Canadians stranded after bridge splits amid intense cold
Canadians stranded after bridge splits amid intense cold
(OP)
Canadians stranded after bridge splits amid intense cold
http://www.theweathernetwork.com/news/articles/int...
http://www.theweathernetwork.com/news/articles/int...
Bill
--------------------
"Why not the best?"
Jimmy Carter





RE: Canadians stranded after bridge splits amid intense cold
It also read they don't know what happened. So much for media getting the story.
RE: Canadians stranded after bridge splits amid intense cold
Speculating here, but is it possible the slide bearing didn't have any uplift resistance?
RE: Canadians stranded after bridge splits amid intense cold
In 1985, Professor Henry Petroski published a book titled, "To Engineer is Human: The Role of Failure in Successful Design" (which I highly recommend) where he talked about, among other things, why it is that there has always been, and will continue to be, bridge failures particularly when a new style has started to gain popularity, but generally only one example of a failure will occur. This is because (to paraphrase the good professor) "When it comes to designing a new style bridge, since virtually all bridges are paid for with taxpayer money, in order to reduce costs, safety factors for these new and radical designs will be reduced until there's a failure, at which point the engineers will go back to the last example that did not fail and it will thus become the minimal standard going forward."
In fact, at the end of the chapter covering bridge failures in the above mentioned book (the cover of which shows a bridge failing, the infamous Tacoma Narrows Bridge), Petroski predicted that with respect to the newly introduced 'cable-stayed' designs, that is was just a matter of time before we would see at least one significant failure of this type of bridge.
Now I'm not sure that we could call this Canadian incident a "significant failure", but in terms of the potential impact on the traffic, both commercial and private, on the Trans Canada Highway, to say nothing of the impact on US 28, the primary East/West (and almost all two-lane) highway across the UP (Upper Peninsula) of Michigan, which was mentioned in the news item as being the only practical alternative route, this could be a long remembered failure. And with this being winter, anyone familiar with the UP (I lived there for six years) knows that with lake-effect snow coming off of Lake Superior, that the Trans Canada Highway, despite being further North, is a much less treacherous route this time of year (see image below where green shows approximately where the Trans Canada Highway runs versus the red which is basically the route US 28, shown during what is called a 'lake effect' snow storm):
Some interesting links:
https://en.wikipedia.org/wiki/Henry_Petroski
http://www.amazon.com/gp/product/0679734163/ref=as...
John R. Baker, P.E.
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RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
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RE: Canadians stranded after bridge splits amid intense cold
http://www.chroniclejournal.com/news/national/dama...
I also found this:
Harvey said the bridge has only been open for about two months ago and was the largest most expensive bridge project ever undertaken in Ontario.
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
TTFN
I can do absolutely anything. I'm an expert!
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RE: Canadians stranded after bridge splits amid intense cold
Here is a little. It looks like they are in need of a lot more study. Now this is a good time for Canada to instrument this one if it is not already so equipped.
http://shm.sagepub.com/content/10/5/523.short
CONCLUSIONS
Based on the measurements taken on Ai-Lan Bridge from September of 2010 to
date, the modal frequencies of 18 cables and the temperatures of air and different
structural components are analyzed and cross-examined in this paper. The results
clearly indicate that temperature is the major environmental factor to cause the
variation of cable force. A simplified model proposed in this study also demonstrates
its effectiveness in correlating the variation of cable force with an effective temperature
variation simultaneously considering the temperature effects from the pylon, girder,
and cable. With this progress, a structural health monitoring methodology mainly based
on the identified cable frequency from measurements will be further explored and
applied to Ai-Lan Bridge in the near future
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
Here is the link showing the curve. Seems like north side is worse, maybe due to being warmer due to more sun exposure on the slab per the photo.
http://www.cbc.ca/news/canada/thunder-bay/nipigon-...
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
On another note:
Business is probably quite good at Tim Hortons about 2 miles west of the bridge. (Tim Hortons, A Canadian version of Starbucks)
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
This link shows the open bridge, a two land bridge, not divided highway. Note the weights on one and to "hold it down"? I guess the design could act like a "teeter-todder" otherwise.
http://www.tbnewswatch.com/
RE: Canadians stranded after bridge splits amid intense cold
Again, I think it will be determined that with this style of bridge, cable-stayed, that the difference in the lengths of the cables and thus the difference in the absolute contracting/shortening of the individual cables due to extreme cold temps, one can clearly see from looking at Ingenuity's longitudinal diagram how it is that this could cause the roadbed to bow up at the ends due to the uneven stress in the cables creating a bending moment in the structure of the span.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
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Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
The politicians went into a panic. They wouldn't allow anything that could be said to be "Ramping Up" Canadian seperatism.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
thread507-401708: Ontario Cable Stay Bridge Failure
Keith Cress
kcress - http://www.flaminsystems.com
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Canadians stranded after bridge splits amid intense cold
I wonder if they have designed / tensioned the cables to handle the full weight of the bridge, but been caught out because there is only half of it built so far??
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
http://www.theglobeandmail.com/news/national/engin...
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
It looks like the grade of the road deck goes one way on the abutment, and the relaxed bridge grades the other way now that it's "popped up".
That tells me that the stay cables on the bridge centerline are shorter than the cables used for the sides.
What are the chances that the centerline stay cables were installed on the side?
(pretty unlikely, I'm sure...)
STF
RE: Canadians stranded after bridge splits amid intense cold
The twist may come from the anchorage on that abutment only failing catastrophically on one side, not necessarily relating to the length of the cables in and of themselves. Potentially the left side gave way, which caused further failure in the right side which is still somewhat constrained to the abutment.
RE: Canadians stranded after bridge splits amid intense cold
"•We are able to move forward with construction at this time as we are confident that the recent issues will not reoccur. The temporary repair has been reviewed by an independent engineering firm and found to be appropriate. The bridge is safe for the travelling public.
•Testing of the bolts continues at the two independent labs and work is ongoing to determine the cause of the failure. Once a cause has been determined, the information will be made public and posted here."
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
http://www.tbnewswatch.com/News/388441/Nipigon_Riv...
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
http://www.mto.gov.on.ca/english/highway-bridges/u...
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
The irony now is that The Ordre des ingénieurs du Québec has recently lost its ability to self-regulate, which is the first time I can recall that happening to a professional body in Canada.
RE: Canadians stranded after bridge splits amid intense cold
That's the opposite of the trend in Alberta. What's happening in Quebec?
STF
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
STF
RE: Canadians stranded after bridge splits amid intense cold
https://www.apeg.bc.ca/getmedia/08003931-f44b-4d77...
Here's the related APEGBC article on the issue:
https://www.apeg.bc.ca/News/Articles/Regulatory-Bo...
RE: Canadians stranded after bridge splits amid intense cold
Excerpt: ...Motion demanding the removal of the Executive Committee and director general...
Apparently the old director(s) are suing the new directors, and it's a "circus" in the words of many members.
STF
RE: Canadians stranded after bridge splits amid intense cold
http://www.mto.gov.on.ca/english/highway-bridges/n...
tl;dr - the bolts were not faulty.
The 10 key findings can be found here in the executive summary:
http://www.mto.gov.on.ca/english/highway-bridges/n...
RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
John R. Baker, P.E. (ret)
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RE: Canadians stranded after bridge splits amid intense cold
RE: Canadians stranded after bridge splits amid intense cold
Do I understand that it was the repeated stretching and relaxing of the bolts that led to failure and if the bolts had been tighter they would not have relaxed and would have held?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Canadians stranded after bridge splits amid intense cold
High strength bolts is pretensioned to 0.7 times of the minimum tensile strength of the bolt. That means the tension in the bolt does not change if the uplift load from the cables is less than the sum of the bolts pretension. Also fatigue failure does not occur if the stress range is less than some amount or the stress cycle is less than certain times.
possible explanation of the failure is that the cable contraction force overcome the structure weight and bolts tension, then pull the deck up.
RE: Canadians stranded after bridge splits amid intense cold
Yes, the fact that the bolts were not tightened was one factor. Flexure within the joint with resultant prying was another.
RE: Canadians stranded after bridge splits amid intense cold
Bill
Bill
--------------------
"Why not the best?"
Jimmy Carter