Having--justifiably--trashed this report with the lede alone I must be honest. It seems to the engineers that the collapse of the pool deck concrete structural slab is insufficient alone to bring two-thirds of the entire building down. The engineer whose video, titled "The Cause", I wrote about and posted did a follow-up video and says on that follow-up that other engineers reached out to him and pointed out that the pool deck collapse would not have pancaked two-thirds of the building. Jon Osoff, I believe his name was, took those professional corrections seriously and his follow-up is less categorical. And, as Mr. Batista says below a dead rotten tree can fall in the forest suddenly and with no nudge. But, continuing my metaphor, one tree falling is not going to bring down the entire forest. In Batista's words he has seen sudden, no-warning collapses before, but never two-thirds of an entire building suddenly collapse. Never is a long time.
Mr. Osoff was also honest enough to correct himself about the location of the five critical pillars in the underground garage that he believes fell after the pool deck (the underground garage ceiling) fell leading to the collapse of the building. In the video I posted he had those posts closer to the pool area. In fact they were farther away. Which makes the pool deck solo theory more attenuated. I trust the experts. Since they are hesitant about the pool deck solo theory, I am.
I have to ask the experts though to examine any "other cause" theory they may entertain from the reverse angle. Since, as even this Miami Herald article says "the pool deck slab was known to have failed first" the same attenuated causation that makes them squeamish about the pool deck solo theory would have to apply in reverse. That is, if a, or several, critical support posts in the garage buckled and collapsed how would they have caused the distant pool deck to collapse when the distant pool collapse didn't cause the garage posts to collapse? A garage support post theory would have brought down the center of the building alone, no? Why would the pool deck have collapsed in addition? And (I have to remind myself to believe the experts) but and, does it not give any "other cause" theorists pause that it is now taken as a given that "the pool deck slab failed first"? You can't reverse chronology in a reverse angle analysis. Another and: Are we now talking about five DUI drivers hitting the five critical posts? A fucking demolition derby inside the garage at 1 a.m.? Or five explosions? Come on. I am going to make an exception to my "trust the experts" default: Professor Dawn Lehman. Professor, go the fuck away, you are a fucking idiot.
There may be something else working on the experts at a subliminal level: the integrity of the entire engineering profession This building was built in compliance with then-code and per a standard, tried-and-true engineering template for the tropics. Structures, like constitutional democracies or condominiums, that have lasted for years don’t just COLLAPSE. A sudden collapse threatens the whole standard model, whether of buildings in Florida, or democracy in America.There has to be an outside cause. Except there doesn’t.
Finally, this is bullshit by the Miami Herald. That lede is irresponsible. There was no fucking explosion, the Herald even says an explosion (there would have to be several) "demolition-style." That is utter irresponsible bullshit. As I mock below, neither was there a "missile" ("like a missile": an early witness) or an exploding car accident in the garage (what another witness thought the noise sounded like), or a fucking earthquake (other witnesses). Mr. Batista states the obvious, that the collapse of the pool deck concrete structural slab "of course" is going to produce a "boom".
Panicked Surfside 911 calls show clearer timeline of collapse, suggest possible explosion
...the pool deck slab was known to have failed first.
[T]he emergency calls... provide a clearer timeline of events.
1:16 a.m., a breathless caller reported “a big explosion” at Champlain Towers South.
1:16 a.m. a fire alarm service called in an alarm for the building.
1:17 a.m. “It seemed like here it was an earthquake. The garage, everything — seemed like something underground — everything exploded down.”
1:21 a.m...someone reported the debris cloud — which the caller described as “smoke” — ...engulfed bystanders as half the building collapsed, demolition-style.
1:23 a.m. another caller, who originally phoned Miami Beach police to report that “the roof collapsed in the garage,” according to the recording, instead yelled to the county dispatcher “Oh my god. The fucking building collapsed.”
A few minutes later another shaken caller said she witnessed the pool area collapse. “I woke up because I was hearing some noise, I couldn’t understand what was happening. I look outside and I saw the patio [pool] area, started sinking down.” She said she saw the “whole building” fall underground. “There are many, many floors of the building that went down, the building just went to the sinkhole,” she said. “So there will be many, many people dead.”
Experts interviewed by the Herald said those words — “explosion” and “earthquake” — hint at a possible trigger that could have caused the collapse of the pool deck slab…
[Don't forget "missile"! Don't forget "accident"! Don't forget DUI driver!]
“If there was an explosion — and I don’t know what could have caused it — but that could have caused that slab to fall,” said Dawn Lehman, professor of structural engineering at the University of Washington. “That could have started the progression [of the building collapse] as we know it.”
“All of this makes a lot more sense to me. Because nothing else made sense to me,” Lehman said. “An explosion shatters concrete, unfortunately, just like we saw in Oklahoma City.”
Lehman said gas lines or fuel tanks could have ignited and caused enough force to take down a structural element of a building like Champlain Towers. Then the slab falling could have caused a sound and vibration like an earthquake, she said.
Other engineers cautioned against drawing too many conclusions from the specific words used in the emergency calls.
Greg Batista, an engineer from Davie who specializes in concrete repair projects, said the “explosion” described by 911 callers could have simply been the sound of a concrete slab falling into the parking garage.
“It’s more likely than not that when the slab falls, of course it’s gonna create a loud boom,” Batista said. “You’ve got tons of concrete falling down at the same time.”
He also said an electrical explosion is unlikely to have triggered the collapse, unless it occurred near a gas tank and set off a chain reaction.
Building plans do not show obvious gas lines in the basement, however a memo from the condo manager last year described a dilapidated fuel tank near the entrance to the garage — a storage location Batista called unusual for potentially flammable materials like the fumes from diesel fuel.
Frank Rollason, director of the Miami-Dade Office of Emergency Management, said his office has received “no information and no intel, and there’s been no discussion that there’s been an explosion of some type that caused that building to come down.”
Allyn Kilsheimer, a structural engineer hired by the town of Surfside to investigate the collapse, said an explosion is “on my list of possibilities” for what could have ultimately caused the building to fall.
Drawings for remediation work that was put out to bid earlier this year showed that gas service was set to be installed at the building, Kilsheimer said, but he said he doesn’t believe the building had any gas service when it collapsed.
The ultimate trigger will not be certain without a full investigation. Still, buildings usually don’t just fall without a nudge, regardless of their state of disrepair, experts say, making the sudden, unexplained, middle-of-the night Champlain cave-in appear unprecedented. But explosions — of gas lines or otherwise — have triggered collapses in the past.
Still, it’s possible, Batista said, that there was no particular trigger — other than years of structural problems and deterioration over time, including concrete cracking under pressure, that caused columns to give way.
“I’ve personally seen in projects that I’ve worked with that these things just collapse at a moment’s notice,” Batista said. “But nothing remotely to the extent of this damage.”
Even if the trigger for the slab failure was identified, experts say, it still does not explain why the structure on top of it subsequently came down. Lehman said a question for investigators remains: “How could we have saved the rest of the building from collapsing.”
