SanderO wrote:You are not aware of the history of the construction of the WTC. For one a bomber HAD struck the ESB and the engineers of the towers DID consider such a catastrophe. They made some effort to engineer the towers to withstand the impact.
No.
They calculated in retrospect, after the design was finished, that (coincidentally, though they probably expected this) the towers would withstand the slicing of perimeter columns along the wingspan of a 707.
It was NOT a design objective that they made any effort towards.
SanderO wrote:This of course they did successfully. There was a lot of clamor about the height, the egress issues and so forth at the time. These structures were receiving a lot of scrutiny and the public and some professionals were not enamored of what they were doing at the time.
Probably right: SOME professionals. What was the consensus?
SanderO wrote:All the developer's PR was about how cool the towers were, how tall, how huge and fast the elevators were, how quickly they were built and how cleverly with an assembly line erector set approach.
Probably right. That was the message for the general public.
SanderO wrote:The architectural community was mostly offended by the design.
What were their reasons for feeling offended?
SanderO wrote:I am not aware of what the engineering community was thinking.
That would be kinda the important group here...
SanderO wrote:The big concern was wind shear.
I am not aware that wind shear turned out to be a real problem. None that was a factor in the eventual collapses at least.
SanderO wrote:Recall that the CitiCorp tower was another ticking time bomb which WAS retrofit when the engineer who had a conscience admitted that he had not considered the forces from a 100 year storm and that the wind shear trusses would fail and the tower come down. The retro fit was a face against the hurricane season. Another crazy design over an existing structure which huge dramatic cantilevers...
Yes, kinda reminiscent of ozeco's big dam war story. So they fixed the problem, they (owner, designers) settled on the financial responsibility, and that was that. Accountability? Yes. Rolling of heads? No. Perhaps as it ought to be.
SanderO wrote:We're not exactly talking hindsight here. Engineering and architecture are about PLANNING and that does involve a lot of *what if* examination.
Yes, and at some point, the buck must stop and the building gets erected.
Like I told uglypig: You can't plan for and successfully design against every possible catastrophe. With 20/20 hindsight you might have done some things different wrt to plane attacks. Still, the plane attacks would have killed many people and totalled the towers, no matter how you build them. The key to significantly improve stuff would not have been to make them safer from collapse, but to provide for more and better egress options.
There is an earthquake with a probability >0 of happening that will flatten every building in NYC. There is an asteroid with a >0 probability of hitting Manhattan. And there is a terrorist plot with a >0 probability of getting carried out to every high rise that will bring it down. To some of these risks, there is no realistic solution, and to some others, the solution lies not in making the structure stronger.