New Analysis Confirms Why the Skagit River Bridge Collapsed
gizmodo.com
gizmodo.com
I am reminded of the half-assed measures that were taken to mitigate the risk of DC10 cargo doors blowing open, prior to the Turkish Airlines crash in Paris. Am I missing something here?
They just need to make sure that the drivers understand that the height limit is lower in the outer lanes.
make sure that the drivers understand
"Overheight must turn" means to virtually all "IF you are Overheight you must turn". Obviously that driver doesn't think he is overheight.
Change it to "Warning: Overheight truck detected in this lane" (with proper lights/arrows pointing to lane). And blink red as well.
The truck driver doesn't realize the sign is only on when he is there, he never sees it when it's off, he has no idea it's illuminated specially for him.
This is government saying "We did something", while doing nothing.
And this sign is above even the traffic lights. Even someone glancing at the colors would not see this.
What they should do is lower the sign to the height of the bridge - so people hit the sign (or something dangling from it).
But that would require government admitting that people hitting the bridge is their fault, and not stupid drivers.
http://www.wsdot.wa.gov/data/tools/bridgeclearance/
Someone driving an oversize load can reasonably be expected to check their route for clearance. It's not the same situation as some guy trying to find Taco Bell in his RV.
NYC takes the cake for inaccurate bridge height signs, though. Some bridges have signs indicating 12'9" or lower clearance when standard 13'6" trucks can clear them easily. It's a complete mystery why they can't mark them correctly. It's been this way for decades (literally).
About an hour and a half later, we established that the road had been recently re-paved and no one was exactly sure what the height was. Backing up to the nearest intersection was not an option because there were none close by and turning the tractor-trailer around was impossible. The cops were cool about it and suggested that I creep forward very slowly and see if I'd fit. I was able to do this and stop just as the trailer reached the bridge. I got out of the cab and climbed up behind the tractor to have a peek and had about an inch to spare. I went for it, very slowly, and made it under. No fun but I did get a cool photo as a memento: http://i.imgur.com/64uYu2z.jpg
I took a different route on the way back of course!
The elevenfooteight bridge now has a traffic light which goes red and stays red on detecting an overheight vehicle, with a lit-up sign saying "OVERHEIGHT MUST TURN". It's still getting hit by overheight vehicles.
And then there's the lengths that had to be gone to in Syndey to stop overheight vehicles entering tunnels:
The 11'8 bridge does indeed seem a lost cause as far as preventing people from ruining their overheight vehicles. But the problem for the bridge has been solved: they installed a beam in front of the bridge which takes the impact.
The same sort of thing could be done with this bridge. Install a sturdy beam ahead of the structural bits. You won't stop people from driving overheight vehicles onto the bridge, but you will stop them from destroying the bridge in the process.
I guess you could have a mechanism to raise the warning beam and only activate it after direct communication with the driver.
That's sort of the other way of looking at the problem. The bridge isn't overbuilt enough.
If the bridge collapses, other vehicles can be damaged, or people killed. Especially if it's carrying a road or railway.
Example from last week: http://www.bbc.com/news/uk-england-kent-37207487
Er, that's less than half the recommended distance. How did the copy editor let that through?
I've got a pretty awesome picture of me and my son standing in front of that empty section of bridge from the detour route. They essentially routed I-5 traffic into the town and across another bridge. If I had to guess, the stores in that area probably made more money during the detour...
ON THE ROAD TO SUCCESS,
THERE ARE NO SHORTCUTS.Common fucking sense.
The correct engineering solution is to have diversity of designs, including an 'open top' bridge near by, which can serve the other cases as well as critical backup traffic during the failure.
You might note that most of the preventative measures outlined do not modify the design of the bridge, but focus on actually keeping records that track the more critical /minimum/ clearance value, as well as more accurately detecting and reporting to the traveling 'over-sized' vehicle that an abort condition has been reached.
No, it isn't, and this is one of the problems when the "general public" comments on engineering things. It's not that people aren't capable of understanding; they lack the experience to understand why something is the way it is.
Someone on /r/seattle[0], where this was recently posted, put it more politely than I:
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It's because that extra two feet can be valuable when carrying oversized loads. Frankly, this all falls on the driver of the oversized vehicle, the driver of the pilot car, and the hauling company.
- The driver of the oversize vehicle is responsible for knowing his load height. A hauler I've worked with before has it in their manuals that the driver must personally measure the load if there is any question. That driver must also stay far enough back of the pilot car to stop in case of a problem.
- The driver of the pilot car fucked up royally by missing the sound of the height-verification antenna hitting the bridge. That is a massive error that should see that pilot car driver drummed out of the industry.
- The hauling company erred drastically by not pre-running the route, or at least the low clearance segments, to verify where the clearance exists. That is "oversize hauling 101."
The article says the state "rubber stamped" an oversize permit. No, they didn't. The hauler certified that the hauler had pre-run the route. It is required that the hauler state that the route has been verified when the permit is issued.
"It is the responsibility of the permit applicant to check, or prerun, the proposed route and provide for safe maneuvers around the obstruction or detours as necessary."
- WSDOT bridge clearance tool (http://www.wsdot.wa.gov/data/tools/bridgeclearance/)
0 - https://www.reddit.com/r/Seattle/comments/50167q/new_analysi...
The Oversized truck should also have an electronic map, which captures cautions regarding height speed issues along every part of the trip.
Simple technology, with a bit of process, could eliminate about 95% of these errors that likely exist today.
Of course, that 5% will still bite from time to time.