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Rural Bridge Collapse Immediately After Opening 16
- Thread starter Shotzie
- Start date
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1
- #41
BridgeSmith
Structural
From the warning linked above: "...unfortunately something under the riverbed failed, that could not have been anticipated."
Really? No way to anticipate several feet of settlement? Heck, a simple rod driving test would have likely sufficed to tell them that much. An actual subsurface investigation by a qualified geotech could probably have estimated it within an inch or less. Am I right geotech guys?
Edit: Obviously, I don't mean estimating the 4' of settlement to an inch or less, but the settlement for a properly sized foundation with adequate capacity...
Really? No way to anticipate several feet of settlement? Heck, a simple rod driving test would have likely sufficed to tell them that much. An actual subsurface investigation by a qualified geotech could probably have estimated it within an inch or less. Am I right geotech guys?
Edit: Obviously, I don't mean estimating the 4' of settlement to an inch or less, but the settlement for a properly sized foundation with adequate capacity...
charliealphabravo
Structural
If helical piers were used then that raises more questions. Helical piers imply a pinned connection below the waterline as opposed to a continuous pile with base fixity. Lateral resistance could be much less in the absence of a pile cap system and battered piers. Were the original piles pulled up thereby disturbing the subsurface integrity? Were the piers placed adjacent to the original piles thereby incorporating an eccentric load on the piers? How was bearing capacity determined? A correlation with torque may not be sufficient in the absence of geotechnical guidance.
BridgeSmith
Structural
By my estimation of the sophistication of this operation, I seriously doubt they would know what a helical pier/pile was, much less have the knowledge or equipment to install them.
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2
- #44
Charlie, I agree the torque is only a part of the problem. I am not totally sold on your pin theory. Short term, yes, but long term much of the helix disturbance settles. This failure was short term, so that very well could turn out to be part of the problem. That said, the failure appears to be largely a vertical settlement, so it seems to me that the soil block around the helix(s) sheared and then the bridge settled until segments started falling off. The resistance contribution from shaft resistance for vertical loads is usually virtually inconsequential for these small diameter piles.
There will be thousands of hopper bottom grain bins near this bridge that are supported on screw piles. That is farming country, and screw piles are cost effective, fast and practical for the clay soils. The common load to the leg of many of those bins is between 40,000 - 100,000lb. It is very common to put a single pile at each leg. They will have contractors that have a basic (maybe good) understanding of screw piles. The unique aspect about bins is they see the full design loads many times each year, unlike other structures that may or may not see the full design load. The mere size of the rig needed to reach out to install the pier piles suggests they had a rig that should have been capable of generating reasonable torque values.
There will be thousands of hopper bottom grain bins near this bridge that are supported on screw piles. That is farming country, and screw piles are cost effective, fast and practical for the clay soils. The common load to the leg of many of those bins is between 40,000 - 100,000lb. It is very common to put a single pile at each leg. They will have contractors that have a basic (maybe good) understanding of screw piles. The unique aspect about bins is they see the full design loads many times each year, unlike other structures that may or may not see the full design load. The mere size of the rig needed to reach out to install the pier piles suggests they had a rig that should have been capable of generating reasonable torque values.
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3
- #45
Clearly a Diode Bridge.
You can cross it but only in the one direction.
Keith Cress
kcress -
You can cross it but only in the one direction.
Keith Cress
kcress -
BrianPetersen
Mechanical
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2
- #49
Rubes in Hickville build a bridge and it collapses.
College professor in Italy builds a state-of-the-art bridge and it collapses.
Professional bridge engineers in Florida build a bridge and it collapses.
Rubes in Hickville fail to do soil investigation and the bridge sinks.
Experienced geotechnical engineers in S. Padre Island spend thousands on soil investigations and the building sinks.
Experienced geotechnical engineers in California spend gazillions on soil investigations and the building sinks.
I'm not sure what the moral is in all this, though.
Edit: Now that I think about it, these folks accomplished a better safer quicker cheaper and less painful failure, there should be some kind of award for that.
College professor in Italy builds a state-of-the-art bridge and it collapses.
Professional bridge engineers in Florida build a bridge and it collapses.
Rubes in Hickville fail to do soil investigation and the bridge sinks.
Experienced geotechnical engineers in S. Padre Island spend thousands on soil investigations and the building sinks.
Experienced geotechnical engineers in California spend gazillions on soil investigations and the building sinks.
I'm not sure what the moral is in all this, though.
Edit: Now that I think about it, these folks accomplished a better safer quicker cheaper and less painful failure, there should be some kind of award for that.
dik (Structural) said:
It's déjà vu all over again as Canada Press stated that almost a week ago (20 Sep 18 22:23) :
www.canadapressit.com/bridge-that-collapsed-six-hours-after-opening-was-built-without-geotech-investigation-of-riverbed-reeve
Interesting announcement on their website from when the bridge re-opened 2 weeks ago:
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
[URL unfurl="true" said:
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
Hopefully not 4 feet this time!
I think I'll avoid that span for some time.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
I think I'll avoid that span for some time.
----------------------------------------
The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
It looks like a 13-km detour to get to Swan Plain without that bridge, but there does seem to be alternative paths for most people in that RM.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
An act of god is an inevitable, unpredictable, and unreasonably severe event caused by natural forces without any human interference, and over which an insured party has no control, such as an earthquake, flood, hurricane, lightning, snowstorm. Acts of God are insurable accidents and valid excuses for non-performance of a contract.
The reeve of the RM of Clayton, Duane Hicks is obviously not an attorney and obviously confused.
On the one hand, he claims that it was an act of god, which if true would take the Contractor off the hook. The next minute, he claims that the bridge is under warranty and the Contractor will repair/replace at no cost to the community. Both of these statements can't be true.
An attorney would probably advise him to stop speaking about the Contract.
The final outcome of this incident will depend on whatever is in the Contract. Based on the comments made so far by the reeve, one would not have much confidence in his ability to prepare a proper construction contract.
The reeve of the RM of Clayton, Duane Hicks is obviously not an attorney and obviously confused.
On the one hand, he claims that it was an act of god, which if true would take the Contractor off the hook. The next minute, he claims that the bridge is under warranty and the Contractor will repair/replace at no cost to the community. Both of these statements can't be true.
An attorney would probably advise him to stop speaking about the Contract.
The final outcome of this incident will depend on whatever is in the Contract. Based on the comments made so far by the reeve, one would not have much confidence in his ability to prepare a proper construction contract.
Screw piles are ubiquitous on the prairies.
The contractor may have done hundreds of screw piles without a geo-tech survey.
The other piles are still giving good service.
Why not these?
It always worked before.
Bill
--------------------
"Why not the best?"
Jimmy Carter
The contractor may have done hundreds of screw piles without a geo-tech survey.
The other piles are still giving good service.
Why not these?
It always worked before.
Bill
--------------------
"Why not the best?"
Jimmy Carter
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