Berkeley Balcony Collapse

Archive of Older Topics Archive Coffee Pot and Water Cooler #2
1

Any architects/spec writers in Berkeley able to advise on this tragedy near the USC campus, I understand 5 have died initially and photos of the scene are unclear whether this was a wood or concrete balcony that was apparently overloaded. Ironically there was a woman who fell to her death from a balcony in NYC today.

BALCONIES are back in the news. Its ironic too because I am having a heated conversation with a GC and Developer regarding balcony construction on a SFL project. Their claim being that the architect and specwriter have over specified the balcony components, specifically the use of galvanized steel in the concrete deck.

2

Definitely wood construction based on pictures
http://www.latimes.com/local/lanow/la-me-berkeley-balcony-collapse-20150616-story.html

3

I never cease to be amazed by owners who want to tell us how to do our jobs, but then want us to be responsible and liable for their decisions.

4

I never cease to be amazed by owners who want to tell us how to do our jobs, but then want us to be responsible and liable for their decisions.

5

Without comment on the collapse but USC refers to University of Southern California. UC Berkeley is located in Northern California.

6

My apologies, only been to Calif once, visited Fresno and Big Sur.

Looking at some of the news feeds, that building elevation has consistent repeat faade elements, except for those two oddball balconies, very curious design? Almost looks like those balconies were tacked on after.

7

Mark,

We should excuse Jerome as he is south Florida and may not be familiar with CA geography.

From the picture I saw this morning, it looked like wood construction, but it wasn’t possible to see the condition of the wood.

8

From the San Francisco Chronicle:
http://www.sfgate.com/bayarea/article/Five-dead-8-hurt-in-Berkeley-balcony-collapse-6329902.php#photo-8158978

It looks like cantilever wood beams snapped off right at the wall line.

The balcony below seems to have been completely filled in with security grills, perhaps for children, making it hard to interpret the images.

9

Steve, that’s as good a photo of the condition as I’ve seen. I agree that it appears that cantilevered beams appear to have sheared off. What’s odd to me is that there is no bright white, freshly exposed wood evident. Not even shards or splinters. The amount of dark wood material at the failure points suggests to me that those beams were rotted out, perhaps severely. Conjecture only, but given the photo…

10

No, I am changing my mind. Cantilever beams on a deck condition are not the norm for multifamily construction. There appears to be a ledger beam, and the deck joists are attached to it. I can’t see joist hangers, but they are common.

What’s also odd is that you can clearly see deck joists and slatted wood decking. It appears to be the underside of the deck that is visible, but that is hard to explain given the railings. I don’t know. Something is really weird about that photo.

11

I agree. at first it seems to have swung down almost as if it was hinged at the wall line and then dropped a couple feet to land on the guardrail of the balcony below it. But if that was the case we would be looking at the walking surface, but as you note, it seems like we are looking at the underside of the balcony.

12

Nathan, if you are correct and that is a ledger than the decks could have been added after CO, not being part of the design. I did not see the actual balcony floor in any of the pics. I hope you guys keep this post alive, I am curious as to what conclusions are reached. Also how is the wood rotten when you’ve had 4 years of drought? My guess is that those decks were never permitted and thus not designed or built correctly.

13

Given that those are french doors leading to the Deck, they are most likely part of the original design. Just because there are only a few decks does not necessarily point to a retrofit. Multi-family designers often use various components across an elevation to break up the monotony of an elevation, and julliette balconies are one such method of doing so.

As for drought, its kind of irrelevant. It still does rain, and people still hose off their decks, and there is still condensation, poor ventilation, and atmospheric fog/dew point conditions, particularly in San Francisco. There’s plenty of moisture vapor in the air to rot out a few wood joists

14

Based on the reports 5 killed and 7 injured means that there were at least 12 people on what appears to be a rather small balcony. Could overloading be a major contributing factor?

15

Latest report indicates it’s now 6 dead & 7 injured - total of 13

Weight could be a contributing factor.

We probably won’t know the whole story until the report comes out.

16

Richard,

Don’t assume all the casualties were ON the balcony. Some could have been under it or at street level.

Let’s all learn from this and other building failures so we can better serve and protect the public.

17

Even if the loads were in excess of what is required by code I would not expect that to be the primary cause of the failure.

Local speculation here in Berkeley, is that it is the result of decay.

Cantilevered wood joist are not that uncommon for this type of construction.

18

San Francisco and the Bay Area have an unfortunate history of raised decks collapsing with multiple injuries if not fatalities.

Usually though, the culprit is a decades old carpenter-built deck built with rule-of-thumb engineering off the back of a Victorian. Add too many party guests, moving to the simple beat of techno/house/etc and you are simulating a Richter Scale 8 earthquake.

19

Here’s what I gather from the images (and news articles text):

The deck failed and the railing pivoted downward at the floor line, 180 degrees, so that it rested immediately above and directly in line with/over the railing on the balcony below.

Cantilevered wood members failed, appear wet and rotted.

Waterproofing membrane is a single layer of self-adhering SBS modified asphalt - Grace Bituthene is clearly legible on the portion that remains hanging over the sheared wood members. This waterproofing appears to have been applied over composite wood deck/sheathing material (looks like OSB to me).

Looks like poured concrete walking surface was placed over the waterproofing membrane, flush with the sheet metal flashing at the deck perimeter. Which means that the waterproofing was recessed into the deck construction, which also means that it was likely turned UP at the edges, and since I do not see any drains, that it was allowed to sit in this recess and to evaporate/dry when/if it could after rain events. Due to this condition, there was likely quite a bit of water sitting in the bathtub that was formed by the waterproofing membrane, and likely found multiple routes of entry into the wood structure below.

The railing supports look to be attached to the wood deck/sheathing BELOW the concrete paving, and very likely anchored with wood fasteners THROUGH the waterproofing membrane, which is one route of entry for the water. If not attached through the WP with fasteners, the peel and stick membrane would have needed to be carefully brought up and around each railing upright to create a watertight condition, and I can see no evidence of that in the images.

This is such a tragic thing to have happened. If designed like what I can see/suspect, I think that the architect is going to have a tough time ahead. If the Contractor/Developer changed the design from something the architect had originally designed/documented, then it is that party that will suffer legally. The statute of limitations in CA for latent defects is 10 years from time of “completion.” The architect’s web site states that this project, Library Gardens, was under construction in 2005, so lawsuits will easily make the 10 year time limit.

All of the parties involved in the design and construction of this project should be very, very troubled by this. If I were an owner or renter of any project designed by the architect for this building, I would be worried as well. Ditto that for those in buildings developed and built by same parties that did this building.

20

The failure occurred a foot or more from the face of the wall. Definitely not at the point of maximum bending moment.