This individual has been in on forensics examination of just about every major structural failure in recent history.
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's not impressed with the garage flooding at Champlain, says that kind of thing happens all the time and buildings don't fall down. A bunch of disintegrating columns don't mean much to him either. What he is looking for is a trigger event. Something that happened suddenly and shook the whole building. This most obvious trigger event the engineers are looking into is something called "punching shear in flat slabs." These never happen gracefully, they are always instantaneous, and catastrophic. In the case of Champlain Towers, the most likely candidate slab is the pool slab, and it broke loose of its supporting three columns holding up the south facing slab that fell first. The slab must have damaged the column when it fell, and the remaining columns couldn't take the sudden load shift and gave way in succession several seconds apart. Kilsheimer says a description of sounds and events by the lobby attendant are being used as a clue. Other people describe a succession of very loud thunder clap sounds. The three columns under the south face are exactly at the location of known water accumulation draining off the pool deck. Engineering write-up shows flat slab requires double reinforcing at the junction of its column to prevent stress crack formation leading to failure. All the reinforcing at Champlain was almost certainly total rust because of the water accumulation problem.
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