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originally posted by: waypastvne
This is a truss seat. It has a structual capacity of 94.000 pounds. If that is exceeded.....it fails.
originally posted by: neutronflux
a reply to: kloejen
You
I repeat, "simultaneous failure of every column in the building", please neutronflux explain that?
which was their conclusion, and you have avoided so far?
I addressed it in my first post and other posts...
originally posted by: Box of Rain
originally posted by: UnearthlyEarthling
...Thermite. The colour of the liquid indicates its burning at over 1000 degrees celcius. A higher temperature than what just fire can achieve.
How did ancient civilizations melt iron, bronze, and copper at temperatures of 1300 degrees Celcius with just fire?
The answer is they used bellows to blow air into the fire. The oxygen in the blown air would enhance the fire, making it burn hotter.
I can image the higher winds the are present as you go higher up a building could produce a bellows effect on the inside of a burning building (especially via air rushing into broken windows and other openings), stoking the fires in the building with oxygen to make them hot enough to melt metal -- like an ancient metal smelter.
originally posted by: Salander
To claim that small fires on the upper floors could transmit heat through the structure sufficient to melt the lower floors is the sign of a very poorly informed mind, or perhaps just plain old deception.
originally posted by: kloejen
No u did not, YOU posted some dribble, that is not even concerning the question how all core columms somehow disapperead simultaneously in WTC7.
They are located here.
originally posted by: Salander
a reply to: waypastvne
No, 19 years ago the government and media asked me to believe that small fires on the upper floors were what caused a universal collapse at free fall speeds.
Thankfully Kevin Ryan pointed out the obvious. Steel is a poor conductor of heat and the official story was nonsense.
Do you still believe that bull# story?
By now, this is going on into the afternoon, and we were concerned about additional collapse, not only of the Marriott, because there was a good portion of the Marriott still standing, but also we were pretty sure that 7 World Trade Center would collapse. Early on, we saw a bulge in the southwest corner between floors 10 and 13, and we had put a transit on that and we were pretty sure she was going to collapse. You actually could see there was a visible bulge, it ran up about three floors. It came down about 5 o’clock in the afternoon, but by about 2 o’clock in the afternoon we realized this thing was going to collapse.
All materials weaken with increasing temperature and steel is no exception. Strength loss for steel is generally accepted to begin at about 300°C and increases rapidly after 400°C. By 550°C steel retains approximately 60% of its room temperature yield strength, and 45% of its stiffness. At high temperatures, steel is also subjected to significant thermal elongation, which may lead to adverse impacts, especially if it is restrained. It follows therefore that one would expect that structural steelwork which has been subjected to high temperatures would exhibit signs of this in the form of distortion and buckling.
The tensile strength reduction for grade 4.6 bolts is similar to that for grade S275 steel. For grade 8.8 bolts, which are heat treated in manufacture, the residual strength reduction is more marked if the material temperature has exceeded 450°C. The residual strength of these bolts falls to 80% and 60% after reaching temperatures of 600°C and 800°C respectively.
originally posted by: carsforkids
a reply to: waypastvne
how they sit on top of the outside bearing walls.
How did the collapse of WTC 7 differ from the collapses of WTC 1 and WTC 2?
WTC 7 was unlike the WTC towers in many respects. WTC 7 was a more typical tall building in the design of its structural system. It was not struck by an aircraft. The collapse of WTC 7 was caused by a single initiating event-the failure of a northeast building column brought on by fire-induced damage to the adjacent flooring system and connections-which stands in contrast to the WTC 1 and WTC 2 failures, which were brought on by multiple factors, including structural damage caused by the aircraft impact, extensive dislodgement of the sprayed fire-resistive materials or fireproofing in the impacted region, and a weakening of the steel structures created by the fires.
The fires in WTC 7 were quite different from the fires in the WTC towers. Since WTC 7 was not doused with thousands of gallons of jet fuel, large areas of any floor were not ignited simultaneously as they were in the WTC towers. Instead, separate fires in WTC 7 broke out on different floors, most notably on Floors 7 to 9 and 11 to 13. The WTC 7 fires were similar to building contents fires that have occurred in several tall buildings where the automatic sprinklers did not function or were not present.
The trusses are not sitting on top of the bearing walls. They are sitting on a truss seat that is welded to the side of the columns. The welds failed when they were overloaded. A cascade failure ensued.
originally posted by: carsforkids
Bet ya a dollar to a donut the joists in the other pic are sit'n on
the outside wall.
originally posted by: carsforkids
The joist is at the bottom of the pic.
Gross and McAllister (Ref. 3) dis- cussed the probable collapse sequence, based upon experimental work and finite element analyses, for the WTC towers that specified the main structural events lead- ing to collapse initiation; the reader is re- ferred to that document for details leading to the collapse. Immediately after collapse initiation, the potential energy of the structure (physical mass of the tower) above the impact floors (94th to 99th in WTC 1 and 77th to 85th in WTC 2) was re- leased, developing substantial kinetic en- ergy. The impact of this rapidly accelerat- ing mass on the floors directly below led to overloading and subsequent failure of these floors. The additional mass of the failed floors joined that of the tower mass from above the impact area, adding to the kinetic energy impinging on the subse- quent floors. The failure of successive floors was apparent in images and videos of the towers’ collapse by the compressed air expelled outward as each floor failed and fell down onto the next. This mecha- nism appears to have continued until dust and debris obscured the view of the col- lapsing towers.
originally posted by: kloejen
originally posted by: neutronflux
a reply to: kloejen
You
I repeat, "simultaneous failure of every column in the building", please neutronflux explain that?
which was their conclusion, and you have avoided so far?
I addressed it in my first post and other posts...
No u did not, YOU posted some dribble, that is not even concerning the question how all core columms somehow disapperead simultaneously in WTC7.
And you black and white text screen aint gonna prove nothing.