24.5 % of Nation's Bridges longer than 20 feet "Structurally Deficient"

[competentone]

Originally Posted by Gogar

When was the last bridge collapse of note 'before' this one?

If there's 600,000 bridges in the U.S.A., and one bridge collapses every (x) years, and (y) is the number of cars that pass over those bridges, (in the hundreds of millions each day, I bet), and the last bridge collapse was in 19xx,

C'mon, math majors. Help me out. But I can tell you I'll take those odds.

Unfortunate tradgedy? yes. Worry? not much. I bet you're as likely to win PowerBall.

Of course, we can only assume that more and more of our 20th century bridges will collapse in time as they get older and older.

Good points -- and I'm betting that the construction work on the bridge is going to be a big contributing factor in this collapse.

In an earlier thread here, I speculated (based upon the early reports I had heard about the construction) that "destructive resonance" -- resulting from the jack-hammers being used during the repair work -- could be a factor in the collapse. Since then, I've heard additional interviews from people living/working in the vicinity of the bridge; I'm hearing additional comments about the "noise, vibration and shaking" occurring during the jack-hammering.

There may have been corrosion, stress fractures, and a lack of redundancy for carrying the stress loads on the bridge -- which will all be factors in the collapse -- but I'll be expecting that the "triggering factor" in the collapse will be the build up (and destructive release) of energy in the structure from the use of jack-hammers in the repair work on the bridge.

[widgeon13]

Media says it was rush hour traffic, while it was rush hour, the traffic was only flowing single file to my understanding. Had it really been normal traffic flow, all lanes, many more would have died. Is this true that traffic was single file?? I would like to hear from someone who really knows what the traffic situation was on the actual span.

Try to shut down a bridge for any reason and public will ***** about that endlessly.

Considering no other bridges have fallen in recent years I think we are doing well. Why weren't people complaining about this before, no one cares until one falls and then everyone is on the bandwagon complaining and placing blame.

[stomachmonkey]

Originally Posted by competentone

Good points -- and I'm betting that the construction work on the bridge is going to be a big contributing factor in this collapse.

In an earlier thread here, I speculated (based upon the early reports I had heard about the construction) that "destructive resonance" -- resulting from the jack-hammers being used during the repair work -- could be a factor in the collapse. Since then, I've heard additional interviews from people living/working in the vicinity of the bridge; I'm hearing additional comments about the "noise, vibration and shaking" occurring during the jack-hammering.

There may have been corrosion, stress fractures, and a lack of redundancy for carrying the stress loads on the bridge -- which will all be factors in the collapse -- but I'll be expecting that the "triggering factor" in the collapse will be the build up (and destructive release) of energy in the structure from the use of jack-hammers in the repair work on the bridge.

Combine it with potential harmonic resonence from slow moving (low RPM) vehicles.

[Tobra]

The bridge was a poorly designed, welded instead of riveted together structure. I have read the poor balance of the load, all the weight sitting still in two lanes rather than moving in all lanes.

They have been very rare in the past, but we are going to begin seeing more failures.

[cairns]

Well it's clear that politicians get their names put on new bridges not on fixing the old ones. Of course they're all coming out from under their rocks now and pointing fingers at other politicians- but they're not going to change the earmarks, misappropriations and public posturing that got us here.

And as usual the media are quick to point out all the bad things government is doing- after the fact. Without actually reporting on the processes that lead to disasters like this- much less discussing why they failed to report on aging infrastructure in the past. After a few weeks, the story will fade away and they'll have something something else to bleed and lead and help sell their papers.

I'm sure that after our badly outdated Air Traffic Control Infrastructure leads to a spectacular collision killing hundreds (or thousands) the "reporters" will let us know how bad it is...the politicians will blame other politicians and the cycle will repeat itself...and of course the same tiresome liberals will blame Bush & Iraq for it all.