Re: Christian Theologian says WTC towers were demolished, cites evidence
oh man. i stayed outta this thead for a reason, but i have a background in architecture and graduated from the university of which one of the designers of the new freedom tower and complex taught. maybe i can help sum it all up.
i have heard a couple of conspiritors site similar articles and stories much like the original post of this thread. they make for interesting reading, but don't hold much credit.
i watched that eventfull day live on tv from shortly after the first plane hit. I got a call from a friend of mine from the UK who told me to turn on the tv and that a building was hit by a plane. my first responce was "did it fall over." all i got was no and go turn on the tv. i knew that if the initial impact couldn't take the building down it was going to stay up. from there i sat with the rest of the world watching the events unfold. i too was amazed at how "cleanly" (for lack of a better word) that the buildings fell. i have personally witnessed a building being imploded and it was very similar. because of how cleanly the two buildings fell it is easy to believe a lot of the stories of external forces other than the planes taking the buildings down.
lets me just start off saying that NY is one of the most difficult states to pass the licencing exam for architecture, mainly due to extra questions having to do with the structure of skyscrapers. on top of that, the united states has some of the worlds most difficult codes to enforce as far as construction, building, and life safety are concerned.
there are a couple of factors that have to be addressed when designing a building of this size/height. the first are the loads involved, but i will try to simplify it. there are dead loads and live loads that make up the weight of the building itself, all the furniture and occupants inside, and any snow or water sitting on the building. these loads are easy to understand because they are based on gravity only for the most part, and all the energy is going to be pulling down. there are also windloads that become a major factor for any building of a substantial height. these loads get really tricky to work with. basically the wind is going to always want to push the building over. because of this the building needs to have a little play, or a little bit of room to sway. if this building or any building for that matter was built totally rigid, the suttle movement would eventually start to crack portions of the building and the structure would fail. so in order to create some looseness in the building you will have two types of connections at all structural points. solid connections and pin connections. the pin connections hold structure from forces like gravity pulling the building down while at the same time allow for a little sway with the wind. in NYC the code says that buildings also have to be designed to withstand a crash from a 727. the planes that hit the WTC were not the first planes to hit a building, and not the first even for NYC. back in the 1920's or 30's a small plane crashed into the empire state building starting a large fire and killing a couple dozen. i don't know a lot about how the loads are calculated or distributed through the building in the event of a plane crash, but i would imagine that the exterior frame and sheathing of the building has more to do with it than the internal structure of the building. i'm not going to try to explain this one since i don't know much about it, but like i said before, the building should have been designed to deal with it. Now the design of the WTC buildings were fairly momentus for its time. they were the second and third largest buildings in the world once completed. using newer forms of construction where the stucture was kept internally and not all along the outter walls was the way to go then. but due to the height of the buildings they had more structure on the exteral skin of the building than most of the buildings of their time. this skeleton of structure generated the lines and design that was the building. i don't think anyone could say that these buildings were built unconventionally or in a flimsy manner. hopefully that sums up the structural portion.
now lets move on to fire codes and life saftey, of which, again the USA has some some of the strictest in the world. all buildings have firewalls and those walls have fire ratings. the fire rating is controlled by an independent comany that does nothing but try to figure out how long certain construction details will burn before getting destroyed. then you factor in that anytime you have a building over three stories the building has to be sprinklered or fitted with some sort of fire suppression system. the prinipal of the fire wall is to contain fire to the smallest area, and keep areas of escape and rescue clear of fire and smoke for as long as possible until the fire is under control or put out.
With this background info it should be a little easier to understand what happened.
first off a large plane hits the building. you have a force similar to a wind force in that it is from the side. this kind of force is the end all kinda force that the terrorist hoped would topple the building over causing a domino effect of destruction that would have made the current hole in the ground cover most of southern NYC. knowing that the initial force of the plane wasn't enough to tear it down it was fairly safe to say that the building wasn't going to go down. therefore you get what we had with fire crews still entering the buildings and confusion as to how safe the buildings were. now fire breaks out. not just any fire but jet fuel fire like you all know. it burned out of control at at least twice the temp of a standard fire. this could have been, and probably was the downfall of the building codes. the codes were based on fire, not high octain fuel fire. another section to the fire code is that structure can't be exposed. the point of this is so that you wouldn't have fire melting structural connections. unfortunately the jet fuel burned hot enough to reach certain structural connections and melt them. possibly through the concrete that surrounded them as protection.
what you end up with is a couple of factors that lead to disaster. once the fire melted the pin connections (see above) near the exterior walls of the buildings they probably melted out fairly quickly. due the nature of a pin connection they are usually not the strongest connection anyway. once these structural connections were broken the sway of the building was no longer being held together by the pin connection. so you end up with all the other structural points (along the inside of the building) moving in ways that they were not designed to move. once one floor or level gives way the loads associated with live and deadloads start moving. once these forces start the building is done for. so you take one floor of the building that falls with all the pin connections at the outter walls melted away and you end up with a very clean teardown. the areas where the pin connections were found were the connection between the rigid frame of the exterior and the rigid structure of the internal skeleton. once they failed the internal skeleton fell under the pressure of the floors above while the outter rigid walls stood until they were dragged down by the internal portions of the building.
i feel that the conclusion reached by the officials involved made a lot of sense. in times where the world is literally stuck with its pants down people will always look for additional factors or causes. at the end of the day it was a safe building, it was unfortunate that there was a comunication breakdown that lead to so many deaths. RIP