This will be a pretty interesting study for the forensic engineers out there,  Damn thing looks like the Murrah building with that whole side collapsing like that.  The videos that I've seen don't give much insight either, it just starts to slump and that's it.  I'm no engineer, but the steel structure that you can see in a few pictures looks pretty light...  A structure with the minimum amount of redundancy built in, and a construction mishap, well, I guess I'll leave it to the professionals.

So, all the hard rock was above ground, in this case.

!

I saw a report where someone said, just before the accident, they had lifted a swimming pool onto the roof.  The pool looked like a large mass of steel (but could have been concrete).  Those steel columns still visible on the top two floors would have been too small to carry that size and type of concentrated localized load. But we'll see.

It would be interesting to get the followin information:

1) Was there a construction staging plan that was coordinated, reviewed, and "approved" by the Engineer of Record (EOR).

2) Was the shoring reviewed by the EOR?

3) Was the shoring installed per the "approved" shoring submital?

4) Was the Cast-In-Place (CIP) concrete of addequate strength at the time of construction loading?

5) Was was the firm conducting special inspections on the CIP concrete providing competent services?

6) Did the concrete change its properties/strenght between mixing and the pour? Were there whether conditions that contributed to this?

Forgot to include #7:

Were the loading assumptions correct? Did the GC adequately and clearly communicate what loading was gling to be taking place when abd where to the EOR during the shoring submittal review? 

Crane demo newspaper graphic:

https://www.enr.com/articles/47900-controlled-demolition-of-tower-cranes-planned-at-site-of-new-orleans-hotel-collapse

Earlier in the week, officials abandoned an earlier plan to use support cranes to dismantle the unstable tower cranes after determining that plan was unsafe. “The largest crane company in America is here and wouldn’t touch it with their cranes. This is how dangerous these are,” McConnell said Thursday.

https://www.nola.com/news/article_f8eb5d78-0590-11ea-894e-53fa0f93d837.html

The implosion should take place in about nine weeks, Fire Superintendent Tim McConnell said at a news conference Tuesday — though he said the College Football Playoff championship game, scheduled to be played at the Mercedes-Benz Superdome on Jan. 13, could delay it slightly. Three months of cleanup are likely to follow the implosion, McConnell said.