Another deck collapse, this time in Tennessee

[hokie66]

https://edition.cnn.com/2021/05/02/us/tennessee-restaurant-deck-collapse/index.html

 

[JohnRBaker]

Could this have been the result of 'outdoor' spaces being used for guests which wasn't originally designed to hold so much live load? What I mean is, many restaurants are looking for outdoor dining and party spaces in buildings which were never designed with that in mind.

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[dik]

If you have a fully loaded parkade with vehicles parked side by side and end to end... you may have 20 psf live load. I'm not sure that design load is an issue. Judging from the size of those members it does not appear underdesigned... possibly a systemic connection failure would be my first 'kick at the cat', or a poor construction detail.

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-Dik

 

[IRstuff]

It looks like there might have been a midspan column that collapsed

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[hokie66]

Maybe prejudging from limited photographic evidence, but these things are almost always either from wood rot or inadequate connections. My bet on this one is connections. Probably no real engineering involved, just slapped up by good ol' boy self described carpenters.

 

[LittleInch]

Those cross beans look like they were nailed into the end plate. Terrible design and whatever was holding up the deck in the wall side isn't there anymore

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[dik]

What permit? You often see photos of collapse, but it's not often that someone gets up close and takes photos of the connections, etc.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Tomfh]

Those cross beans look like they were nailed into the end plate

It must be so widespread a method. I've owned two houses, both which used the method. One I retrofitted bolted brackets to, and one which I left as it wasn't critical. There must be millions around the world done that way, including many that will fail at relatively small loads.

 

[LittleInch]

Not only that but the front plate rests on a little cut out held on by two nails....

I do like the fact that after a deck collapse there is then a large gathering on the adjacent deck!!

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[azcats]

I think the stairs where the people are gathered are independent of the deck.

Few more photos here:

https://twitter.com/HamCoTNES/status/1388632890892816390

 

[LittleInch]

azczts - maybe, but it was probably built by the same firm....

This has more details and pictures.

https://newschannel9.com/news/local/deck-with-40-people-on-it-collapses-at-soddy-daisy-restaurant

The rest of the deck looks pretty ropey as well.

Apparently a "group" gathered on the deck for pictures over looking the lake when it collapsed in the centre, so that rather weedy looking post may well have given up the unequal struggle or the end plates just came off it.



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[azcats]

You might be right LittleInch - I saw the stone covered sides of the stairway and got the impression it was an entirely different entity.

 

[azcats]

Top side view.

 

[LittleInch]

It clearly wasn't really being looked after, but going to a restaurant you expect that what you're sitting on won't collapse.

Looking at this photo it looks to me like the front plate attachment to the post was a small cut out into the post of maybe only 1" or 2" at most over a length of 2", held there by two nails or screws. So if say 15 people gathered next to the post then you're looking at upwards of 750 kg on each connection. Terrible design.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IRstuff]

There are also the diagonal struts as well as the column that broke, which also had diagonal struts.

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[azcats]

My guess is that the post/diagonals/'beam' all just fell over and away after the joist/beam connection failed. Looks like there were 3 nails into the end grain of each joist.

If the photo below comes thru w/ any resolution you can zoom in and see the nails bent over.

 

[NOLAscience]

"40 people had fallen" and "They all congregated outside on the deck to take a group photo". Two bits says they were all grouped up, right at the handrail so that they'd get the beautiful lake in the background. Local overload, but also inadequate connections (toe-nails).