Quote:
Originally Posted by BrodieMSU
If you are trying to compare the collapsing time of a bridge and a tower building, its completely offbase. Those are two completely different structures, with two completely difference failure mechanisms.
|
A bridge with essentially TWO supports takes 4 seconds to fail because ONE truss was lost and progressed to the others... Progressive collapse, far less supports, smaller safety factor due to age. Why the delay? Why not instant failure like the THREE WTC towers? Why not ignore the intact resistance like in the WTC?
WTC towers avg. 10 seconds to collapse (NIST) because of (officially) a truss failed overloading other trusses and causing them to fail, the causing all the columns to fail even in 70 untouched floors and causing global collapse in < 11 seconds in both cases.
IDK... seems like the bridge should have collapsed in < 1 second per. 9/11 gravity magic.