Design of balcony in fatal Berkeley collapse was sound, outside expert says

[Molly Brown]

[trader_4]

I was wondering about code for high balconies like that. I've seen wood joists used for balconies here that are two stories up, but they are also exposed underneath so that you can see if they are rotting. I'd really be worried about a balcony, especially one that is 4 stories up, where it's supported by wood joists and enclosed so you can't see the condition. Also, enclosed like that one was, if water gets in, it's perfect for rotting it out.

Also, wasn't there like 13 people on it? That's a small balcony to have so many people. It's supposed to hold them.... I wonder if there was any indication that something was wrong, like it having some movement, before it gave way? I've been on plenty of hotel balconies up high, but AFAIK, they were steel/concrete construction.

[Scott Lurndal]

The balcony design live load (which it met) was 60 pounds per square foot. _If_[*] the balcony were 8x4 (32 square feet), that would then support a one-ton (1920 pounds) load.

13 people at an average weight of 154 pounds each (irish) or 180[**] pounds each (american) works out to 2002 to 2340 pounds. [*] Haven't seen the actual dimensions reported yet, yet the design load of 60psf is only allowed if the balcony is less than 100sq/ft, else the design load would be 100psf. [**]

[Mayayana]

|

The *design* is claimed to be sound. That's an odd thing to say. It's based on looking at design plans rather than looking at the deck! I'm guessing the engineer is trying not to ruffle feathers. The photo seems to clearly show dark gray wood that should be almost white if it weren't rotted from long exposure to water. The joists look punky from long water exposure. There also seems to be fungus and mildew on the bottom of the subfloor.

[dpb]

Well, the engineer's report says it wasn't overloaded per the initial design...of course, clearly from the picture there wasn't but a few inches of solid timber left so as it was, it was _way_ overloaded.

And, the story goes on to say that it passed all pertinent inspections during construction. Code doesn't specify the construction materials, only strength and such of the finished structure. It's up to the engineer/architect to meet those and provide the details of installation that meet the "workmanlike" standard of construction that covers all the details of things like the flashing, etc., etc., etc., that aren't actually given by Code per se.

As the story says, where the breakdown was is yet to be fully determined but it looks like the preliminary conclusion is it wasn't design or details. Hence it would almost have to be in installation/construction or later modifications, perhaps that breached the initial flashing details. As you note, that they were enclosed so couldn't see the deterioration and that prevents drying once there is water intrusion was a bad idea...doesn't indicate whether that was initial design or a retrofit altho would presume was probably original.

This'll be a "two-lawyer deal" before this settles out, for sure as a local old-timer is wont to say...

[trader_4]

Doesn't seem at all odd to me. It's probably because the LA Times found some engineer and all he has to go on is the plans. He can't just show up and say "I'm here to see the failed deck....." or if he does, little likelihood he's going to be allowed to do so.

[Ed Pawlowski]

The engineer said the design was OK, but obviously, it was not. They did not properly waterproof it or make provision for easy inspection. If they did, it may have been OK.

Also possible it was designed to be open and the builder enclosed it and did a poor job. In any case, if other building were built like that they should be inspected too.

[taxed and spent]

The DESIGN is on paper. Looking at the deck will not tell you about the DESIGN, it will tell you how it was actually built, and how it has deteriorated.

[Mayayana]

| As the story says, where the breakdown was is yet to be fully determined | but it looks like the preliminary conclusion is it wasn't design or | details. Hence it would almost have to be in installation/construction | or later modifications, perhaps that breached the initial flashing | details.

Maybe not. There are plenty of construction details that are perfectly legal but not a good idea. If the seal depends on gluing or caulking rather than natural shedding of water that's never a good idea. Balconies that are part in, part out are common in "modern" buildings. For instance, I have customers who have "inset" decks off their living rooms, with flat rubber rooves, on top of garages. It's really interior construction but with a rubber roof to seal the floor. If the rubber is breached, or the glue fails, the joists rot. But the garage has a plaster ceiling. Like these balconies, it can get very bad before it's noticeable. But it's all legal.

A great example of this kind of problem is the MIT stata Center.

MIT apparently wanted the glamour and gossip that would go with hiring post-modern rockstar Frank Geary to blurt out some of his whimsicality-as-art on their computer science building facade. I saw the building close up. In addition to being just plain silly, and completely unrelated to the function of the building itself, there seemed to be numerous joints around windows and where walls met that depended only on caulking. (Note the flat-top dormer style windows.)

As with so many architects who want to think of themselves as great artists, the pictures of the Stata Center show a total disregard for common sense and an apparent lack of familiarity with the actual materials used. (Those tedious details are for the visionless lackies to worry about.) I think of it as "artist neurosis". Like the painter who paints a dot on a giant canvas, or like John Cage writing a musical piece with no sound, art itself is neglected as the artist tries to prove themselves to be an artist, which they do through a perverse attack on expectations: "I'm a real artist, so if I call this dot art then it is art, which proves I'm a real artist! So there!"

Geary is a famous darling of the architecture world and probably had plenty of engineer's stamps to satisfy building inspectors. (They never want to be on the hook for any design that's the least bit unusual.)

Another great example is the ceiling panels in the Boston Expressway tunnels. One night one of them fell on a car and killed people. It was a panel more than

2 lanes wide and many yards long, made of concrete. Many, many tons of weight. They were glued into the ceiling above! I have no idea how anyone with any common sense could design or put up such a structure without setting it on ground-based support. Yet the experts argued about whether the glue was applied properly, not about the obvious problem of hanging a concrete panel the size of a many-storey building wall from a ceiling, with glue!

[Ed Pawlowski]

The design may have been structurally sound and adequate if it was not rotted. The blame goes to either improper design for waterproofing or the installation of it.

[dpb]

Now maybe this guy is incompetent but it appears that from his evaluation the fault wasn't with design/detailing...

[Mayayana]

| Now maybe this guy is incompetent but it appears that from his | evaluation the fault wasn't with design/detailing... |

Yes. I read it the same way. But even if the design was properly implemented, my point was that lots of designs are faulty, whether or not they're legal or officially approved. That was what I was getting at with my examples of the Geary building, the condo decks, and the Boston tunnel ceilings I described.

The expert they consulted was merely saying that the design is officially acceptable. That says nothing about whether that design was implemented, nor does it necessarily mean the design was truly serviceable. It's really just a preliminary finding that means very little other than to say the parade of officiality has begun to address the event.

[dpb]

So why did you post it after my comment seemingly disagreeing? That's a different subject/possibility; make that as a standalone point if desired.

Now I don't know which "expert" you're referring to; the one in the article quoted said in his opinion it _was_ designed well.

[trader_4]

More to the point, if the engineer thought that design was in anyway inadequate, fault prone, not a good way of doing it, he could have said that. He didn't. He said that if it was built to the design and properly maintained that it would not have happened.

I didn't see him confining his remarks to just officially acceptable. And if it was inherently unserviceable, a bad idea, he sure had an opportunity to say that. This also has nothing to do with the official parade, the engineer in the article is unconnected to the investigation.

But that said, it still seems like a bad idea to rely on wood support for balconies where the wood is enclosed and not open for inspection. The thing was only 4 years old, water must have gotten in there from the beginning. But how you could count on that kind of design for 20, 30, 50 years, IDK.

[Mayayana]

"but it looks like the preliminary conclusion is it wasn't design or details. Hence it would almost have to be in installation/construction or later modifications"

I disagreed with your conclusion. I think it's an important point. The construction *could* be faulty, but it was not necessarily a problem with the construction or later modifications. A design can be legal and officially approved while still being bad and prone to failure. I gave 3 examples. The pictures of this apt building lead me to think that the balcony collapse may very well be a similar case.

[trader_4]

How can construction be both faulty and not necessarily a problem?

Again, the independent engineer that just reviewed it and knowing what happened, would be pretty dumb to say that he doesn't see anything wrong with the design if he thought it was actually bad and prone to failure.

[micky]

He could rappel down from the roof.

[micky]

The news quoted someone, supposed to be formerly on the board of directors of the building, who said they were only supposed to be decorative. I bet they never told anyone that.

Still, don't be the last person to fill up a balcony, or the two before that.

[philo]

From the photo it sure looks like it was rotted

[trader_4]

Whoever said that is full of baloney. You'd never be allowed to have balconies that are accessible that don't meet the building code for real balconies. Also, the engineer who reviewed the plans for the LA Times in this thread surely would have commented on that, if there were any truth to it.