Khalid Mosalam is a professor of structural engineering. He joined ABC7 program “Getting Answers” Monday to discuss the collapse of the building that has now claimed 11 lives.
“It will take a while until we know exactly what happened,” said Professor Mosalam. “But considering that this building was built 40 years ago, one can only speculate that the code provisions that were followed at the time were not as robust as the ones we have these days.”
For a collapse of this magnitude to occur, Mosalam said there had to have been an anomaly in the building, something related to the foundation or the ground.
He said Florida’s marine climate and erosion related to the building along the boardwalk could also have compromised the building’s capacity.
“Fortunately, these failures are very rare,” he said.
However, the rarity does not lessen the consequences, he said.
Now, could this happen in San Francisco, a city full of tall buildings, surrounded by water?
“Here in California we obviously care a lot about earthquakes, so most of our structures are designed with that in mind,” he said.
And with that, he said, comes resilience.
San Francisco’s Millennium Tower is known to be sinking, but Mosalam thinks it’s not much of a concern.
He also mentioned the distinction between a skyscraper and a mid-rise building.
As of February 2020, The 58-story building had sunk 17 inches and tilted two inches since it first opened in 2009.
The UC Berkeley professor emphasized that a plan needs to be implemented due to “external” factors, such as a fire or an earthquake, which can lead to abnormal conditions.
“If we have a building collapse situation, we have to monitor it. There is no way around it. If we know that these abnormal conditions exist, we have to implement a monitoring system to have a broad warning before a catastrophic failure like this happens.” , He said.
The Florida condo building was built four decades ago to an older design and faced compromised capacity due to severe weather, which can lead to erosion and microcracks in the concrete, he said.
“Fortunately that is not the situation we have in San Francisco,” Mosalam said.
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