Canadians stranded after bridge splits amid intense cold 3

[waross]

Canadians stranded after bridge splits amid intense cold

http://www.theweathernetwork.com/ne...ts-brand-new-bridge-strands-canadians-/62165/

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[JStephen]

Another update, also of the "The report hasn't been released yet" sort:

http://www.mto.gov.on.ca/english/highway-bridges/updates/index.shtml

 

[ronbert]

The Order of the Engineer was formed as the result of a Canadian bridge failure.

 

[gwynn]

To be more accurate, it was the Ritual of the Calling of an Engineer and the Corporation of the Seven Wardens that were the result of a Canadian bridge failure - the Quebec Bridge to be exact. The Order of the Engineer came about later after and was inspired by the success of the aforementioned ritual and organisation, not the original bridge failure.

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.

 

[Sparweb]

...lost its ability to self-regulate...
That's the opposite of the trend in Alberta. What's happening in Quebec?


STF

 

[gwynn]

I don't know the details of what is happening in Quebec. Only what was in the email news notification from my local association, which said that they had been placed under temporary government stewardship.

 

[VEBill]

CBC News

 

[jayrod12]

I fear the corruption that we've heard about in Quebec may unfortunately be making its way to engineers.

 

[Sparweb]

Thanks for the update.


STF

 

[gwynn]

Here is a link to the 2015 report that resulted from the original inquest (I am linking the English translation, not the French original). If it's a members only document, I can dig up the link from Manitoba which might not be. APEGA seems to not have a direct link to it.

https://www.apeg.bc.ca/getmedia/080...7628c5d3/RapportPiloteLamontagne_Eng.pdf.aspx

Here's the related APEGBC article on the issue:

https://www.apeg.bc.ca/News/Articles/Regulatory-Body-for-Quebec-Engineers-Placed-under

 

[Sparweb]

Ouch, they're having a rough time.
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

 

[allgoodnamestaken]

MTO has released a bunch of reports related to this bridge failure.

http://www.mto.gov.on.ca/english/highway-bridges/nipigon-bridge/index.shtml

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/nipigon-bridge/pdfs/ae-exec-summary.pdf

 

[marty007]

It's not my industry, but the executive summary was certainly an interesting read! Thanks

 

[JohnRBaker]

Yes, it does look like it was written for a very broad audience. I did note that item 10 in the list of findings seems to support, to some extent, my comments from 11-12 January.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Shu Jiang PEng SE]

Did not see what the pretension in the suspended cables is in the report. The high possibility is that The contraction thermal load in the cables pull the steel deck/beams up.

 

[waross]

A question for the structural guys;
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

 

[Shu Jiang PEng SE]

To waross

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.

 

[hokie66]

waross,

Yes, the fact that the bolts were not tightened was one factor. Flexure within the joint with resultant prying was another.

 

[waross]

Thanks for the explanations.
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter