Kansas farm in the 1938 movie the Wizard of Oz. Some shelters still are dug underground in the backyard. But they are increasingly made with specially fabricated concrete and steel doors to meet Federal Emergency Management Agency specifications. And they aren't necessarily underground. In some cases, closets or bathrooms are being fortified to double as "safe rooms" that can withstand furious winds even if the rest of the house is blown away.

In 2011, Oklahoma announced the SoonerSafe incentive program, offering federally financed rebates of up to $2,000 to residents who install storm shelters. The state uses a lottery-style drawing to select rebate winners from among the thousands of online applications. Sherry Wells said she won this year. She and her husband decided to get the biggest shelter available- a vault-like box with wooden benches - at a cost of $4,800. The project was so freshly finished that the Wells hadn't even submitted their rebate forms when the tornado hit on Monday.

"If it wasn't for the hand of God and the cellar, we wouldn't be here," Wells said as she sorted through the rubble of her home Thursday.

A little over 3,000 residential storm shelters are registered in Moore, a city of about 56,000, said community development director Elizabeth Jones.

Moore Mayor Glenn Lewis wants to propose a city ordinance requiring all new homes to have storm shelters. But realistically, he said, city officials may be able to require them only in new assisted living facilities and apartment complexes because of cost concerns. Contractors will be part of the conversation with the City Council to see whether a broader requirement is possible, Lewis said.

"We want to be competitive," he said. "We don't want to price them out of the market."

Asked at a news conference if a similar mandate might be considered statewide, Oklahoma Gov. Mary Fallin quickly shot down the suggestion.

Their primary concern is cost.

It would cost anywhere from $3,000 to $5,000 to integrate a storm room into a new build. That is the difference between life and death. In fact, one family who won a lottery to get a rebate for a storm shelter survived the Moore tornado just weeks after finishing the work but before they were able to submit the rebate paperwork. That family is alive because of the storm shelter.

The cost definitely works in favor of installing and mandating the shelters, as compared to the funeral costs for those folks who were killed.

This isn't about a lack of money. It's about lacking the will to make it happen and adjusting priorities to focus on public safety and well being. The state of Oklahoma, along with the other Tornado Alley states have no statewide requirements for requiring storm shelters in new buildings, let alone retrofitting them into existing structures. The costs can be depreciated and spread out over the life of the structure, and moreover, the costs can be absorbed simply by reducing the square footage of a private residence with the structure built in by 30-50 square feet.

I-35 Bridge Reopens

The new I-35 bridge over the Mississippi River has opened just over one year after the truss span collapsed, killing more than a dozen people and injuring 145.

Here's a time lapse video and live camera of the bridge. The new bridge, designed and built by Figg Bridges and Flatiron Construction, was reopened three months ahead of schedule and incorporates additional lanes, is light-rail capable, and is designed to last 100 years. The company will get a bonus of up to $27 million for completing it ahead of schedule.

New Photos Reveal Problems With Minnesota Bridge That Collapsed

Photos have been released showing problems with the Minneapolis bridge that collapsed August 1, 2007, killing 13 and wounded over 100 others. The photos, taken in 2003 [ed: corrected for date instead of range] by a consulting firm hired by the state DOT investigation, show gusset plates visibly bowing. The plates are key structural members that join together steel supports that make up the trusses that carry the bridge loads.

No action was taken at the time the photos were made. And you can be assured that the families of those who died in the collapse are wondering how and why no action was taken when the photos clearly show that something wasn't quite right with the bridge support systems.

Two photos, part of a report issued earlier this month by the National Transportation Safety Board, reveal slight bends in gusset plates that hold beams together at two separate connecting points. The plates are in areas believed to be among the first points of failure when the span collapsed.

The NTSB's Office of Highway Safety confirmed that the bowing is part of the investigation into why the bridge collapsed Aug. 1, the Star Tribune newspaper reported Sunday.

NTSB Chairman Mark Rosenker didn't comment on the photos, but has said the original design for the bridge specified steel for those and other gusset plates that was too thin.

NTSB spokesman Terry Williams told the Star Tribune the bowing is among "the many things that we are looking at as part of this investigation."

The newspaper said inspection records make no mention of repairs to the bending gusset plates.

Williams did not immediately respond to an Associated phone message seeking comment Sunday. State transportation department spokeswoman Lucy Kender also did not immediately respond to phone and e-mail messages.

The two photos are believed to have been taken by URS Inc., a San Francisco consulting firm the state hired to examine the bridge from 2003 to 2007.

"URS and the state have both got a lot of explaining to do as far as why (the bending) was not observed, and if it was observed, why that was not immediately investigated," James Schwebel, an attorney representing a group of victims, told the AP on Sunday. "How could it possibly have been missed?"

The structural load that the bridge was carrying was increased twice since it was built in 1967, most recently when concrete barriers were installed in 1998. Also, an additional 190 tons of construction materials was on the bridge at the time of the collapse.

Construction on the replacement span continues. The concrete piers that will carry the load across the Mississippi River are under construction, and the approaches to the bridge are also well underway, with a scheduled completion date of Christmas 2008. A schematic of the new bridge and how it is being built can be found here.

Design Flaw Brought Down Minnesota Bridge?

Have investigators found a design flaw with the bridge? It is possible, but with the investigation in its earliest stages, I wouldn't draw too many conclusions, although federal and state officials aren't waiting for the investigation to be complete before calling for additional scrutiny on a part of a bridge called a gusset plate. It's a piece of structural steel that links two or more pieces of a bridge together and is quite common in bridge construction. They're specifically worried that weight added during rehabilitation or other construction work may have stressed a gusset plate to the breaking point.

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 today.

The Federal Highway Administration swiftly responded by urging all states to take extra care with how much weight they place on bridges when sending construction crews to work on bridges. Crews were doing work on the deck of the Interstate 35W bridge 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 it had in the collapse.

Still, in making public their suspicion about a flaw, the investigators were signaling they consider it a potentially crucial discovery and also a safety concern for other bridges around the country. 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 today.

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-type bridge.

In Minneapolis, state transportation department officials seemed stunned 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.

Investigators are looking into whether the designers of the bridge miscalculated the strength of the parts, which would mean that the seeds of the bridge collapse was sown in 1964, and may have had little to do with maintenance budgets. However, would a proper inspection have uncovered such a deficiency that would have required immediate changes to the bridge?

Slow Progress In Minnesota Bridge Collapse Investigation

Investigators are looking into whether tons of construction materials and equipment may have played a role in the collapse.

Trucks carrying tens of thousands of pounds of crushed stone were parked on the Interstate 35W bridge, and more stone was sitting on the deck when the bridge collapsed, investigators said Sunday, raising suspicions that the added weight of materials intended for repairs may have played a role in the bridge failure.

The chairman of the National Transportation Safety Board, Mark V. Rosenker, said investigators had questioned employees of Progressive Contractors Inc., which was doing work on the bridge deck, regarding quantities of various materials, specific equipment they had put on the bridge, and where the materials and equipment were on the bridge. The weight and location will be entered into a computer program, Mr. Rosenker said, to calculate the stresses generated on each girder and other bridge components.

So far, investigators say they have ruled out nothing and will consider everything from the expansion and contraction of the bridge in the extreme weather conditions of Minneapolis to the possible corrosive role of bird droppings.

The stone was being used to add a two-inch layer to the bridge deck. Its weight, and the weight of the trucks carrying it, would most likely not be a threat to a bridge in good condition, engineers said, but could play a role in causing the failure of a structure that was already weakened.

Completion of the computer analysis is probably still weeks away, investigators said. Once the wreckage is removed from the Mississippi River, the plan is to lay out the debris on shore and identify each piece of metal and its role in the structure, in an effort to determine what failed first.

Meanwhile, new federal rules on bridge design and engineering are scheduled to take effect in October. The rules have been decades in the making and address issues like redundancy, longevity and current weight loads experienced by bridges across the country. The new rules will not be retroactive in nature, which means it will apply to new construction only.

States have been slowly applying the new rules for years, some better than others. Minnesota is at the forefront, with 100 percent enforcement on new bridges as of last year. New York has been slower, and California slower still.

States that fail to follow the new rules after October could jeopardize their federal financing.

The rules, highly complex, call for major improvements in the design of bridge steel, concrete and foundations. They are more conservative, for instance, in their assessment of the sturdiness of driven pilings, and in some cases will raise the cost of bridge foundations.

Officials called the rules the biggest change in federal regulations for bridge design since 1931. Behind the change, they said, are such factors as more realistic assessments of highway traffic as well as advances in the statistical analysis of past bridge failures and their causes.

Among other things, the rules will produce bridges better able to withstand peak traffic stresses and severe weather, as well as “extreme events” like ship collisions and earthquakes.

“It’s going to increase reliability, which translates into bridges that are safer, more cost efficient, and have longer design lives,” said Kelley C. Rehm, program manager for bridges and structures at the American Association of State Highway and Transportation Officials, which wrote the new rules.

“It doesn’t mean existing bridges are going to fall down,” Ms. Rehm added. “In the past, some were overdesigned, and some didn’t have as much of a safety factor as we’d like to see. Today, we know a lot more about how loads are doing to affect the bridges, and why they fail.”

Surprisingly, experts say most bridge failures involve not structural failure of the span itself but of its foundations. For instance, churning water can undermine driven pilings, causing the whole bridge to collapse suddenly.

Deciphering Causes

While the search for victims continues at a very slow pace due to near zero visibility conditions in the Mississippi River, investigators are still examining the scene of the collapse of the I35W bridge in Minneapolis and are wondering why a section of the bridge appears to have shifted 50 feet off axis as it collapsed. That may lead to how and why the bridge collapsed, though it will take time:

What's getting investigators' attention is the way the southern part of the bridge fell in a video they've already examined -- recorded by a security camera near the bridge's north end -- and the way the section settled after the collapse.

"It appears that it has shifted approximately 50 feet to the east and when we compare that to what we've seen in the rest of the bridge -- the rest of the bridge appears to have collapsed in place, " said NTSB Chairman Mark Rosenker, who is leading a 19-member team charged with determining the cause of the accident.

"We're going to take a look at any unique design factors that could have created that shift...for whatever reason."

It's not the answer to the mystery of why the bridge fell, but a step forward, Rosenker said.

The NTSB will also examine three more videos provided by the Army Corps of Engineers, one of which may show another view of the bridge falling, Rosenker said. Investigators aren't optimistic the other two will show anything because they weren't pointed at the bridge.

On Thursday, U.S. Transportation Secretary Mary Peters notified state transportation departments to immediately inspect all bridges of the same design as the one that collapsed Wednesday on Interstate 35W into the Mississippi River in Minneapolis.

There are over 700 bridges of similar design, including several along the New York State Thruway and I90.

Investigators continue to pore over the paper trail on the bridge, and other states are taking up inspections of their bridges and infrastructure to see if there are similarly deficient structures that need immediate attention.

Money does not appear to be an issue here. According to the Minnesota Department of Transportation, federal transportation funding increased 46% for 2005-2009 over the prior funding period, which was set at the end of the Clinton Administration.

U.S. President George Bush signed a $286.4 billion six-year transportation reauthorization bill Aug. 10, 2005 that covers federal fiscal years 2004-09.

Although the details of the reauthorization package are still being reviewed, Minnesota state and local governments can expect to receive about $3.5 billion in federal transportation funding through 2009, an increase of about 46 percent (or about $1.1 billion) over the previous six-year bill.

So, if the bridge needed to be replaced or significantly repaired, the money was available.

However, as the investigators are looking closer at the structure itself, it appears that the collapse may have been due to design defects - the lack of redundancy built into the bridge itself. Those are decisions made decades earlier - both as a result of costs to build, and assumptions over bridge use, maintenance and replacement at the end of its useful life.

UPDATE:
Congress has voted on measures to provide funding to rebuild the bridge. The measures voted yesterday would amount to $250 million. Technical amendments are likely, and may increase the overall funding to $255 million.

Could the Minneapolis Bridge Collapse Have Been Averted?

The death toll now stands at five, with eight people missing. CNN reports the following:

The bridge collapse during Minneapolis' rush hour Wednesday has raised questions about structural problems with bridges in general and the I-35W bridge in particular.

Dan Dorgan, Minnesota's top bridge engineer and the man responsible for bridge inspections, said an engineering firm last year examined the bridge and gave the state two options: add steel reinforcements to the bridge or further inspect welds on the structure, CNN affiliate Internet Broadcasting reported.

Both scenarios envisioned the bridge would be replaced or substantially rebuilt around 2020, according to Internet Broadcasting.

"We chose the inspection route," Dorgan said, because the firm believed drilling holes to add the steel would have weakened the structure.

"We thought we had done everything we could," Dorgan told Internet Broadcasting. "Obviously, something went terribly wrong."

The investigations will focus on what happened but it will take time to ascertain the cause, and it will also take time for that knowledge to be translated into repairs or replacement of similar structures around the US.

UPDATE:
Ed Morrissey, who lives in Minnesota, notes the following:

It doesn't appear that money or neglect played a part in this collapse. It looks instead that MnDOT either didn't evaluate the bridge properly, or that the fatigue it noted didn't have anything to do with the collapse.

Other reports from around the country have called into question the kind of inspections that are done and whether they could accurately spot flaws. That's quite troublesome, especially since many inspections do not utilize remote sensing technologies but rather rely on a visual inspection, which may not uncover serious flaws lurking beneath the surface.

Yet Another Obligatory Post On Infrastructure

News reports are flooding the airwaves over the poor condition of roads around the country, and of specific interest to me is those in the New York City metro region. None of this should be surprising. I've been writing about the crumbling infrastructure in the region, including subways and tunnels, mass transit and transportation in general, the power grid (including blackouts and energy policy), ever since I started this blog.

The number of bridges considered obsolete in New York or New Jersey is about 25% of all bridges - double the number found in Minnesota. And Rhode Island, Massachusetts, and the District of Columbia are even worse. There are simply many more bridges in New York and New Jersey and many of them are older. However, that's no excuse for either state to shirk its responsibility to maintain all its infrastructure.

It isn't glamorous or sexy, but it is crucial, vital, and absolutely necessary.

Would it surprise you that the approach spans to the Brooklyn Bridge are considered in poor condition? They're more likely functionally obsolete - carrying more traffic than they were designed for and whose condition has degraded over time. They need to be replaced. Several years back, New York City built a special arch bridge under part of the Manhattan approach to support a deck truss span and keep the entire bridge open and safe. NY1 reports on the condition of the Brooklyn Bridge, but gets the math wrong:

Transportation officials say all of the 787 bridges maintained by the city met federal and state safety standards in their most recent inspections last year, however three are considered to be in poor condition, including the 150-year-old Brooklyn Bridge.

DOT officials insist the span itself is safe, and say the problems deal with joints on the ramps leading to the bridge itself.

"The rating could involve different parts of the bridge and it depends what parts we're talking about and how it pertains to the structural integrity to the whole system,” said Michel Ghosn, a professor of civil engineering at the City College of New York. “So if it's just one part, that does not mean the whole bridge is about to collapse."

The city has scheduled renovations on the Brooklyn Bridge for 2010.

The Brooklyn Bridge was completed May 1883. It is 2007. That makes the bridge 124 years old - not 150 years old. The sections with the serious concerns are the approach spans, which are much younger than the rest of the bridge.

So, what are the worst bridges in the nation? These:

Half of the 20 bridges are located in New Jersey and California, including the famous San Francisco-Oakland Bay Bridge (pictured above).

The New Jersey Route-21 Bridge over the I-80 corridor is the busiest, with more than 518,000 daily commuters and a 49 percent sufficiency rating. The lowest rated bridge is the Raritan River Smith Street Bridge in New Jersey which 208,000 commuters drive across daily. It earned a rating of only 20 percent.

The Federal Highway Administration's sufficiency rating serves only as a guideline and does not mean that a bridge is necessarily unsafe.

20 Most Deficient, Heavily-Trafficked Bridges:

20.2%. New Jersey: Raritan River Smith St. Bridge over the Garden State Parkway. Daily commuter load of 208,000.

23.6%. New Jersey: Elizabeth River Bridge over the Garden State Parkway. Daily commuter load of 198,200.

27.2%. New Jersey: Port Reading Bridge over Grove Avenue. Daily commuter load of 191,530.

32%. New York: Lee Avenue Bridge (Section A) over Route I-278. Daily commuter load of 202,650.

32.1%. California: San Francisco-Oakland Bay Bridge (Ala-Oak) over I-80. Daily commuter load of 277,700.

32.1%. Hawaii: Kapalama Canal over Halona Street. Daily commuter load of 211,528.

34%. New York: Joralemon Street Bridge over Route I-278. Daily commuter load of 202,650.

35%. Illinois: Stewart Avenue Bridge over I-90. Daily commuter load of 238,500.

36%. Colorado: South Platte River Bridge over I-25ML. Daily commuter load of 208,353.

42.5%. Virginia: Boundary Channel Bridge over Shirley Memorial Highway. Daily commuter load of 210,993.

46.3%. Georgia: Banberry Road Bridge over I-75. Daily commuter load of 266,060.

46.3%. California: San Francisco-Oakland Bay Bridge (SF section) over I-80. Daily commuter load of 204,900.

46.3%. New Jersey: Elizabeth River Bridge over Garden State Parkway. Daily commuter load of 198,200.

47%. California: 5th Avenue Bridge over I-880. Daily commuter load of 240,000.

48%. California: Noakes Street Bridge over I-710. Daily commuter load of 240,000.

49%.New Jersey: Route-21 Bridge over I-280. Daily commuter load of 518,100.

49%. California: Bayshore Viaduct over Rte 101. Daily commuter load of 256,700.

49%. New York: Lee Avenue Bridge (Section C) over I-278. Daily commuter load of 202,650.

49%. Massachusetts: Cape Cod Canal over Route 28. Daily commuter load of 195,000.

50%. California: Metrolink over I-710. Daily commuter load of 235,440.

As I have said before, maintenance and daily repair and oversight isn't glamorous but it's crucial to maintaining the safety and integrity of the transportation infrastructure.

UPDATE:
It didn't take long for some to start linking Mayor Bloomberg's congestion pricing tax to the Minneapolis bridge collapse- the need to provide dedicated funding for infrastructure maintenance, repair, and replacement as needed. Indeed, as Ms. Cohen points out, Bloomberg's own plan makes a point of mentioning the importance of providing upgrades to the infrastructure.

Mayor Bloomberg addresses these problems in his PlaNYC. That strategic plan for a "sustainable" city of 2030 includes specific priorities for upgrading the transport, energy and water networks that make the city work.

Indeed, the largest expenditure of revenues - more than $15 billion - from the mayor's proposed congestion-pricing program would be to bring transportation infrastructure to a "state of good repair." This includes roads and bridges maintained by the city Department of Transportation, as well as the subway's stations and vital hidden systems - power, signals, ventilation, pumping, etc.

More and more, to achieve a state of good repair requires going beyond in-kind repairs and replacements - to reinforcing the bones and upgrading the brains.

Rebuilding a bridge deck today means accounting for modern traffic levels and the extra weight of trucks, vans and SUVs. Replacing an obsolete subway signaling system means upgrading from century-old technology to solid-state switches and communications-based train control. Such a "CBTC" is under way now on the "L" line.

Installing that new system has been difficult - with the delays and cost overruns that mark most new-technology projects - but when completed, it will allow trains to run more frequently on that now-crowded line. The No. 7 line will get the upgrade next.

Investments like these are necessary to enable the city to grow in a healthy and responsible - yes, "sustainable" - way.

And all of that is just concerned with keeping what already exists operational. As the city grows by a million residents between now and 2030, infrastructure networks will have to be expanded and whole new neighborhoods built - complete with roads, transit, sewage systems, water mains, electrical substations and the rest. And then all of that infrastructure will have to be maintained as well.

It also didn't take long for the political blame game to get going. The Democrats/progressives are pushing the meme that Republican doctrine is responsible for the bridge collapse. Really? They know what caused the collapse before the NTSB or other investigators? By all means, share it. Oh wait - it's because taxes were not high enough. Gotcha. Never mind that it is the legislature - whether in state or fed that is responsible for appropriations, not the executive (politics 101 is foreign to these folks). If they didn't think that the budget for transportation was sufficient, the legislatures - and in Minnesota it is dominated by Democrats - could have added to the budget. They didn't.

Further, what if it is shown that the failure was due to the fact that when the bridge was designed and completed in 1967, that the design itself was the reason for the collapse? Democrats were in charge at that time. We already know that this particular design doesn't have redundancies built into the structure so that if a specific section fails, other sections could carry the load. When those critical sections fail, the whole structure can fail.

What I'm getting at is that this blame game wont get very far, and it surely wont be productive either. It might score political points for a few people, but the safety of millions of Americans wont be enhanced one iota. Ensuring that people truly prioritize maintenance on these bridges and structures over spending on other programs that are of dubious intent at best is the only way to improve the safety and reliability of the infrastructure.

Minneapolis Bridge Collapse Update

Law enforcement has revised the number of those killed downward to four, and video of the collapse has surfaced. It doesn't show the entire span unfortunately, and it would appear that the start of the collapse occurred off camera.



Hot Air has more information, including excerpts from engineering reports on the bridge.

Look for more hometown coverage from Lileks, Captain Ed, and Powerline.

A 2005 structural report on the bridge, which graded it structurally deficient is here.

UPDATE:
As I'm from the NYC metro area, I am well aware of the thousands of bridges, overpasses, and viaducts and have travelled over many of them over my life. Some are in extremely poor shape, but the City has been repairing or replacing some of the older bridges - 3d Avenue, Macombs Dam, and rebuilding others, including the Triborough, Whitestone, Throgs Neck, 59th (Queensboro), WillieB, Manhattan and Brooklyn. The Port Authority is also doing work on (or has completed work) on the Outerbridge, Goethals, and GWB. They've also done upgrades on the Holland and Lincoln Tunnels.

Rehab and constant maintenance is the only way to stay ahead of problems.

I expect Mayor Bloomberg to push the congestion pricing scheme again in the coming days, focusing on what the tax can do for infrastructure repair and maintenance - to avoid the MN situation. In this environment, I think he'd have a much better chance of getting people to agree to that tax.

UPDATE:
Investigators are focusing in on vibration and fatigue cracking as possible causes for the collapse.

Investigators looking into the cause of the Interstate Hwy. 35W bridge collapse are likely to focus on two primary causes -- vibration and fatigue cracking, the former chairman of the National Transportation Safety Board said in an interview early Thursday morning.
Jim Burnett said they should look at whether vibration from the construction work contributed to the collapse, or whether a train that was under the bridge at the time may have been moving, contributing vibration to the bridge.

"Vibration is one of things that cause cracking to propagate," he said. "They will be looking at that."

Burnett, who is in town for a Republican National Committee meeting, was watching the scene at 5 a.m. with other onlookers at the University Avenue SE. northbound entrance.

He also said he was intrigued by a 2001 University of Minnesota study that found signs of "fatigue cracking" in the bridge supports, though he noted that a later report apparently concluded that the bridge was in no immediate danger and did not need major repairs.

"I think that decision is going to come under new scrutiny," he said.

A 2005 federal study found that the bridge was "structurally deficient."

"A structurally deficient bridge might be one not adequate for the traffic it takes, but not necessarily dangerous," Burnett said. "But a lot of structurally deficient bridges are dangerous."

UPDATE:
The bridge design in Minnesota reminds me of a similar bridge designed over the Hudson River in Albany. The Patroon Bridge, which carries I-90, has had numerous problems with cracks over the years, and is monitored annually.

The Times Union took a close look at this bridge for a story published Jan. 14.

We reviewed inspection records obtained from the state Department of Transportation as the result of requests under the state's Freedom of Information Law and questioned state transportation engineers familiar with the Patroon Island Bridge and its issues.

The greatest concerns engineers have about this bridge aren't related to the unsightly crumbling concrete you can see from your car. DOT has undertaken an aggressive monitoring program to watch cracks in the structural steel below the road surface.

When necessary, contractors work to stem the damage in crack-prone areas by drilling holes that can stop horizontal cracks from growing and installing steel reinforcing angles to stabilize twisting floor beams.

The most recent inspection was completed in November 2006.

For now, DOT engineers say the extra care and attention are keeping the bridge in safe shape. Overall, it has a rating of 5 on a 7-point scale. That's the rating normally given to a bridge that functions fine with minor deterioration.

Still, all that attention costs money and valuable engineers' time, and the 1,783-foot-long Patroon, which spans the Hudson River between Albany and Rensselaer counties, is busier than ever.

The bridge has seen numerous other problems relating to cracks in the structural members and joints, in addition to the concrete spalling on the surface of the deck and railings. Replacing the bridge would top $100 million, so a regular maintenance program is in place to deal with the ongoing issues with cracks. Some of the problems have been addressed in prior repairs, but staying on top of the condition of the bridge is paramount to maintaining the safety of the public.

UPDATE:
NJ Governor Corzine has ordered the State DOT to inspect all bridges across the state and provide a report within 45 days. He said that any bridges deemed unsafe would be closed to traffic.

Corzine said New Jersey has 6,400 bridges, 2,400 of which are under state control. The other bridges are either under federal or local government control, but he said the state will look at all of them.

"I want to make sure that the conditions of our bridges has been monitored," Corzine said during a visit to the South Plainfield Senior Center.

He said he wants an interim report from the state transportation commissioner in a week and a final report in 45 days. Specifically, Corzine said he wants the report to detail bridge conditions, safety ratings, how often the bridges are inspected and the cost of needed repairs.

"If there are any unsafe bridges, they will be shut down," Corzine said. "Safety comes first."

I expect Corzine or the legislature to consider proposing an increase in the gas tax to fund the transportation trust fund to deal with the crumbling state transportation infrastructure, especially considering that New Jersey has one of the lowest motor fuels taxes in the country but has one of the densest concentrations of roadways and bridges in the country.

UPDATE:
Investigators are going to be reconstructing the bridge, much as they would do in an aircraft crash reconstruction.

Mark Rosenker, chairman of the National Transportation Safety Board, said today the investigation may take a year or more. The reassembly can help the probe, not unlike the way aviation disasters are treated.

"This will be a complex investigation ... the first thing we must do is recover the pieces."

Rosenker said that the head of the NTSB's materials lab in Washington, D.C., would arrive in Minneapolis Thursday afternoon to take part in the investigation.

He and Minneapolis Police Chief Tim Dolan put out a plea for members of the public who may have photographed the bridge collapse to provide their still photos and videotape to authorities.

Breaking: Bridge Collapse in Minneapolis

My thoughts and prayers go out to the families and friends of those affected by the I35W bridge collapse across the Mississippi River. The collapse occurred shortly after 6:00PM local time. Hot Air has regular updates and posted the image at left. More than 50 people were injured and it appears that three people were killed. Rescuers are still at the scene looking for victims. It also appears that at least 50 vehicles were on the bridge at the time of the collapse.

Doug Ross has photos of what the bridge looked like before the collapse, in addition to the one here at right. It was a truss design built in 1967.

James Lileks, a Minnesota local, is on top of the story, as is Powerline.

There are a couple of possible causes a structural failure that could be at fault here. One is along the lines of the Mianus River Bridge collapse in Connecticut in 1983. Metal fatigue, precipitated by rust, may be the root cause. The other may be scour of the footings, undermining their stability (that caused a collapse in upstate NY several years back - NYS Thruway in Schoharie County) .

After the Mianus bridge collapse, state and feds got real busy in inspecting bridges and other structures for collapse potential and pin and hanger designs were reinforced (that was the design that failed in CT). After the Schoharie Creek failure, bridges were also inspected for scour and riprap added to protect footings and foundations from the scour of water.

The problem is that many states have not done a sufficient job staying on top of their infrastructure - and this may be yet another tragic reminder of what happens when you don't. Indeed, as I noted earlier today, New Jersey has been lax in inspecting dam and flood control structures around the state despite the law mandating regular inspections.

Inspectors will look at everything from soil conditions to see if scour was a problem that undermined the footings to metal fatigue, to conducting tests on the metal and concrete in the structure. When the cause is finally determined, expect to see inspections turn up problems in similar structures around the country and the safety of those bridges reassessed in light of the findings from this disaster.

UPDATE:
Captain Ed is providing running updates as he lives in Minnesota.

UPDATE:
Sadly, the death toll has gone up to six, and more than 37 injured.