[Newsbot]

Title: Washington police blame bridge collapse on Alberta trucker
Category: Misc CDN
Posted By: Robair
Date: 2013-05-24 13:42:05
Canadian

[Robair]

More details here: http://news.yahoo.com/horrified-trucker ... 33698.html

[raydan]

If the bridge was in such bad shape that a truck could take it down, the bridge should have been closed.

[jeff744]

raydan raydan:

If the bridge was in such bad shape that a truck could take it down, the bridge should have been closed.

They need to pass the blame off to someone so their reckless policies don't come back to haunt them.

[Thanos]

Any collision that didn't also completely destroy the truck wouldn't have knocked a bridge down, not if the bridge were in any acceptable shape to be safely used. If any impact that barely dented a vehicle was sufficient to cause a collapse then that bridge was going to fall anyway, and most likely sooner not later.

[BartSimpson]

http://www.cbsnews.com/8301-201_162-575 ... r-trailer/

Blame Canada!

(Not really )


The thought is that the truck was too tall....

$1:

Initially, it wasn't clear if the bridge just gave way on its own. But at an overnight news conference, Washington State Patrol Chief John Batiste blamed it on the too-tall load. The vertical clearance from the roadway to the beam is 14.6 feet.

Hopefully the new bridge will be built to the higher standard of 16 feet or it will simply be built as an open deck bridge without any clearance limitations at all.

That said, I don't blame the driver as he navigated a number of other bridges just fine. It was only this one that literally came up short.

[Robair]

There's more details in that second link. He had all the permits, there were no signs ahead of the bridge stating the overhead clearance, and it sounds like he picked off a whole row of overhead trusses.

[Xort]

14.6+ feet is oversized but that's not hugely oversized.

I wonder what the trucks load was messured at.

Lucky no one died. Sorta a crappy way to go about making road upgrades.

[DrCaleb]

Thanos Thanos:

Any collision that didn't also completely destroy the truck wouldn't have knocked a bridge down, not if the bridge were in any acceptable shape to be safely used. If any impact that barely dented a vehicle was sufficient to cause a collapse then that bridge was going to fall anyway, and most likely sooner not later.

I was thinking on similar lines. How could one hit on a bridge take it down, unless it was ready to collapse already?

[Robair]

What I read said a number of hits. "Whack, whack, whack whack..." Then kaboom.

[Thanos]

The photos of the remaining segments of the bridge don't show any impact damage at all to the trusses.

[BartSimpson]

DrCaleb DrCaleb:

How could one hit on a bridge take it down, unless it was ready to collapse already?

Through-truss bridges generally don't have a lot of redundancy built into them. Failing one part of the truss is frequently catastrophic. That's why they've fallen into disfavor since the 1950's.

Their advantage is that they can span a distance cheaper than a brute-force plate and girder style bridge but then they're subject to the kinds of failures that plate and girder bridges typically won't suffer except in the most extreme circumstances.

If you want to play with these bridges there's a simple physics engine on the web that's fun to play with:

http://www.bridgebuilder-game.com

[BartSimpson]

Thanos Thanos:

The photos of the remaining segments of the bridge don't show any impact damage at all to the trusses.

The driver probably was in the right lane when he got onto the bridge and then swerved to the left lane as soon as he saw what was happening.

Again, not his fault as the impaired bridge clearance is not noted on the approach to the bridge.

http://maps.google.com/maps?hl=en&ll=48 ... 38,,0,2.45

(Damn! Google Maps already shows the bridge being out! )

http://maps.google.com/maps?hl=en&ll=48 ... 8&t=m&z=14

[xerxes]

BartSimpson BartSimpson:

Thanos Thanos:

The photos of the remaining segments of the bridge don't show any impact damage at all to the trusses.

The driver probably was in the right lane when he got onto the bridge and then swerved to the left lane as soon as he saw what was happening.

Again, not his fault as the impaired bridge clearance is not noted on the approach to the bridge.

http://maps.google.com/maps?hl=en&ll=48 ... 38,,0,2.45

(Damn! Google Maps already shows the bridge being out! )

http://maps.google.com/maps?hl=en&ll=48 ... 8&t=m&z=14

And that's why Apple Maps was the colossal failure that it was.

[BartSimpson]

BartSimpson BartSimpson:

DrCaleb DrCaleb:

How could one hit on a bridge take it down, unless it was ready to collapse already?

Through-truss bridges generally don't have a lot of redundancy built into them. Failing one part of the truss is frequently catastrophic. That's why they've fallen into disfavor since the 1950's.

Their advantage is that they can span a distance cheaper than a brute-force plate and girder style bridge but then they're subject to the kinds of failures that plate and girder bridges typically won't suffer except in the most extreme circumstances.

If you want to play with these bridges there's a simple physics engine on the web that's fun to play with:

http://www.bridgebuilder-game.com

Damn, I'm good.

http://online.wsj.com/article/SB1000142 ... 46190.html

$1:

One Link Proves Bridge's Undoing

MOUNT VERNON, Wash.—The bridge collapse on Interstate 5 that sent two cars into frigid waters of the Skagit River, severing a main north-south artery between the U.S. and Canada, resulted from a semi-tractor trailer tearing into an overhead girder rather than problems with the roadbed itself, officials said.

While state transportation officials said Thursday night's breach wasn't caused by structural flaws, the incident raised new questions about the nation's aged infrastructure. The 1955 bridge is of a through-truss design, common for the era, that lacks the redundancy of more-modern spans—meaning that severing one truss can cause the entire bridge to collapse.