Posted on 06/16/2015 4:59:20 PM PDT by BenLurkin
Library Gardens served students as well as summer visitors and long-term Berkeley residents. The property was bought in 2007 by New York-based BlackRock properties, an investment firm with more than $4.7 trillion in assets. It then was leased to Virginia-based Greystar, which manages more than 400,000 residences nationwide.
Rent for one- and two-bedroom apartments ranges from $2,150 a month to $4,000; in online reviews residents expressed a broad range of opinions about the quality of the property’s management.
City Councilmember Jesse Arreguin, who represents the area, said the building was "one of the newer apartment complexes in Berkeley.”
He added: “I trust that the Berkeley Fire Department will be able to find the cause of this tragedy, and that this investigation will make sure such events like this do not happen again.”
The building was erected under 1998 building codes, and the balcony should have withstood up to 60 pounds per square inch, according to the city.
But one expert suggested that water seeping into the horizontal support beams could have caused dry rot, contributing to the collapse.
“It appears to be a classic case of dry rot, meaning water intruded into the building [and] rotted the wood” that supported the balcony, said Gene St. Onge, a civil and structural engineer in Oakland. With more than a dozen people on the balcony, “it gave way. It didn’t have enough residual strength, and it failed.”
St. Onge said photos that he reviewed Tuesday morning, showing the broken wooden beams protruding from the building that once held up the balcony, reveal what clearly looks like signs of dry rot.
A structural failure without any dry rot would have looked different, St. Onge said.
The balcony should have been able to support the weight of 13 or 14 people, he added.
(Excerpt) Read more at latimes.com ...
“60 psf on an 8’x10’ balcony is 60 times 80 - 4,800 pounds, the weight of a small SUV and a bit more.”
True, but let’s say 13 people of 170 pounds average (so, 2000 pounds)*. Now, consider the force of those people jumping, perhaps in time with music. And then there are harmonics (although that probably is not material here). Definitely closer than I’d like.
*these were Europeans (Irish?), and were probably “smaller” than Americans these days.
60 psf sounds low; it’s the equivalent of a 180 lb person in a space 1.5’ x 2’.
That might be a bit high for normal use, but the absolute design limit should be much higher than that.
What are the odds that a government inspector signed it off?
The design was probably OK; it would have held the 13 people no matter what they were doing, if the wood was not rotted.
However, if not properly flashed, rainwater seeps in and the beams start to rot. Eventually, the balcony won’t even hold two or three people.
Engineers in other articles have pointed out the obvious dry rot in the supporting beams. They are dark in color, and clearly shredded.
Apparently there must have been rich parents who paid the rent for students on this high-priced apartment.
Parents more willing to spend money on their children than they were willing to instill common sense about not crowding a gang of their partying peers onto the balcony.
-PJ
That they do. I hope we aren’t becoming like South and Southeast Asia or China where cutting corners and downright corruption as regards standards is common.
The deck should have been supported by pressure treated yellow pine. I’m surprised the codes don’t require it.
Guess this is why I’mn not a structural engineer. ;-)
You and me both.
I’m an aircraft navigation engineer.
That’s even scarier.
lol...;-)
True... what something is designed for and what load it fails at are not the same. I don't know what they call it with wood but if we were talking steel, we would be talking about yield strength and ultimate tensile strength etc. The problem with wood is that there is a wide variation in its strength from one stick to the next and thus the safety margins have to be much higher to account for those inconsistencies. For the life of me, I can't imagine how wood is used for this.... and yes, every time I walk down Bourbon St., I stay in the middle of the road. Being there during Mardi Gras would scare the crap out of me.
Built in 2006 and has dry rot?
uhhh. Probably time to drain the king-size waterbed in the bedroom.
R301.5 Live load.
The minimum uniformly distributed live load shall be as provided in Table R301.5.
TABLE R301.5 MINIMUM UNIFORMLY DISTRIBUTED LIVE LOADS (in pounds per square foot)
| USE | LIVE LOAD |
|---|---|
| Uninhabitable attics without storageb | 10 |
| Uninhabitable attics with limited storageb, g | 20 |
| Habitable attics and attics served with fixed stairs | 30 |
| Balconies (exterior) and deckse | 40 |
| Fire escapes | 40 |
| Guardrails and handrailsd | 200h |
| Guardrail in-fill componentsf | 50h |
| Passenger vehicle garagesa | 50a |
| Rooms other than sleeping room | 40 |
| Sleeping rooms | 30 |
| Stairs | 40c |
I’m not sure why they mention Blackrock in the first sentence.
It may have been an engineering failure or it may have been a building inspector’s failure.
I’m not sure why it would be on the property owner.
.....................................................................
Blackrock - Almost $5 trillion in assets, that’s why. My wife has investments with Blackrock.
Looks like 40 lbs/square foot is the relevant number.
Seems reasonable for “typical” use, but I would think the structure should be capable of holding several times that amount, both to allow for higher-than-normal loading, and for degradation over time.
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