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Cracks in Sherman Minton Bridge

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?

RE: Cracks in Sherman Minton Bridge

I live in Louisville and am familiar with *some* of the particulars.  I can tell you that the people who have the good information generally cannot discuss it publicly.

If you have any direct questions, I can see if I can turn up some answers.

RE: Cracks in Sherman Minton Bridge

Why a big secret?? I would think they would want people to know, so they would press to get it fixed, replaced, etc.

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

The big secret is related to the blame game.  I am sure that there will be politic-ing come election time as to which party allowed this to happen.

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

It is not an issue of "secret".  Any type of investigation of this type requires careful analysis and study.  That study involves hiring engineers to do the study and in any competent contractual relationship you have a duty to your client to provide them with your results only after they have been checked and verified.

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

I-64 bridges seem to have been a problem in recent years...

Mike McCann
MMC Engineering

 

RE: Cracks in Sherman Minton Bridge

http://www.courier-journal.com/article/20110921/NEWS02/309210071/1001/More-cracks-found-Sherman-Minton-Bridge?odyssey=mod|newswell|text|Home|p

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

ACI is having its fall convention in Cincinnati next month.  I just thought I should point that out.  

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

TXStructural,

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

It is also that in the mind of the common people buildings and infrastructure is something that should last forever ... at no expenses, preferably, of course.

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

(OP)
So, it sounds like the initial (2-1/2") crack found was in a gusset. I wonder if it was found due to enhanced inspections since I-35 or if it was found by happenstance. Years ago, a crack in a CTA bridge in Chicago was found just because a structural engineer happened to see it on his morning commute.

RE: Cracks in Sherman Minton Bridge

ishvaaag, the only thing you left out were the demi-gods at the state DOT's.  Their reason for existance is to assure that any repairs to the monumen . . . bridges must be accompanied by many worshipful committee meetings consisting of many demi-god . . . DOT engineers.  Then they must insure that there is at least $200,000 spent on this sacri . . . repair.  "And the state of [insert your state here] just doesn't have that money available during these hard times"

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

Duwe6,

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

Gotta object to subsurface cracking -- doesn't seem to have a 'mechanism' to cause it, other than stress-concentrations due to major weld defects.  Flexural cracking emanates from the surface.  Thus a [relatively] fast MT using dry-powder will find bridge cracks.  And the earlier they are found, the smaller and easier to fix they are.

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

(OP)
Fegenbush--that is interesting about the construction material being T-1. And it concerns me, since the repairs will most likely start at the outset of winter, which makes me think the pre-heat procedures more difficult to carry out at low ambient temperatures.

RE: Cracks in Sherman Minton Bridge

Wow, Duwe6, what a varied post.  So you're one of those guys who paints DOT's as over conservative until the bridge comes down egh?

RE: Cracks in Sherman Minton Bridge

Duwe6,

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

Second that wow.  Most of the DOT engineers I know really want to keep bridges safe with a minimum of disruption to the public.  Disruption to the public makes their lives miserable.  It's hard to be in the position of having to decide whether a defect warrants bridge closure.  Some erring on the conservative side seems a good idea when the bridge is non-redundant.

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

"ACI is having its fall convention in Cincinnati next month" - which will give them the opportunity to promote concrete bridges

 

RE: Cracks in Sherman Minton Bridge

Bridgebuster....   and that's a good thing and good timing too, because concrete bridges don't have any cracks which can be welded over and hidden.    smile

RE: Cracks in Sherman Minton Bridge

but it's easier to fix a steel bridge  

RE: Cracks in Sherman Minton Bridge

You don't have to fix a steel bridge ever - they do not reproduce.

Mike McCann
MMC Engineering

 

RE: Cracks in Sherman Minton Bridge

That's a dog of a post.

RE: Cracks in Sherman Minton Bridge

Henny Youngman is alive and well

RE: Cracks in Sherman Minton Bridge

Quote (JAE):

Taking results public before they have been checked, peer reviewed, etc. is simply stupid.
....and in most states, will get you a misconduct citation from the board...or more.
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

You know, the subbject here has been mainly highway bridges.  That's all well and good.  

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

My theory would be that a railroad bridge is stouter to begin with and undergoes far less cycles than a bridge carrying vehicles/trucks.

RE: Cracks in Sherman Minton Bridge

Railroad bridges tend to be more stiff(no pun intended but say it anyway Mike smile )than highway bridges, which would help with fatigue.

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

Perhaps, and I can understand the number of cycles issue.  However there is another, in my opinion, and that is the live load to dead load issue.  The engines alone are over 200 tons, and with four carriages with two wheels, puts 50,000 pounds on each axle.  Admitedly the car axles see nowhere near this.  In a train of 100 cars, there could be over 400 axles that would pass.

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

I've inspected 100's of bridges and have also seen a lot of failures waiting to happen. Some bridges have more internal redundancy than we're aware of, maybe some others have guardian angels.

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

Mike, that's a common misconception.  The magnitude of applied load is not what matters, it's the resulting stress in the member that matters....combined with the number of cycles.  Fundamentals of fatigue design. Rail bridges are far stiffer, for much higher loads, hence lower cycle stresses.

RE: Cracks in Sherman Minton Bridge

Just an update for anyone interested.  There was an estimate given on the repair time of 6 months.  That would put the completion of the project near the end of March 2012.

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

(OP)
Thanks for the update, fegenbush.

RE: Cracks in Sherman Minton Bridge

(OP)
Indianapolis Star reports that a contract for $13.9 million has been let with a completion time for mid March. 3 million pounds of new steel apparently are to be placed.Sounds like an upgrade in addition to a repair.

RE: Cracks in Sherman Minton Bridge

Sounds like somebody at TnDOT is smart.  Taking this opportunity to upgrade an old bridge shows me good planning.  3MM lbs of new steel sounds like a major upgrade or a piecemeal replacement.

RE: Cracks in Sherman Minton Bridge

Why give "TnDOT" the credit?  This bridge spans the Ohio between Indiana and Kentucky.

RE: Cracks in Sherman Minton Bridge

(OP)
The Louisville C-J has a simulation on their website showing plates being riveted to the bottom longitudinal member. Will the repair actually be done like that, or will the plates be welded?

RE: Cracks in Sherman Minton Bridge

Definitely no welding. That was part of the original problem, welding of the old T1 steel in a tension tie.  Not revited either, bolted.

RE: Cracks in Sherman Minton Bridge

Since ASME SA514 requires PWHT for pressure vessels, I can assume that it is similar for other welds as well.  It wouldn't surprise me that they would bolt the repair plates to avoid that issue.

RE: Cracks in Sherman Minton Bridge

bridgebuster,
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

woodman88,

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.

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