And then Ostroff got this tell-tale photograph taken on a bright, cobalt sky day in November 2000 with standing water on the pool deck.
That photo was Revelation. It was also redemption for Ostroff, who has keyed, as has this non-engineer blogger, on the pool deck, which also served as the roof for the underground portion of the garage. Redemption because Ostroff had been contacted by other engineers who pointed out in a way that convinced Ostroff that the collapse of the pool deck should not have, and because "should not" "did not," cause two-thirds of the building proper to collapse because of the distance between the pool deck and the garage underneath the building. In the video previous to this Ostroff got a little wild in his conjectures to shorten that distance, gesturing to the first floor fitness center at the connection of the pool deck and the parking garage. It was a small fitness room, not a frigging Gold's Gym. The fitness room had barbells and Nautilus style equipment. "Look at all those weights!" Eh. Bad.
In his latest video however Ostroff points to something much "weightier". Up until 2018 the pool deck planters contained palm trees.
There are six palm trees visible in this photo from Google Street, March 2015. Drawing on his experience Ostroff estimated that the trees would weigh 100-150 lbs per foot and estimated that the palm trees in the photographs were 17'-20' high. Therefore each tree would add 1,700-3,000 lbs to the pool deck. All six of them, 10,200-18,000, so five to nine TONS additional weight to the pool deck. That is enormous.
Notice also the look of the pool deck. With the trees in place the pool deck looked like I had never seen it before, bleached-dry white, like a cattle skull in a desert. The contrast to later photos was so stark I thought maybe it was photographic artifact or maybe the pool deck had been repaved.
This is from the Miami Property Appraiser website, 2017. Not as gray, more to the orange side of the color spectrum, more consistent with the color in more contemporary aerials, but what is not false is the bone dry condition of the pool deck surface.
That is just amazing.
Then the trees were taken out. The trees were removed at the time of this 2018 Property Appraiser's photo.
Still bone-dry.
Ostroff asks the pregnant questions, "Why were the trees taken out?", was it noticed that they were causing overload on the pool deck slab/parking garage roof?, and "How were the trees taken out?" Crane? Was some equipment driven onto the pool deck surface to remove the trees? More weight, tons more weight. It was after the trees were removed that photos of the pool deck began showing clear water staining even on the brightest, sunniest days.
Finally, Ostroff noticed on Morabito's architectural drawing that the garage support posts in Champlain Towers North, the portion that remained standing were a big, fat 24"x 24"; those in the portion of the garage where the pool deck served as roof, 16"x16", and potentially critically, one of them--Just one, why?--but one that was at the intersection of the pool deck slab and the building slab and is theorized by Ostroff to be a key collapsing post, that critical post, M10, was only 12"x12".
Very good work by Ostroff.
This video is titled "What Secrets will be Uncovered at Champlain Towers South Collapse Site? We look at its Foundation," and Josh concludes by saying NIST, the National Institute of Standards and Technology, will uncover those secrets. This non-engineer predicts that NIST will recommend, if they can—require, that engineers build every coastal structure on a foundational tray.
The Building Integrity guy, Josh, takes a deeper dive. He repeats what we must never be distracted from, that it is now beyond reasonable debate that the pool deck collapsed first, triggering a chain. Taking that as given, Josh explores how specifically the chain unspooled. He explores what, if anything, the building's foundation, the system of deep posts in the sand, has to tell us. Josh corrects a misapprehension that the undersigned had, that the foundation posts were set in a structural concrete slab like a tray. They were not and Josh is unperturbed that they were not, apparently it is the industry standard; the foundation posts were like nails driven into the sand, tamped down by an enormous weight suspended from a crane that--I have heard the sound many, many times--Bang! Bang! Bang!--drives the posts into place in the sand. Josh provides convincing diagrammatic and photographic examples of the solidity of these posts, it really it quite impressive. But, having demonstrated that, Josh considers the FIU study of the '90's that showed the building sinking 2 mm/year. That finding would be significant, I've read engineers say, only if parts of the building sank at different levels, that is, only if this end sank more than that end--like if it was mounted on nails driven into "shifting sands," is that what you're saying? That's what they're saying. If the building sank irregularly then there would be stress placed on the whole building, as opposed to if the building sank "regularly" as one unit... So pause there: You're saying only if the sand didn't shift irregularly would the building remain stable. Earth to engineers: "shifting sands"?--their term is "differential settlement" Ho ho ho. Sand does not hold together "regularly".
Important concept to engineers, "Differential Settlement". Yeah! We non-engineers knew that, too!
So important a concept to engineers that,
He actually called a geotechnical engineering company and spoke to the lead engineer 
Okay
Josh took his eyes off the prize, the pool deck concrete structural slab, in this video and got lost in the details of the foundation. He spent nine of the thirty-five minutes explaining "shifting sands" and their implications. What never occurred to him is a "tray" in the sand for the pilings to sit in. A foundational tray is not part of the "standard model" of building engineering. Conceptually, a foundational tray would greatly mitigate, perhaps would remove differential settlement as a cause of structural instability. And engineers use what I am calling "trays" in other parts of the construction of a building.
But this is the way they install the pilings into the sand that those other trays and columns sit on:
This video is titled "What Secrets will be Uncovered at Champlain Towers South Collapse Site? We look at its Foundation," and Josh concludes by saying NIST, the National Institute of Standards and Technology, will uncover those secrets. This non-engineer predicts that NIST will recommend, if they can—require, that engineers build every coastal structure on a foundational tray.
