| Aug 3, 2007 @ 6:17 AM |
How About that Bridge in Minnesota??? Do you have any like that?
|
|
MusicMonster
Posts: 2,954
|
Video of the actual happening. Some of the most shocking depictions I've yet seen about this..
What an awful disaster!! A very harsh reality!
Since then, they've looked at things here and found 41 bridges just in our local county alone, and I believe it was 1400 throughout the state, that are either structurally sub-standard in some way, or very old.
I have often been on some very high bridges here, stuck in in our horrendous version of Rush Hour, (the ones that wind their way high over 4 or 5 other highways in a tangled pattern that resembles a mound of earthworms from the air), and have felt the bridges shucking and jiving under the pressure, the heavy beating they take, and from all the weight.
It's always disconcerting to be swaying to and fro and vibrating on a bridge that way to say the least, even a little, especially one that high up, and I always feel a sense of relief in getting to the other side. But you always figure, Hmmm, some amount of flex is surely built into such a structure and hopefully those who built it knew what they were doing. But did they? It was a bidding war after all, based primarily on cost.. However, if it were not sound, there could indeed be Hell to pay. And apparently many of them are not so structurally sound. I suspect that situation prevails in several parts of the country.
Have you had any experiences like that around home? Are your local bridges a safe place to be spending your commute time?
-MM 
|
|
  |
|
| Aug 3, 2007 @ 7:32 AM |
How About that Bridge in Minnesota??? Do you have any like that? |
|
eastham
Posts: 6,317
|
I was just reading an article from the newswires that this bridge was declared structurally deficient seventeen years ago. They made some minor repairs, which obviously didn't fix the problem. Shame!
|
| |
|
| Aug 3, 2007 @ 12:03 PM |
How About that Bridge in Minnesota??? Do you have any like that?
|
|
iam7545
Posts: 4,151
|
eastham - the streets and bridges in Baltimore resemble Moscow - and if you have never been there - Moscow's roads and bridges resemble war torn Baghdad! It is pathetic!
|
|
| |
|
| Aug 3, 2007 @ 2:01 PM |
How About that Bridge in Minnesota??? Do you have any like that? |
|
steveemac
Posts: 2,336
|
From anopther thread:
On December 13, 2000, two girders in a three-girder approach span on the Milwaukee Harbor I-794 (Hoan) Bridge failed. A major effort to determine the cause of the failure was initiated by Wisconsin DoT. The failure analysis effort involved Lichtenstein Engineering Associates, Lehigh University, The Federal Highway Administration, The University of Michigan and Northwestern University's Infrastructure Technology Institute. The failure analysis utilized the wide range of experience and expertise of bridge experts from the above mentioned institutions and involved both analytical and experimental techniques including metallography, 3-D finite element modeling, materials testing, and load tests. The conclusions of this massive effort indicate that the primary cause of the failure was a combination of very high tri-axial stress combined with lowered material properties caused by low temperatures. The high tri-axial stress results from the geometry of the connection detail used for the lateral bracing system for the Hoan Bridge. The resulting high stress in the "web gap" of this detail produces a condition where a ΒΌ-inch crack becomes un-stable and can lead to explosive failure.
Besides the Hoan (which nobody saw coming), we are lucky NOT to have had a Minneapolis-type disaster in the tall flyover ramps of the Marquette Interchange-the poobahs of state government have been saying that it needs to be replaced for the better part of the last quarter century, but nobody wanted to pay for it-and in Wisconsin, if one is an upstate legislator, one can make political "hay" by simply blaming Milwaukee for everything from higher taxes to the decline of Western civilization to cooties...also, the Sixth Street Viaduct was over 90 years old when it was finally replaced in 2001-for many years prior to it's replacement, it was reduced from four lanes to two, because it was feared that it could no longer bear the weight of four lanes of traffic.
|
| |
|
| Aug 3, 2007 @ 2:55 PM |
How About that Bridge in Minnesota??? Do you have any like that?
|
|
grumblebear
Posts: 10,471
|
There are thousands of bridges Nation wide that are rated as bad, or worse than our freeway bridge that just collapsed... The news story I was watching claimed 600 billion in repair, or replacement costs.... and 20 years to fix....
but the scariest one was that 1 bridge a week collapses in America, but most are small back country bridges.....
|
|
| |
|
| Aug 7, 2007 @ 9:37 PM |
How About that Bridge in Minnesota??? Do you have any like that? |
|
MusicMonster
Posts: 2,954
|
As mentioned earlier grumblebear, we have several of our freeway bridges here that jostle around quite a bit when we are crossing them, especially with other traffic close by. You feel them bouncing and swaying underneath you. I just pretty much thought that's how it must be, until they judged so many in this state to be inadequate right after this tragedy. Something like 41 of them in this county alone.
I didn't think too much of it, until they were saying on CNN that people should have probably recognized that there was something wrong because the bridge in MN was in felt to be in some kind of motion. When feeling that, it has always made me apprehesive, but I just wrote it off as not knowing enough about bridge construction to fill a thimble. But now I'm not so sure. Perhaps such bridges AREN'T suppose to bounce and sway that way, after all???
I wonder if anyone else has made note of that before in their own locales?
-MM 
|
| |
|
|
|
|