Cost driven decisions in Berkley lead to death. 2

[Prototyper]

The city should immediately revise their standards to allow only metal balconies. They are predictable, weather tolerant, easy to analyze, construct-usually in a shop, install quickly and inspect.

Prayers to the loved ones and their losses.

W L Craig, ME

 

[manstrom]

Because metal doesn't rust.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[sponton]

@MANSTROM haha

I do think that regardless of how harsh codes become when it comes to construction materials and methods, somebody will always find a way to screw around it, basicallly what's happening now.

 

[canwesteng]

I can´t imagine a situation where steel would have failed so soon after construction in a residential environment. Steel rusts but with proper coating it is reasonable to assume it would have lasted the life of the structure in this case, versus what was observed to happen with wood.

 

[manstrom]

Based on the information in the other thread, the balcony appeared to fail because of water infiltration. The waterproofing detail didn't make sense, there was nowhere for water to go, but there was a path in. Once it got in, the wood rotted since it wasn't PT (should have been, but didn't need to be). The design if the balcony was such that the degradation could not be seen since it was enclosed. Additionally, the fact that the balcony was a pure cantilever did not add any redundancy or promote gradual failure. Honestly, I'm surprised that the entire thing failed at once since there were 8 members that had to fail.

If this was a concrete balcony that was not designed for water intrusion, the rebar would have rusted eventually. If it were a steel balcony covered with the same detail, it would have rusted and no one would have noticed. Also, these would cost several times what the wood balcony cost.

The fact that is was wood had nothing to do with it. There are tens of thousands of wood balconies out there. Steel would add cost and complexity. Not to mention thermal bridging issues. For a small fee, these could have been PT and maybe 6 people would still be alive. More over, if the waterproofing detail was better, maybe the water would never have gotten in.

Most decisions in engineering are cost driven. I'm sure carbon fiber titanium balconies would be better than these, but some things are not practical.




When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[canwesteng]

I don't think it's reasonable to use steel in all balconies - wood can be just as safe. But it's ridiculous to say that the steel or rebar would have just rusted away and failed anyway. Steel and concrete are exposed to much more corrosive environments than this and have much longer service life.

 

[manstrom]

Agreed, steel would have been a reasonable alternate. The issues was with waterproofing, not the structural material.

My point is that wood is not an overly cheap, unsafe option.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[SteelPE]

Steel as an option? Then the connection of the steel balcony to the wood structure becomes an issue and real pain to get right... not to mention it probably would have been overlooked as the EOR would have pawned that off to the fabricator to design.

 

[XR250]

yup, then the balcony would have fallen to the ground intact.

 

[LittleInch]

Anything can fail over time. To me the biggest issue is that, presumably for aesthetic purposes, they enclosed the entire thing in stud and stucco and added a concrete floor 2 1/2 " thick on top of the thing.

Having the underside clear could have let water out or allowed inspection / casual looking to see that the wood was not in a good condition. The fact the balcony was probably only used occasionally and then suddenly at the limit of its capacity contributed to the incident, but not being able to see that the beams were in a poor condition was key. I would like to bet that on initial view, most casual observers would have thought the balcony's were made of concrete and didn't dream it was wood inside.

As for not using PT wood, I have no idea how anyone could actually do that to a structure designed to sit outside in all weathers.


The balconey underneath that has been removed was in much better condition. wood isn't the key issue here.

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

 

[msquared48]

To me, this was an envelope issue, a PT issue, as well as a venting issue.

I doubt that the deck was adequately vented, if at all, so that any moisture seeping in from a failed seal or internal condensation could not escape. The rest, unfortunately for some, is history.

Mike McCann, PE, SE (WA)

 

[msquared48]

And I feel that the issue was not so much the cost, as what the Architect did not want to see - external columns supporting the deck. PT wood columns are cheap - at least when compared to the cost of litigation. It could have been done differently and correctly to avoid the problem too.

Mike McCann, PE, SE (WA)

 

[rb1957]

nah, we should outlaw balconies

another day in paradise, or is paradise one day closer ?

 

[msquared48]

But never outlaw cantilevers.

Mike McCann, PE, SE (WA)

 

[canwesteng]

How do columns help? If the wood rots it's going to fail in any case.

 

[msquared48]

Well, the cantilevered untreated joists go away, deferring to a treated ledger and treated exterior framing. Still needs to be well vented.


Mike McCann, PE, SE (WA)

 

[hokie66]

Add me to the list, I think long, of those who would never use wood as the structure of a cantilevered balcony. Not my house, not anyone else's.

 

[msquared48]

The critical issues are a good design, quality construction, and constant maintenance. If any one fails, so does the deck, as with any structure.

Mike McCann, PE, SE (WA)

 

[hokie66]

Mike,
That would be ideal. But in the real world, I think you can rule out constant maintenance. And quality construction, along with our ability to control it, is becoming increasingly rare. That leaves design to compensate for the lack of the other two, and good design can largely overcome.

 

[msquared48]

Unfortunately true Hokie.

Mike McCann, PE, SE (WA)