Comment: Also, WTC north tower had a

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Also, WTC north tower had a

Also, WTC north tower had a huge fire in 1975 which burned six floors in 3 hours. 65% of the 11th floor was burned and they were higher temperatures than 911 - above 700F. The flames burst out windows, etc.

This took place at a location which had a much higher structural loading. The beams did not bend and buckle and cause a collapse. No metal was replaced. Even if you want to argue that added damage from impact was the straw that broke the camel's back, you still have to answer why no steel members needed replaced since everyone claims that these temperatures were above 911 where it is claimed the fires weakened and bent the steel>

These towers were designed to withstand fires AND airline impacts. These types of structures are built with high safety factors - i.e., 3 or 4... meaning they can support around 3 to 4 times the loads which are calculated. Even if the steel lost 50% of its strength (which is practically impossible due to the rapid conduction of heat throughout the structure), they would still be capable of handling twice the loading.

If the max temperatures were 600 F, no significant volume of steel would ever get close to that. Only the portion directly under the influence of a flame would even approach it and would still likely be a couple hundred degrees shy. With conduction, steel just 5 or 10 feet away would be much less than that - these are very thick beams and columns.