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World Trade Center
Posted: Sun Sep 08, 2019 12:34 pm
For those of you interested in structural engineering, there is a special on PBS tonight, "Leaning Out," about Leslie E. Robertson, engineer of the World Trade Center.
Posted: Sun Sep 08, 2019 12:40 pm
One of our local PBS stations ran the Pedro Guerrero special the other night; perhaps it's making the rounds again ...
Posted: Mon Sep 09, 2019 9:58 am
Its unfortunate that they didn't incorporate reinforced concrete elevator/service/stair cores in lieu of the multiple drywall solution they ultimately came up with. Would have saved lives.
Posted: Mon Sep 09, 2019 12:02 pm
The hour was a bit disappointing. It was more an apologia and biography than a critique of the WTC. When the project was first published, all the architects I knew were contemptuous of it as design. Yamasaki was not highly regarded by the profession.
One main reason the buildings were built on the cheap was that the owner wanted (as is usually the case) to maximize profit. When they were destroyed, he tried to collect double on the insurance, claiming they were 2 different events. The court found otherwise.
Posted: Mon Sep 09, 2019 1:00 pm
I found the discussion of the elevator and stair towers to be damning with respect to the judgment of the architects and engineers of the WTC.
I had read Minoru Yamasaki worked for Shreve, Lamb & Harmon, the architects for the Empire State Building, earlier in his career. He was aware of the accidental B-25 crash into the ESB in 1945 and the resulting fire with flaming debris in an elevator shaft, and stated the WTC was designed to withstand a Boeing 707 strike. Didn't anyone believe the gypsum board and stud shafts might be vulnerable to high energy impact if survival of a plane strike was seriously being considered as a design parameter?
WTC on 911 was too many things going wrong at once, but the shaft construction was beyond the pale....it allowed the exit stairs, the elevators, and most importantly, the fire suppression riser pipes to be severed in a single swipe.
Posted: Mon Sep 09, 2019 2:30 pm
Is it the case, also, that the joists were allowed easily to disengage from the core and/or the perimeter walls ? I'm trying to recall what I read in earlier reports ...
One wonders if the plotters were aware of the vulnerabilities of the structures---or whether that wasn't an issue for them.
Posted: Mon Sep 09, 2019 6:10 pm
IÃ¢â‚¬â„¢m not certain how much Osama bin Laden counseled the plotters, but bin LadenÃ¢â‚¬â„¢s fatherÃ¢â‚¬â„¢s businesses were large scale construction based. It has been surmised that bin Laden had some knowledge of construction technology and knew details of the WTC garage bombing in the early 1990Ã¢â‚¬â„¢s that was intended to collapse a tower.
Posted: Mon Sep 09, 2019 8:27 pm
The planes hit the buildings at different heights; the consensus at the time was that the collapses were "just lucky" for the perpetrators---as I recall it. I just wondered if there had been any change to that conclusion.
Posted: Mon Sep 09, 2019 10:11 pm
Then thereÃ¢â‚¬â„¢s WTC7.
Posted: Mon Sep 09, 2019 11:59 pm
DRN wrote:I found the discussion of the elevator and stair towers to be damning with respect to the judgment of the architects and engineers of the WTC.
I had read Minoru Yamasaki worked for Shreve, Lamb & Harmon, the architects for the Empire State Building, earlier in his career. He was aware of the accidental B-25 crash into the ESB in 1945 and the resulting fire with flaming debris in an elevator shaft ...
I remember it well, images having been imprinted in my brain, after seeing a News of the World film at our local theatre, not too long after the 1945 accident. It is why initial, early radio reports of the first WTC crash didn't alarm me, too much.
Reading about what actually happened when the plane hit the Empire State Building, and it's elevators is quite revealing. See:
https://wiki2.org/en/1945_Empire_State_ ... B-25_crash
Posted: Wed Sep 11, 2019 9:36 pm
Ã¢â‚¬Å“Dancing IsraeliesÃ¢â‚¬Â� ?