Crazy cantilevered steel deck 1

[DoubleStud]

I found this video on youtube. What do you think of this deck? The guy went to the end of the deck and jumped a little bit, you can clearly see the deck moves up and down. At minute 3:55 he shows the structural detail.

 

[Brian Malone]

Very interesting analysis by all! The deck and house design by Steven Baczek looks bold and it will be interesting to see the finished structure. Mr Baczek seems to be confident and not a blowhard. His "150 pound" comments are certainly made in jest. His talk about the design appears to be rather detailed and he seems to be very engaged in the details way beyond of how the structure looks. Since I am not a structural engineer and have not personal building experience I don't have an understanding of why many have said this design obviously had no engineering oversight. Is it because the structure is fully dependent on the 4 anchors resisting rotation or the potential for bounciness or what? If the load on the four anchors and support members are not exceeding safe limits couldn't this design have engineering sign off by an engineer that has a different level of design factors? I get the comments about putting a hot tub on the deck but not everybody would consider putting a hot tub on the deck; a small table and two chairs works well for many. Should every deck be designed explicitly for a hot tub install?

 

[JAE]

I was mentioning that some type of ethical/professional response was called for not because there was no engineer involved (reportedly) and not because I don't trust architects (my son is one of "them") but solely based on the statements above that the numbers didn't work out for steel design and my own concern over longer term weathering degradation in the concrete/anchor area.

 

[Brian Malone]

I am not a PE so I don't know what potential professional censure could occur, so I am missing why any of you who see a grave failing in the design do not personally contact Mr. Baczek and point out your observation(s). The Citicorp building errors were pointed out to the design team and the outcome was a win/win. I see some passive/aggressive suggestions of sending an anonymous message. If there is an obvious concern why must a message be sent anonymously? I ask this as openly as my username is my name.

 

[Eng16080]

I don't have an understanding of why many have said this design obviously had no engineering oversight. Is it because the structure is fully dependent on the 4 anchors resisting rotation or the potential for bounciness or what?

I didn't run any calculations on the anchor bolts, but others here have, and some of them feel they're inadequate. I think that's the reason for this general sentiment. I wouldn't say the design obviously had no engineering oversight, although I think it's possible.

For me, the concern is more in terms of long term maintenance. I can see the concrete and anchor bolts potentially degrading over time, and if the deck is loaded more than it normally is in say 20 or 30 years and it has degraded, there's the potential for a sudden failure. To be realistic, I assume there will be zero maintenance/inspection of this deck and therefore, I wouldn't want to design something exactly like this. I would want some additional redundancy built into the system somehow. I should also add that I'm somewhat low on the risk tolerance spectrum, especially where concrete is involved.

I get the comments about putting a hot tub on the deck but not everybody would consider putting a hot tub on the deck; a small table and two chairs works well for many. Should every deck be designed explicitly for a hot tub install?

Code doesn't require that decks be designed for hot tubs. Depending on which code you're required to follow, the deck live load is likely either 40 psf (IRC) or 60 psf (ASCE 7) assuming this is a residence. Generally, I design for 60 psf. If it's known up front that a hot tub will be installed, an engineer would obviously design for that. If a homeowner decided to add a hot tub later and didn't engage an engineer, there's a good chance the deck would be overloaded and in the worst case could risk collapse.

While a small table, two chairs, and two people is probably the most loading a deck like this will feel on a normal basis, it's nowhere near what code requires. With the 40 psf live load, assuming this deck is something like 8 ft x 16 ft, this would amount to (26) 200 lb people standing on it. Or with the 60 psf loading, it would be (38) 200 lb people!

 

[GeorgeTheCivilEngineer]

I get the comments about putting a hot tub on the deck but not everybody would consider putting a hot tub on the deck; a small table and two chairs works well for many. Should every deck be designed explicitly for a hot tub install?

It's a reference to a meme where hot tubs have been put on some very questionable locations.

 

[ghostdigital]

State of maintenance will matter years from now..

 

[LittleInch]

This video was posted over two years ago so not sure what purpose any notification would pose.

Agree it looks a bit high risk for everything to hang off four bolts, but the highest risk was probably at the first big party which is now long gone....

 

[JAE]

Agree it looks a bit high risk for everything to hang off four bolts, but the highest risk was probably at the first big party which is now long gone....

Well to me the highest risk is the next big party after the concrete around those "iffy" J bolts gets cracked and deteriorated by freeze-thaw action in Columbia, Missouri.