Building collapses at construction site in north Winnipeg 2

[KootK]

Link

All of the mandatory temporary/permanent truss bracing must have blown off during the collapse...

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

Oh Koot that's so last week's news around here. It had all of the wall sheathing on and all of the trusses up. I didn't get to see if it had any temp bracing in place. For sure the permanent truss bracing was not in place.

Also there are unconfirmed reports that one gable end may have been a massive door essentially turning it into a 3 sided structure.

To be clear, I have no direct knowledge of the design nor the construction. It just happened about a 5 minute drive from my house. Drove by the night before and it was standing. The next day it was flat on the ground.

 

[hokie66]

The article says it was a 2 storey structure. There doesn't look to be enough space under those roof trusses for the amount of timber you would expect for the upper floor and two levels of walls.

 

[VEBill]

Balloon framing, before the 2nd floor had been installed?

 

[waross]

They had been working on the framework for the large, two-storey shop space for six weeks.
Probably not going to be a second floor.

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

 

[hokie66]

I took that to mean two storeys of shops. So you think it was a two storey high workshop?

 

[waross]

I understood it to be a high shop. Possibly for servicing heavy equipment and/or large trucks. But you may be correct also. Can't tell by the pictures. grin

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

 

[jayrod12]

I understand it as that as well. It's enough room for two storeys, i.e. around 18-20 ft tall. But I don't believe there was a second floor.

 

[boo1]

Gable end wall in the fore ground looks like 2x8

 

[KootK]

You can't trust media folks to ever get any of this stuff right I'm afraid.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[JAE]

I was hired once to investigate a collapse very much like that one.

It was a rural hog confinement building that was getting framed up on a concrete foundation.
The framing was comprised of:
1. 2x8 wood studs @ 16" o.c.
2. A double 2x8 wood top plate
3. Premanufactured wood trusses @ 24" o.c.
4. Building was about 80 ft (truss span) by 300 ft + long.


What happened was that they completed the stud framing (no sheathing) and used 2x6 temporary diagonal braces up the sides of the studs with double headed nails into the edges of each stud.
They had the trusses 80% installed with diagonal 2x bracing on the tops of the trusses.

But when they left that night with 20% of the trusses still to go, a windstorm came up and blew the stud framing out of plumb by about 1 inch.
The next morning they found what happened and had all their men stand by the diagonal stud braces down the length of the building.
They brought a front end loader (or bulldozer - can't remember which) to the end of the building and tied two cables with two come-alongs to the top ends of the two long walls.
They then had all the men pull the double headed nails on the bracing - the idea was to then crank the come-alongs slowly to plumb up the studs - then have the men re-nail the braces.

However, as they brought the studs up to plumb they never figured that the tension on the cables would just keep pulling on the wall - the studs came up plumb - but then just kept coming.

All the men saw what was happening and jumped through the studs walls to the ground below as the whole assembly collapsed toward the front end loader.

They filed a claim with their insurance claiming that the wind blew it over.



Check out Eng-Tips Forum's Policies here:
faq731-376

 

[TehMightyEngineer]

Fantastic story JAE, love the ending.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[boo1]

Question:
Are the wind loads higher on the open trusses then the sheathed trusses?

 

[hokie66]

boo1,

No.

 

[dik]

A response from one of my colleagues, "Hello Dik;

Only what you see in the picture. I saw it under construction from the North perimeter. Truss Roof was being put together on the ground to be lifted by a crane in sections.
It looks to me like the walls failed as the back roof section simply lay down intact."