According to experts, dry rot is the likely reason for the collapse of a fourth-floor balcony in Berkeley that killed six Irish students. Three separate investigations are currently underway to determine the reason for the collapse in this relatively new US apartment complex.
According to Darrick Hom, president of the Structural Engineers Assn. of Northern California and an Oakland structural engineer for Estructure, the wood of the balcony support was in fact so deteriorated that it broke off at the touch of workers at the scene. “It was decayed. They were touching it with their hand and pieces were coming off,” he said. “Obviously, if you touch a wood beam on your deck, it should not come off in your hand,”
Gene St. Onge, a civil and structural engineer in Oakland, believes that water seeping into the horizontal beams supporting the balcony may have caused dry rot which weakened the balcony’s ability to support itself and the people standing on it.
“It appears to be a classic case of dry rot, meaning water intruded into the building [and] rotted the wood,” he told the LA Times.
At the time of the collapse, it is believed that 13 people were standing on the balcony. With this many standing on the weakened support structure, “it gave way. It didn’t have enough residual strength, and it failed.”
Looking at the remains of the balcony on the building’s fourth floor, he continued, “It appeared to be shredded and darkened and had all the appearance of wood that had been totally compromised by dry rot.”
If it wasn’t for dry rot, he states, the balcony should have been able to support the number of people standing on it.
“If you had 14 people, and they were all -- I don’t know -- football players, and they were jumping up and down, you would get a fair amount of deflection, depending on how well the railing was tied back. But if the [wooden supports] were designed even under minimal standards, it should still have held.”
Hom’s inspection of the balcony coincided with St Onge’s. “Just the pure weight is not the deciding factor,” he commented.
After the inspection of the balcony on the third floor, workers concluded that the balcony had been built to minimum code and should have been able to support 13 people.
Bernard Cuzzillo, a consulting engineer who has a doctorate in mechanical engineering at UC Berkeley, agrees that the balcony showed signs of rot. Although not part of the official investigation, he visited the balcony scene on Tuesday and told the LA Times that there was visible mould in one of the broken wooden joists. He said that the wooden joist broke into short fibers at the failure point where as, if the wood had not rotted, “you would see long slender splinters. It would look like a broken baseball bat.”
“That junction, where the [wooden] members come up beyond the exterior wall, is critically important to waterproof properly,” explains St. Onge.
“It appears as though that something failed there. Either the detailing wasn’t adequate, or the construction was not done properly, or something happened that allowed water to intrude.
“We’re seeing a lot of structures going back to the ’60s and ’70s -- they were built properly at the time – they’re starting to fail or failing completely because of age, and they’ve been neglected and not taken care of,” he continues.
“There have been a number of cases where decks have failed just simply because the owners haven’t been paying attention and repairing or replacing them as they should.”
“To see something like this is very unexpected,” commented Hom. “It will be important to learn from this and prevent this from happening in the future.”
Mayor of the City of Berkeley, Tom Bates also wishes to prevent this from happening again, calling the tragedy a “wake-up call” and announcing that city officials will now inspect 13 other buildings under construction in the city to ensure they are safe.
The balcony and apartment are located in the Library Garden complex at 2020 Kittredge Street and was just completed in 2007. The building has 175 rental units consisting of one- to two- bedroom apartments that can be rented for between $2,150 a month to $4,000. The owner of the land is listed as Granite Library Gardens, an investment fund managed by New York-based BlackRock.
Blackrock released a statement saying, “we are terribly saddened by the tragic accident at Library Gardens and our hearts go out to the victims and their families. The loss of young life is truly heartbreaking and our sincerest condolences go out to all the families and communities affected by today’s terrible accident.”
They also stated that they were in “close contact with the building’s management company and an independent structural engineer is being dispatched to conduct a thorough review of the situation.”
City officials are so far declining to comment as the investigation into the accident continues.
"In 48 hours we should know more," said Matthai Chakko, a city spokesman.
In the early hours of Tuesday morning, emergency services were alerted to the tragic balcony collapse in which six died and seven more were injured. The six victims have since been named as Irish students Olivia Burke, 21; Eoghan Culligan, 21; Lorcan Miller, 21; Niccolai Schuster, 21; Eimear Walsh, 21; and Ashley Donohue, aged 22.
Ashley Donohue, a cousin of fellow victim Olivia Burke, is Irish-American and currently resides in Santa Rosa in the Bay Area.
Families of the deceased and injured are currently traveling to Berkeley.