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40-ton timber arches collapse in Hickory, NC 35
- Thread starter bugbus
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- #184
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The Elders of this Hick(ory) town Pined Fir a way to Spruce up a Trunk Route. They twigged on to the warped idea of a Red-wood arch. When the arch felled itself (tim-berrr!) they could not beleaf it. They could knot leaf the lumber there, so to get the town out of the woods it was replaced by a material with more structural integritree.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
Alistair_Heaton
Mechanical
It was good as these things go visually. It had different features depending on the angle.
Per say I think it could be engineered to work. Might not be as clean on the joint points but 95% of it would be the same.
But now the political legal wheels are turning it won't happen.
Per say I think it could be engineered to work. Might not be as clean on the joint points but 95% of it would be the same.
But now the political legal wheels are turning it won't happen.
Alistair_Heaton
Mechanical
It wouldn't take that much to get I viable either. I agree it did look good.
Alistair_Heaton
Mechanical
I liked the wood one because it was the fish rune and changed with the aspect that you looked at it.
I suspect that it was a short cut by the building contractors that killed it.
I suspect that it was a short cut by the building contractors that killed it.
LittleInch
Petroleum
I think what it needed was for one of the spars to be complete and unchanged and then the other two timbers bolted to it giving the impression of a wooden single cross piece. Doing it as four pieces all connected together in one location was the error there IMHO. That is after the person who drew it without giving it a thought as to how it was going to be made....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
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1
- #195
Electronbelt
Industrial
Update on the situation...
One of the engineering firms brought on to investigate the collapse (by the legal defense team representing the contractor that assembled the structure) has released a preliminary report of their investigation into the failure.
Greensboro News & Record has published an article here on the topic:
[URL unfurl="true"]https://greensboro.com/news/state-and-regional/why-did-the-hickory-arches-fall-report-cites-faulty-design/article_ca281b3b-9cd6-5978-a6e6-3b8668592606.html[/url]
And included the report in PDF form available here:
[URL unfurl="true"]https://bloximages.newyork1.vip.townnews.com/greensboro.com/content/tncms/assets/v3/editorial/4/f3/4f3c3a1d-152e-5e27-9bc4-3390ac47eeb7/62a51df1b05e4.pdf.pdf[/url]
The report is an interesting read and is harmonious with a lot of the structural and design observations made within this discussion thread.
One of the engineering firms brought on to investigate the collapse (by the legal defense team representing the contractor that assembled the structure) has released a preliminary report of their investigation into the failure.
Greensboro News & Record has published an article here on the topic:
[URL unfurl="true"]https://greensboro.com/news/state-and-regional/why-did-the-hickory-arches-fall-report-cites-faulty-design/article_ca281b3b-9cd6-5978-a6e6-3b8668592606.html[/url]
And included the report in PDF form available here:
[URL unfurl="true"]https://bloximages.newyork1.vip.townnews.com/greensboro.com/content/tncms/assets/v3/editorial/4/f3/4f3c3a1d-152e-5e27-9bc4-3390ac47eeb7/62a51df1b05e4.pdf.pdf[/url]
The report is an interesting read and is harmonious with a lot of the structural and design observations made within this discussion thread.
Electronbelt
Industrial
According to page 8, the contract/design called for 35PSF while Western Wood Products only designed for a '32.16' PSF load. I'm not sure it specifics anywhere what the practical cable strength is/was, that I can see anyway. Edit: I kind of doubt a beefier cable would have saved this design regardless...
![[pipe]](/data/assets/smilies/pipe.gif "[pipe] [pipe]")
Ditto but might just be my cynicism. Report attached below.
So the lower arch cable attachment is suspect. The cable attachment bracket was attached asymmetrically with one bolt in the center of the lower arch. What?!?! The cable itself became frayed but stayed together while the welded bracket failed (not much weld visible either). There is no information regarding wind events that this structure experienced during its brief two month lifespan though a dump of local significant events for 15 years prior is provided. Did this cable fray solely in this event or was the damage initiated in prior events?
Edit: Was the bracket attached/welded only on one side ???? Answer: Not likely
Edit 2: I see now how the second bolt hole was utilized. The north side of the timber bracket is bent underneath the debris and would have been provisioned with a second attachment point. My comment on the welding is still in play. It seems like there is ample linear space for a robust weld connection so it brings into question the quality of the weld. Also with regard to the bolt connection, why the slots and did the bolts work themselves loose?
Photograph 14
Photograph 19
Photograph 20
So the lower arch cable attachment is suspect. The cable attachment bracket was attached asymmetrically with one bolt in the center of the lower arch. What?!?! The cable itself became frayed but stayed together while the welded bracket failed (not much weld visible either). There is no information regarding wind events that this structure experienced during its brief two month lifespan though a dump of local significant events for 15 years prior is provided. Did this cable fray solely in this event or was the damage initiated in prior events?
Edit: Was the bracket attached/welded only on one side ???? Answer: Not likely
Edit 2: I see now how the second bolt hole was utilized. The north side of the timber bracket is bent underneath the debris and would have been provisioned with a second attachment point. My comment on the welding is still in play. It seems like there is ample linear space for a robust weld connection so it brings into question the quality of the weld. Also with regard to the bolt connection, why the slots and did the bolts work themselves loose?
Photograph 14
Photograph 19
Photograph 20
Electronbelt
Industrial
Obviously it shouldn't matter, but keep in mind this particular report was specifically initiated to hold harmless the Neill Grading and Construction Company. I believe there is at least one if not two other groups doing an investigation as well for the other parties involved.
Regarding the welds, I'm kinda surprised the confidence level is high enough to claim they failed while in the air vs the damage in question being the result of the twist and then impact. The area(s) in question clearly had a rough landing.
Regarding the welds, I'm kinda surprised the confidence level is high enough to claim they failed while in the air vs the damage in question being the result of the twist and then impact. The area(s) in question clearly had a rough landing.
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