Another deck collapse
Another deck collapse
(OP)
https://www.yahoo.com/gma/deck-collapses-montana-l...
TTFN (ta ta for now)
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RE: Another deck collapse
I’m looking at the photo and trying to determine possible failure modes. Here are the observations I see:
1) The joists are running left to right so it’s okay that we don’t see joist hangers on the house ledger board.
2) Why is there a column on the ground? I’m guessing that it was not embedded in the ground. Was it even connected to a footing and was there any lateral restraint? The furthest right column appears ‘kicked out’ at the base, which makes me think the columns are not attached to footings at all.
3) The beams on the furthest right do not appear to be notched into the columns, which makes me think they were mechanically fastened somehow.
Perhaps some sort of shear failure of connectors at the beam column connection led to the collapse? I’m thinking a punching shear type failure at the column?
What do ya’ll think?
RE: Another deck collapse
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Another deck collapse
More pictures would help.
RE: Another deck collapse
Richard Feynman's Problem Solving Algorithm
1. Write down the problem.
2. Think very hard.
3. Write down the answer.
RE: Another deck collapse
RE: Another deck collapse
Keith Cress
kcress - http://www.flaminsystems.com
RE: Another deck collapse
They are not trusses, they are timber beams with joist hangers still in place. The joists have been dislodged, but are still mostly still attached to the decking boards.
I can't figure how the beams were connected to the columns, but obviously quite tenuously.
RE: Another deck collapse
Some discoloration around the connection. Glue?
Can you walk up a little closer before you take the next picture.
Richard Feynman's Problem Solving Algorithm
1. Write down the problem.
2. Think very hard.
3. Write down the answer.
RE: Another deck collapse
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Another deck collapse
You don't happen to have a tape measure do you?
Richard Feynman's Problem Solving Algorithm
1. Write down the problem.
2. Think very hard.
3. Write down the answer.
RE: Another deck collapse
The columns are restrained from moving outward by the roof on the section to the left, but not on the section that failed?
RE: Another deck collapse
RE: Another deck collapse
Just glad to read there were no casualties in the linked story.
RE: Another deck collapse
I'm guessing 99%.
RE: Another deck collapse
RE: Another deck collapse
RE: Another deck collapse
There are three near-square deck sections in the first picture. the primary failure appears to be the right deck square of those three squares. The center and left-hand deck square remain attached at one side, but have also fallen as their beams moved to the viewer's right when the furthest-right deck square failed. All three deck squares remained "near intact" as they fell = The deck boards were sutiably fastened to the deck joists, but the joist-to-beam connections failed.
Now, look at the furthest right deck square in the lower pictures.
The left sides of the left-right under-deck joists are fastened into a series of box-store "standard" deck joist attachments to the deck beams. The right side of those same joists are attached with "nothing visible" (no pulled out nails, no screws, no joist hangers, no tenons, no cut-in notches ...
What is the UBC Code rating for "magic" fasteners?
I suspect the right-most deck square was held by the deck boards being supported by the small board still attached to the deck beam. The load was carried from (unattached) deck joists to rightmost deck board, which was held up by the board still nailed to the beam.
RE: Another deck collapse
A chain of optometrists here has a commercial "Should have gone to Specsavers".
The joist hangers are still on the beam.
RE: Another deck collapse
Joist hangers are clearly visible on both the left and right beams of that deck section in the last picture IRstuff posted.
RE: Another deck collapse
Outside of the connections, is this another Hyatt Regency walkway live loading scenario?
Mike McCann, PE, SE (WA)
RE: Another deck collapse
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm
RE: Another deck collapse
Richard Feynman's Problem Solving Algorithm
1. Write down the problem.
2. Think very hard.
3. Write down the answer.