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JimmyP80 said:Debris is visable inline with the first column after the ramp (M8 or L8?)
warrenslo said:No, there are three forces in a column, slenderness, punching, and axial.
warrenslo said:There was clear deflection in unit 1010 prior to collapse
DB27 said:As previous posters stated, this slab was acting as a diaphragm to transfer lateral loads for the building and I would expect the connections to the exterior wall to be important to properly transfer those forces.
warrenslo said:The pool deck collapse relies on a theory that the pool deck collapsed and the columns adjacent were exposed and failed, they fail to recognize the pool slab stepped 2-4 feet at these columns and the slabs were not continuous.
dold said:'...
Looking at the video it appears that the column on grid I/9.1 was the first to go, although I can't see the interior columns to the north.
...
1) this looks like a low point (+10'-10" only open to the pool area to the east) where the slab would seem to be at higher risk of corrosion. ;
2) there is a 2'-6" step in the slab at this column joint.
2.a) this leaves a decent offset between a potential lateral load implied by a failed slab panel (possibly yellow area?), and the restraint at the primary deck at +13'-4".
...
Next, perhaps since all the columns along grid 9.1 are tied together with a beam at the slab step, if column I/9.1 (i.e. "the suspect column") collapsed first, that could potentially mobilize a force on grid 9.1 columns acting to the west, with load path bonus from the steel in the perimeter beam.
This seems to be reflected to some extent in the collapse video - the columns along grid 9.1 are among the first to go, starting at the suspect column and propagating east.
warrenslo said:otherwise the pool would have fell slightly as well.
warrenslo said:To date there is nothing I see conclusively stating the parking/pool deck collapsed FIRST. Every witness didn't have a clear view.
warrenslo said:And, I've always been taught to calculate punching as part of a column. Otherwise why are column caps centered around columns? Seems like you are being protectively picky...
Beginning to think there are shills on this forum...
warrenslo said:There was clear deflection in unit 1010 prior to collapse, the mislabeled column I found (see post above) is between the coat closet and laundry in the photos below - this deflection is more than normal in concrete (in steel is this is more normal in a long span.)