# Balcony Collapse



## Tom738 (Jun 1, 2010)

In the realm of "things that should not be possible in a 2006 building."

http://www.latimes.com/local/lanow/la-me-berkeley-balcony-collapse-20150616-story.html

See also http://www.eng-tips.com/viewthread.cfm?qid=128076 (brief discussion on live loads for balconies and decks)


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## ktkelly (Apr 7, 2007)

When you look at the pictures, it doesn't seem like the balcony was installed very well.

I guess when built no one figured there would that many people on it, so they could save some money by scrimping on the installation.

It's really sad that these young people lost their lives.


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## Oso954 (Jun 23, 2012)

I wouldn't say it was not installed very well at this point in time. So far it looks like water intrusion and rot. 
Whether that is because of the original install, poor maintenance, or some post installation modification remains to be determined.

To accuse the builder of scrimping on the install is premature.


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## Tom738 (Jun 1, 2010)

Oso954 said:


> I wouldn't say it was not installed very well at this point in time. So far it looks like water intrusion and rot.
> Whether that is because of the original install, poor maintenance, or some post installation modification remains to be determined.
> 
> To accuse the builder of scrimping on the install is premature.


The question is going to be what (and who) caused the water intrusion. It's kind of amazing that you can have seven joists snap under the weight of 13 people like that.

http://www.latimes.com/local/lanow/la-me-ln-dry-rot-berkeley-balcony-collapse-20150616-story.html


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## mgp roofing (Aug 15, 2011)

Definitely water ingress issues, possibly around the door threshold and/or handrail fixings. Possibly substandard waterproof membrane product/install also. Just last week, I was putting a new roof on one such house that was having the entire exterior redone after just 13 years, balcony joists & plywood were both rotted to hell. And while I was there, a rep turned up to measure for a conservatory to be installed on a large, similarly built second floor balcony across the street. 2 days later, install contractor turns up followed by the conservatory components, only to discover that balcony has sagged at least 2" in one corner. Cracks were visible in the stucco from across the street; the existing handrail had been fixed through the waterproof surface--I expect that it will have to be completely redone just like the house I was working on--and the one I roofed before it, and the one I am currently on...


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## ktkelly (Apr 7, 2007)

Had this been installed with steel going several feet into the structure, instead of using the wood joists to hold it up....

I am still of the opinion, that while this install was probably done to code, the code that didn't get the job done wasn't nearly enough.


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## Oso954 (Jun 23, 2012)

Steel would not guarantee safety. It would perhaps change the timing of the accident. 

There are a lot of cantilever wood balconies in the Bay Area, some of them dating back as far as the rebuild after the 06 quake/fire. So the question remains about how the waterproofing was missed or failed.

Prior to 9/11, the deadliest structural collapse in US history was the failure of the STEEL supported 2nd and 4th floor walkways at the Hyatt in KC.


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## Oso954 (Jun 23, 2012)

Here is the best pic I have seen of the failed balcony joists.


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## Fix'n it (Mar 12, 2012)

Oso954 said:


> Here is the best pic I have seen of the failed balcony joists.


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## ddawg16 (Aug 15, 2011)

It's the poster child of why we have building codes.

My prayers go out to those families....


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## Tom738 (Jun 1, 2010)

Oso954 said:


> Steel would not guarantee safety. It would perhaps change the timing of the accident.
> 
> There are a lot of cantilever wood balconies in the Bay Area, some of them dating back as far as the rebuild after the 06 quake/fire. So the question remains about how the waterproofing was missed or failed.
> 
> Prior to 9/11, the deadliest structural collapse in US history was the failure of the STEEL supported 2nd and 4th floor walkways at the Hyatt in KC.


True, but not because of water infiltration--IIRC they had connected one balcony to the next and then that second balcony to the third, etc... for support rather than using one support rod that went through all of the balconies. As a result the nut on the first rod was holding up the weight for *multiple* balconies rather than just one balcony, so it didn't hold up under the larger load.


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## Oso954 (Jun 23, 2012)

I did not intend to imply that the KC failure was water intrusion, just that steel is not invulnerable to accidents. It is a great material but still has its weaknesses, or can fail if miss used.

It is not a super material that would have prevented the Berkeley accident. It would have just prolonged the period before the accident happened, assuming that the water intrusion went on undetected.


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## Fix'n it (Mar 12, 2012)

Oso954 said:


> Prior to 9/11, the deadliest structural collapse in US history was the failure of the STEEL supported 2nd and 4th floor walkways at the Hyatt in KC.


i remember that. crazy how someone thought that was not going to pull through. and it would have been so easy to prevent.


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## ddawg16 (Aug 15, 2011)

This was after 9/11...but deadlier

The I-35W Mississippi River Bridge (officially known as Bridge 9340) was an eight-lane, steel truss arch bridge that carried Interstate 35W across the Saint Anthony Falls of the Mississippi River in Minneapolis, Minnesota, United States. During the evening rush hour on August 1, 2007, it suddenly collapsed, killing 13 people and injuring 145. The bridge was Minnesota's second busiest,[4][5] carrying 140,000 vehicles daily.[3] The NTSB cited a design flaw as the likely cause of the collapse, noting that too-thin gusset plate ripped along a line of rivets, and asserted that additional weight on the bridge at the time of the collapse contributed to the catastrophic failure.[6]

Immediately after the collapse, help came from mutual aid in the seven county Minneapolis-Saint Paul metropolitan area and emergency response personnel, charities, and volunteers.[7][8][9] Within a few days of the collapse, the Minnesota Department of Transportation (Mn/DOT) planned a replacement bridge, the I-35W Saint Anthony Falls Bridge. Construction was completed rapidly, and it opened on September 18, 2008.[10][11]


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## Oso954 (Jun 23, 2012)

> This was after 9/11...but deadlier


I assume you mean that I35 was deadlier than KC ?

KC was 114 killed and 216 injured, so I am not sure how you got to that conclusion.


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## gregzoll (Dec 25, 2006)

Oso954 the Hyatt bridge accident was caused because the Steelworkers neglected to use nuts and bolts as specified, along with the Engineer did not calculate for a large live load.

During the build of the Rosemont Horizon in Rosemont, iL. The Steelworkers again did not put enough plates on the wood beams. When they started to inspect the wood beams. They found some plates only had 2, maybe 4 bolts. Some had no nuts on the bolts.

https://failures.wikispaces.com/Rosemont+Horizon+Arena

The Hyatt-Regency KC collapse info. https://failures.wikispaces.com/Kansas+City+Hyatt+Regency+Walkways


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## mgp roofing (Aug 15, 2011)

I just looked up the LA Times article posted above; the words "Grace Bituthene" are clearly visible on the waterproof membrane. Having Googled the product install details here https://grace.com/construction/en-us/waterproofing/Bituthene-System-4000 it appears that this product is not intended for waterproofing timber decks . 
And New Zealand building codes require CCA treated exterior grade timbers for all components of such decks/balconies nowadays. And its a great idea as it means the water ingress is likely to be detected before the structure becomes unsafe :thumbsup:


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## Oso954 (Jun 23, 2012)

> Oso954 the Hyatt bridge accident was caused because the Steelworkers neglected to use nuts and bolts as specified, along with the Engineer did not calculate for a large live load.


I can't agree with that statement.

The original design was substandard. It would have not met KC code at the time. However, the prime cause was the design change originated by the steel fabricator. It changed the design to support the 2nd floor walkway from the 4th floor walkway box beams, rather than the original continuous rod. This doubled the load on the already subcode box beam, as well as on the nuts connecting them to the ceiling support rod. (This change is shown in the link you provided)

This design change was approved (stamped and signed) by two engineers at the project engineering firm. Both of the engineers and the firm lost their liscenses as a result.

The Steelworkers erected the walkways per the approved drawings.


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## mgp roofing (Aug 15, 2011)

I don't agree either. A good explanation is here: https://www.youtube.com/watch?v=e72My2DrZbs


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## Daniel Holzman (Mar 10, 2009)

I recall the walkway collapse very well. There is a good discussion about the case here http://www.engineering.com/Library/...cleID/175/Hyatt-Regency-Walkway-Collapse.aspx.

Certainly one thing the Hyatt collapse points out is the complexity of assigning fault and responsibility in modern construction, where there is often a separate designer, fabricator, installer, and inspector, and there is room for miscommunication along the entire chain.

In the world of forensic investigation, it is necessary to reserve judgement, check all the facts, investigate many alternative hypotheses, and accept that in some cases the truth will never be known. On an internet chat forum such as this, where few are licensed, and rarely does anyone have direct knowledge and involvement in a case, it is easy to throw out flippant (and perhaps erroneous) conclusions regarding cause and origin. This thread is a good example, there are a number of individuals who seem to believe they know the reason for the collapse, with no direct involvement in the case, no opportunity to examine the site except perhaps a few photos or a video, and possibly no professional qualifications to offer opinions. But that is the nature of an internet chat forum, everyone is entitled to an opinion, and it is difficult to distinguish truth from fiction.


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## Oso954 (Jun 23, 2012)

Back to the Berkeley balcony subject, their was a memorial service yesterday for the local girl and her cousin that were killed in the fall.
I am posting the link to the newspaper article just in case someone is interested.
http://www.pressdemocrat.com/news/4091999-181/friends-family-mourn-rohnert-park


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## Oso954 (Jun 23, 2012)

Here is the Berkeley City Staff Report on the balcony collapse with recommended code changes for the future.
http://cityofberkeley.info/uploadedFiles/City_Manager/Press_Releases/2015/Staff%20Recommendation.pdf


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## gregzoll (Dec 25, 2006)

Pretty quick for the city to cover up the real reason why it happened, along with making "changes", so that it does not happen again, which is an understatement.

All Berkely did, was remove any doubt of liability on their side, for a building inspector not doing their job to inspect it from the beginning.


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## mgp roofing (Aug 15, 2011)

Suffice to say, the construction methods used originally, and the code amendments indicated in the report, still would not be sufficient here in New Zealand. All of the timber components including joists, blocking and the substrate for the waterproof membrane, would have to be minimum CCA treated, and stainless fasteners used, to meet code. And I have never seen a poured concrete deck surface constructed on top of a wood structure. That effectively makes inspection of the waterproof membrane all but impossible. And, as I have said earlier, the bituthene membrane is not intended for this application--a roofing membrane such as mod-bit or TPO should have been used with a removable surface of wood or loose-laid pavers on suitable supports to protect the membrane from damage.


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## ammumalar (Jun 23, 2015)

actually it is very complicated to choose area for this
still i don't have correct idea about this balcony


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## briana26 (Sep 11, 2015)

Oh. That's really sad.


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