Pentagon Attacks

[langeweile]

http://www.pbs.org/wgbh/nova/wtc/collapse.html

It was Nova on PBS that had the story of the collapse.

 

[Asterix]

An article from Architecture Week. Essentially the overheated trusses pushed out the outer walls, became detached, and the buildings collapsed like a house of cards.

http://www.architectureweek.com/2002/0515/news_1-1.html

 

[Peeping Tom]

This is not the case, especially when large amounts of stress are involved. There is a safety factor but not overkill. Using a larger than required section of steel increases the likelyhood of cracks, which one most certainly doesn't want in a highly stressed member. Dislocations move throughout the metal and dissapear if they make it to the surface. The longer the distance the more likely it is that they get stuck at a microstructural anomaly. This results in a high localized stress and the probability of forming a crack. This is why wire rope is much stronger than solid section, Likewise for anisotropic structure and monocrystalline metal products.

from what i've heard, the towers, like all buildings were built lots stronger then they need to be.

 

[Peeping Tom]

The towers survived the impact just fine, as designed for, standing for about an hour afterwards. IIRC the impact was more severe than McVeigh's blast in Oklahoma City. The WTC was done in by a massive fire.

..the Towers were not built very long ago, they specifically were built with the possibility of a commercial jet crashing into them.

 

[Cardinal Fang]

This is really getting stupid.....

..the Towers were not built very long ago, they specifically were built with the possibility of a commercial jet crashing into them.

Construction of the building started in 1966 and the building officially opened in 1973. Since the time the construction drawings were approved the state of New York has gone through 5 building code revisions. Each revision strengthened the existing standards of structural design as well as fire resistance ratings between occupancies. The building was designed to the standards of the time.

The building was designed to withstand a commercial jet of THE TIME. At the time the drawings were approved for construction, the 747 was still in design and the 757 wasn't even an idea. As a matter of fact the first 747 to go into service occurred in 1970. The first 757 and 767 was not in service until 1983 and 1987 respectively. The first DC10 showed up in 1983. The airliners of the 1960's were smaller than those of the 1970's with much smaller fuel capacities than today’s airliners.

The structural collapse of the WTC is well documented and most if not all of the important findings have been noted in this thread. The bottom line is that the unique structure that formed the WTC was also its flaw. Oh yeah and the fire didn't help either.

 

[red]

Nootaikok ordered a freezer, but his wife Tekkeitsertok would have Nunavut.

you are blaming the inuit for the WTC collapse?

 

[strange1]

you are blaming the inuit for the WTC collapse?

Look out, the americans are invading the frozen north next.