Posted 09-08-2004 at 14:31:20
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Yea I saw it. Saw it before and made a point to watch it again. However I didn't take away from it what you did.
I saw a marvel of a building that had never been constructed before. Imagin construction something a 1000 feet tall to withstand a fully loaded 707 flying into it at 350 mph. How they remain standing after the planes had all but cut one wall out is almost beyond belief.
I didn't buy the floor truss thing. I have enough understanding about construction to know that, by design, they are made to pull off the outer wall when they fail. The idea being they don't want failing floor joist pulling the walls (vertical support) in if they do fail. Again they are "designed" to do that. Somewhere, somebody, at some point, calculated how many they could loose and remain standing. Why didn't they have that in the program.
From a fire protection stand point. You can delay the effects, provided it remains intact. Idealy till the fire burns out or is put out. Don't recall the date but 20-30 years ago a high rise caught fire mid way up. Burned hot enough to melt steel and burned for days. It didn't fall. Poor design? I don't think so. I think it worked pretty good. Did some of the fire protection on the trade center get lost in the impact? Yes. Did it all? No. One of the survivors above the impact, stated that he could see fire between gaps in the drywall as he went down. So some had to remain. Where a 767 traveling 450 mph tore it off is where it failed. I don't know of any fire restance material that gonna survive that. Short of 12" of concret. But that is a problem in and of itself. Like before - Somewhere, somebody, at some point, calculated how long and intense a fire could burn before things started to fail. Why didn't they have that in the program.
I suspect the actual problem (from a "why they fell" stand point) was a combination of damage and not poor design. Loss of suport (outer wall), heat damage to said walls, and structal damage to the walls. Remove 1 and they'd still be standing.
Take the south tower. We know it would stand on less than four, because it did. The path of the plane litteraly took out the 1/2-2/3 of the south wall. And it remained standing. We know that with the east walls damaged (floor trusses missing when plane took them out) it still stood. Because it did. So with part of the south missing and the east damaged it still stood. We know the building was designed to survive a fire. Others had. So what did it? Was it impact, trusses or fire or a combination? I say a combination. But the program focused almost sololy on the design - trusses and loss of fire protection. Knowing what happens to steel when it gets hot. And knowing the massive amount of weight the vertical supports carry, I tend to lean that way. As uprights sucumed to heat, the others couldn't carry the added weight and buckled.
I don't know all the numbers, but there is a point of no return. A build of convention construction, concret center, uprights on 30' centers, etc. most likely wouldn't have survived either. With the exception of a concret center they use the same fire profing. I seroiusly doubt they even would have survived the impact. They by design are more ridged and not made to sway. Out west tall conventional buildings sit on springs, shocks, or both to absorb the effects (swaying) of quakes. Had the towers been constructed that way on hard bed rock (no quakes in NY), they would have most likey buckled rather than absorb the hit thus killing the 15,000 that were estimated to be in them at impact. Did you notice that all the windows on the ground floor were broke. Some serious twisting going on there. I say given the conditions they preformed way beyond expectations and saved thousands of lives.
As for the designer, I didn't get the feeling he was feeling guilty per-say. He was sad that his greatest achivement in life was gone and the loss of life just added to it. But mabey I miss something he said I did get up and visit the fridge a couple times.