Cracks in Sherman Minton Bridge
Cracks in Sherman Minton Bridge
(OP)
The Sherman Minton bridge, which carries I-64 across the Ohio river at Louisville, was closed on Sept 9 due to at least two cracks found. Anyone involved in this project?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Cracks in Sherman Minton Bridge
|
RE: Cracks in Sherman Minton Bridge
If you have any direct questions, I can see if I can turn up some answers.
RE: Cracks in Sherman Minton Bridge
Obama is coming to Cincinnati to fight for the jobs bill in front of the Brent Spence Bridge. If that ever were to close, it would be major headache to everyone.
RE: Cracks in Sherman Minton Bridge
Additionally, I think they are trying to avoid people panicing since you know how well the media reports on technical topics (sarcasm).
Finally, you're talking about a city (Louisville) that has been trying to build another bridge for the better part of 40 years. Bridges are a hot button issue and this situation is like throwing gas (petrol) on a fire.
RE: Cracks in Sherman Minton Bridge
Taking results public before they have been checked, peer reviewed, etc. is simply stupid. With this being a public bridge, I'm sure the results will eventually be made public but engineering takes time does it not?
RE: Cracks in Sherman Minton Bridge
Mike McCann
MMC Engineering
RE: Cracks in Sherman Minton Bridge
Skip to 10:13 for anything structurally interesting.
Wow, weld fatigue, how surprising. I would have thought the 2nd street bridge would have been the one to have problems.
I took a grad course in steel fatigue, very frightening. Nobody realizes that cracks are common. There are so many bridges out there that were never designed per good fatigue provisions....and even the ones that are still have issues.
RE: Cracks in Sherman Minton Bridge
They caught this before a serious mishap occurred, and as ASCE has been saying, it is time to spend money on our infrastructure.
RE: Cracks in Sherman Minton Bridge
ASCE is correct in their call that we need to be focusing our energy on maintaining these infrastructure items since it is much cheaper to maintain them than to replace them. You are correct that this was caught before something very bad happened. I would have thought that inspectors would have been covered up with work for years after the I-35W bridge in Minneapolis, but I guess it's not that important to all governments.
RE: Cracks in Sherman Minton Bridge
The long life of buildings and structures instils them such thought; and insecure as every form of life in earth, they usually love the sense of permanence imparted by long-standing structures, through which the species lives a dream of long-lasting life. I once read an article "Architecture vs. Death" along these lines.
So to descend to maintain such big structures is to insult their inmortality, for the gods must never be molested; and if they fall, they do in fight with other gods. There is a lot of primeval thought in the public perception of monumental construction, or overall shape of the city. Those reforming are seen as blasphemous transgressors of divine order, and rarely loved for that.
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
It's just a fatigue crack. Big deal. Close the bridge -- no more 'Live Load'; jack and crib up the affected area -- no more 'Dead Load'. Air-arc out the crack, MT to verify removal, weld up area, MT to verify good weld. Remove cribbing & reopen the bridge. Inspect, using MT, annually for cracking in the similar areas of the bridge. After one or 2 more occurances, develope a 'fix' that will strengthen those sections without making them unduly stiff. Install the 'fix' to all similar areas.
RE: Cracks in Sherman Minton Bridge
I agree, probably fatigue cracking. The problem is that they found, say 6 (made up number) cracks, but they had only completed, say 20% (made up number) of the bridge inspection.
Problem 1:
They are attempting to determine the extent of the damage. This has not been made available as of yet.
Problem 2:
The bridge was made from T-1 steel (NOT T1 tool steel) which is similar to A514. The use of this material in bridges was pretty innovative in the 60's. The gouge and weld method would work well if it were "normal" structural steel, but there are those who question the ability to make the repair and maintain the original strength.
Problem 3:
MT for the annual inspection would not detect the cracks that might form under the surface of the weld. RT would be my recommendation.
I do enjoy the discussion about this issue, since it is relevant to where I live.
RE: Cracks in Sherman Minton Bridge
Sometimes, I have found structural cracking early enough that the grinding for crack removal did not go below T-minimum for that area. We just blended out the excavation, buffed it to remove grinding scratches, put a little paint on it, and went home. DOT bridge engineers want to make everything a MAJOR problem. Most things aren't.
If it's rusting, needle-scale it and brush some zinc-rich primer on it. That approach would have saved the I-35 bridge. Minnesota DOT has records of the thickness loss due to rust of the gusset [side] plate that failed. Yes, it was too thin when it was installed, but watching it rust away, and doing nothing to stop it, was the proximate cause of that catastrophe.
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
With regard to subsurface cracks: I concede that point. I am not a bridge guy. Thanks for the input.
RE: Cracks in Sherman Minton Bridge
Do we really know where the cracks are? Out of plane bending at the floorbeam to tie connection can be an tough issue with this type of bridge. Simple welding of the crack might not be effective for this.
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
Mike McCann
MMC Engineering
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
As for a state DOT over-reacting...well, if they don't find and highlight issues, they get criticized for being unresponsive or negligent. Where life safety is an issue, it is better to use an abundance of caution. If it turns out to be a minor or non-issue, so be it. The only thing lost is a little face and maybe some time.
RE: Cracks in Sherman Minton Bridge
However, I have not seen one railroad local bridge that had more rust hilding it together than rivets. The most recent maintenance on them has been from the painting of the local taggers and that is pathetic in my opinion. I see a lot of maintenance on the rails and ties, but nothing on the bridges.
Mike McCann
MMC Engineering
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
AASHTO (Standard Specs) considers a riveted connection to be a Category D detail (although LRFD lowers it to C) - I don't have AREMA handy to see what they prescribe.
I would agree that the stress cycles in a railroad bridge are lower. In NYC, there are a lot of riveted train trestles in use 24/7. The last elevated train line opened around 1915 and I don't ever recall hearing anything about fatigue cracks.
As an aside, 30 years ago I wrote to the Transit Authority about the deteriorated column rivets on a section of the elevated train I used to take. I never heard back from them; they never fixed anything; but the structure is still standing.
RE: Cracks in Sherman Minton Bridge
In highway bridges, I would contend that the live to dead load ration is much less than a railroad bridge, prompting greater deflections and the need for trusses to limit that.
I still think these bridges are just an failure waiting to happen, especially with little or no apparent maintenance.
Mike McCann
MMC Engineering
RE: Cracks in Sherman Minton Bridge
About 20 or so years a consultant did a study of the Williamsburg Bridge cables - suspension bridge over the East River in NYC - because an inspection indicated broken wires. One conclusion was that the broken wires were still able to contribute to the strength of the cable. Who knows?
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
What you guys may not be familiar with is the time limitation that they are under. The bridge will need to be open by (approx.) April 7. There is a very large fireworks show that closes on of the other bridges across the Ohio River about the 14th of April. It's a big deal around here every year, and they won't be able to close the other bridge if the Sherman Minton isn't open.
So, the drama continues...
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
RE: Cracks in Sherman Minton Bridge
Your comment "As an aside, 30 years ago I wrote to the Transit Authority about the deteriorated column rivets on a section of the elevated train I used to take. I never heard back from them; they never fixed anything; but the structure is still standing."
Reminds me of traveling with an older engineer (30 years ago) under a railroad bridge that steel plates were buckled. I asked him why the bridge was still in use. He said that the old railroad bridges were built for big locomotives and the new locomotives were much lighter that the old ones. They just added additional locomotives as needed for the train load.
Does anybody think/know if this is true? Or was he just playing on my (than and now) inexperience about railroads.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Cracks in Sherman Minton Bridge
I found this on Wikipedia
"During the 1880s, railway bridges were built using an equivalent rating of E20. By 1894, when Cooper presented his standard, he recommended a standard of E40, or four times the E10 standard. By 1914, the standard had increased to E60. By the mid 1990s, the American Railway Engineering Association was recommending E72 (7.2 times the E10 standard) for concrete structures, and E80 for steel structures."
Later, I'll take a look at the NYC Transit specs to see if anything has changed. My guess is that the car loads are about the same now as they were a century ago.