Skip to comments.Collapse an opportunity to reassess bridge safety
Posted on 04/30/2007 10:09:45 AM PDT by SmithL
Burning down a freeway is not easy.
But set off enough high-octane fuel at the wrong place and even multiton supporting steel girders turn wobbly as a chocolate bar in the sun. That is what a speeding gasoline trucker managed to do before dawn Sunday to the busiest interchange in Northern California.
Authorities still are piecing together how one of the 18-wheelers traversing the Bay daily crashed and erupted into a fireball that collapsed one freeway onto another at untold disruption to regional traffic.
Miraculously, no one plunged into the inferno, the void it left behind or the debris below. But some experts think the incident calls for a review of heat and blast vulnerability for critical interstate spans.
"This time we were lucky," said UC Berkeley civil engineering professor and steel bridge expert Abolhassan Astaneh-Asl. "This is a wake-up call for major bridges."
State officials pinned blame on driver James Mosqueda, 51, and his employer, and they suggested the state was moving rapidly to rebuild the damaged portions of Interstates 580 and 880 more or less as they were built 50 years ago.
The episode was a freakish "anomaly," according to Will Kempton, head of Caltrans.
But fiery tanker crashes have collapsed freeways in Philadelphia and Boston, and now homeland-security analysts fear copy-cat terrorist attacks.
The burning tanker at the MacArthur Maze released over three hours about the same energy as the split-second detonation of 200 tons of TNT, equal to an extremely low-yield atomic bomb.
"It certainly is a message of something we should be concerned about, and it doesn't take a rocket scientist to figure it out," said David McCallen, a senior executive at Lawrence Livermore Lab's nonproliferation and homeland-security directorate.
The light, flexible steel spans of the MacArthur Maze survived the 1989 Loma Prieta quake that pancaked the Cypress Freeway, which was made of stiff concrete.
But at 3:41 a.m. Sunday, Mosqueda flipped and ruptured his tanker at almost precisely the Achilles' heel of the arching skyways -- the underside of the pier where thin, supporting steel girders are unprotected by concrete or anything else, according to UC Berkeley's Astaneh-Asl.
"I think this was really the perfect fire, tragically," said Astaneh-Asl, who studied the MacArthur Maze intensely after the earthquake.
The extent of Mosqueda's fuel load was unclear Sunday. But at least 8,600 gallons of unleaded gasoline ignited in a continuous roar -- more fuel than burned inside the World Trade Center towers on Sept. 11, 2001 -- and turned the 20-foot space between I-880, where Mosqueda crashed into a guard rail, and the I-580 overhead into an oven that roasted the exposed steel girders to more than 2,000 degrees.
At 1,000 degrees Fahrenheit, steel in girders and bolts goes soft, said Astaneh-Asl, who studied the collapse of World Trade Center towers for the National Science Foundation.
"When steel gets that warm, it loses its strength and cannot carry its load any more," he said. "It's not to say the steel melted. Some portions may have melted, but the steel got soft, like rubber."
Other experts say structural failure can come at even lower temperatures.
"The bottom line is this kind of thing can happen," said Forman Williams, a pre-eminent combustion expert at UC San Diego, who was tapped by the federal government to explain the World Trade Center collapse. "It is a rare event, but all of these are rare events, and the more of these you can protect against, the better off you are. ... You don't know until you do the study."
Caltrans officials dismissed the notion Sunday of fireproofing freeway stilts and bridges. Astaneh-Asl said roadways really cannot be fireproofed like buildings, partly because of vibration.
But he suggested that some of California's most critical bridges and interchanges might deserve the extra expense of coating exposed steel girders in a few inches of concrete.
That coating might cost 5 percent to 10 percent of the construction cost for the bridge but be enough to delay collapse for two hours, perhaps enough time to cool or extinguish a fuel fire.
"From an accidental standpoint, these are definitely rare events," said Livermore's McCallen. "But I think this will probably elicit some additional debate within the (engineering) community about whether something more for fire is needed.
"It's certainly something that people who worry about homeland security should keep at the forefront of what they're thinking about."
What does the octane level have to do with it?
Gasoline has a lot of energy. That's why we power automobiles with it.
Rosie O’Donnell should be hired to supervise rebuilding the bridge. She is knowledgeable about physics and engineering. She will be able to assess how to build the bridge to resist such accidents in the future.
While we’re on the subject, what’s with these tanker trucks full of flammable products going down the freeway? What has the Bush administration done to promote truck safety? Has Hillary weighed in yet on this?
Anybody have bull dyke lez Rosie's email address? I'd like to send this to her.
Yeah. I really wish these reporters could resist the urge to get technical when they are totally clueless. Just tell us who, what, where, why and when, to the best of your limited ability.
Unfortunately, there will be more of these articles written and they will only get worse as they try to out-do each other.
No doubt some idiot will propose banning the transfer of fuel on the highways.
The episode was a freakish "anomaly," according to Will Kempton, head of Caltrans.
No, it wasn't. It was a simple case of a trucker hauling a dangerous load who was going too fast and lost control of his rig.
She can also test it's support by walking on it.
We *clearly* need a Congressional investigation into bridge safety! Subpoena everyone in the Bush Administration you can!
(I give it two days before some nitwit demonrat is actually calling for a Congressional investigation and subpoenaing the Transportation Secretary.)
They are working to allow Mexican trucks and drivers to go anywhere in the US.
yes it was planned by Karl Rove. This was done to show that even a relatively small explosion can cause the steel to lose strength and collapse. It was all done to embarrass Rosie O’Donnell.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
If you think about it at all, it’s much easier to “melt” steel in a closed building with a much lower safety marging than a highway overpass.
And the steel in the WTC didn’t melt, it went into “yeild”, leading to catastrophic failure.
"OK, ok, the
second, third, fourth, fifth, sixth, seventh, eight, ....
The great structural materials engineering expert, Rosie O’Donuts, couldn’t be contacted...
I have irrefutable scientific proof < SPITTLE> that THAT BRIDGE WAS DESTROYED BY EXPLOSIVE CHARGES PLANTED BY THE CHENEY ADMINISTRATION AS A PRETEXT TO PUSH US IN WAR!!!!!!!!! < /SPITTLE>
Really, the amazing thing is that horrendous accidents involving gasoline tankers don’t happen more often. When you consider how many of them are on the road at any given time, and just how dangerous a tanker truck full of gasoline is, they’re really involved in very few incidents. The companies that own and operate gasoline tankers tend to be very safety-minded. When an accident does happen, however, they do tend to be pretty spectacular!
Nah... just find out the material used in her upsidedown hanging straps, and we can have a suspension bridge up really quick!
But WHY should it have hit a PIER???
Why are there not vertical walls along these roads at critical points??
No harsh impact, just a sliding along.
After all, they've installed stuff like this on racetracks!
East bound I-70 in Utah, where it comes down off of the San Rafael Swell, the inner lane wall appears to be over 8 foot tall!
Thanks for that reminder of the low caliber of our public education system.
[That, too, is Bush’s fault, of course; his collaboration with Ted Kennedy on NCLB notwithstanding.]
Sabak Transportation had another rollover last June in Vallejo, CA. 4500 gallons into a creek.
I've gone through some of those turns quite a number of times in my life on the trips to and from my brother's place in Berkeley, and they're pretty hair-raising and adrenalin-pumping if you're not completely focused on driving at or below the recommended speeds.
It's not that hard to piece together. If the driver was unfamiliar with the lay of those roads, I can't bring myself to condemn him a whole heck of a lot. I've left a skid-mark or two on those ramps myself, though I wasn't hauling more than 17 gallons of gasoline at the time. The ramps are quite fun on a motorcycle, though.
fortunately this accident by a bozo speeding driver is not expected to do much damage to California GDP.
But does anyone else find it strange the bad guys haven’t tried this yet as these days it is much easier to hijack a gas truck than a plane. if osama didn’t have such a fixation with planes...
the damage to the economy that could be done by a few well placed trucks in major metro areas is incalculable. and one would think it wouldn’t be too difficult for middle easterners to find employment in the oil industry here.
at the very least there should be some sort of driver screening for hazmat trucks equivalent to whatever is required of those morons at the airport.
This accident had the afternoon rush messed up horribly as the accident happened at ~2:00 PM. I remember smelling the smoke, not thinking much of it, untill I heard on the radio what the cause was, then getting caught in the traffic trying to bypass the closed road (both directions of 95 were closed) and I was over 20 miles away, north of the accident, traveling north.
Speculation at the time was speeding and asleep at the wheel as causes, never did hear the official verdict.