Another old wood deck collapse, in Malibu 2

[hokie66]

Looks like there is one of these a week now.

https://www.sacbee.com/news/california/article251272799.html

 

[LittleInch]

Again very poor connection detail by the look of it between the 45 degree brace and the end plate. PLus the inevitable nailing of the joists by a couple of nails through the end board.

Actually looking again I think the deck was a small cantilever as it extends further than the ones next door and the real culprit is the join between the brace and the front supporting beam. Or maybe just was never designed, certainly not for 15+ people all clustered at one end.

And a marine environment.

The owner renting (Air BnB?) to some "young people" and guess waht - they decided to invite all their friends to his lovely beach front apartment and they all stood on the deck!

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

 

[drawoh]

Investigators believe the integrity of the balcony and the weight of the group caused the balcony to fall, KABC reported.

So at least we have ruled out space aliens.

--
JHG

 

[itsmoked]

Karma is a bitch..

Keith Cress
kcress -

http://www.flaminsystems.com

 

[JoelTXCive]

 

[phamENG]

Joel - I suspect that is one of the things ASCE tries to address indirectly with the recommended live load 1.5x area served. I still haven't figured out why IBC drops it back down to same as area served.

 

[hokie66]

'Overloaded' is often used by the press and public to describe the reason why these things collapse. But poorly constructed and/or maintained are invariably the culprits.

 

[FacEngrPE]

Live load for a group of people standing, and the same people dancing is significant. Dancing is not a required design consideration for a residence.

https://www.eng-tips.com/viewthread.cfm?qid=209409

https://www.dlsweb.rmit.edu.au/Tool...1_loads_loading/01_primary_loads/page_003.htm

 

[oldrunner]

Many of these decks have rotted wood. Both the Berkeley deck collapse and the Folsom apartment stairway had rotted wood caused by water leaks. The original structural designs appeared adequate. So basically it is an envelope failure which is usually done by an architect.

 

[dik]

I don't know what the deck load is 40, 60, or 100, depending on the jurisdiction... other than vibration, the upper end of the loading is not achievable unless the people are really intimate... nearly all of the deck failures I've looked at have been rot conditions and none have been overload (except as a joint failure).

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

-Dik

 

[phamENG]

FacEngrPE - for lateral loads on decks, this bit of research published in Structure has become my go to. It correlates nicely with other lateral live load requirements for bleachers, etc., so there some confirmation to it. It doesn't typically need to be considered for interior spaces because the lateral design loads from wind and/or seismic tend to be much higher and provide more than enough lateral resistance and stability.

dik - in most of the US it's 40psf for residential (though the recommendation of ASCE is 45psf for a private bedroom balcony in a house or 60psf for a balcony in a multifamily or off of a living room in a single family home) and 100psf for commercial applications. This comes from cases like this and the other thread going right now about the failure in Tennessee. When it comes time for a picture, people do get very intimate and you can approach 100psf very quickly. Add a little dynamic loading and the generally poor connection details with 10 years of neglect and it all comes crashing down.

Here's a frequently posted picture to help illustrate the live loads created by people congregating in a small space:

If you compare the distribution of people in the 50psf picture to the shot from the security camera, they look similar and the security camera shot may even be a bit more dense. Single family home, they were probably right at the required design limit and likely exceeded it in local areas of the deck. Being right on the water, decay of either wood or connections was probably somewhat accelerated and impossible to inspect.

 

[dik]

Thanks... in our neighbourhood, we're not normally that friendly. I knew it was possible... I should have edited my comment to include 'likely'.

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

-Dik