Miami Beach, Champlain Towers South apartment building collapse, Part 06 131

[SFCharlie]

A continuation of our discussion of this failure. Best to read the other threads first to avoid rehashing things already discussed.
Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse, Part 02
Miami Beach, Champlain Towers South apartment building collapse, Part 03
Miami Beach, Champlain Towers South apartment building collapse, Part 04
Miami Beach, Champlain Towers South apartment building collapse, Part 05

SF Charlie
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[Demented]

Nothing in particular. I'm just trying to understand why there's worry over the columns on both properties along the CCCL.

Precision guess work based on information provided by those of questionable knowledge

 

[Demented]

T.O. Basement Slab (8”) : +2’10

T.O. Concrete Framing Basement: +2’2

T.O. Footing: -2’2

B.O. Footing: = Depth of Pile Cap

T.O. Pile: = B.O Footing +4”

B.O. Pile : As required

I thought the basement slab was 9" or 9.5"?



Also *scratches head*

edit: Nevermind. *Bangs head on desk*


Precision guess work based on information provided by those of questionable knowledge

 

[Optical98]

Can anyone clean this video up? Look at all of them down there at 2:52am, 7/7/21.

Link

 

[Demented]

Can anyone clean this video up? Look at all of them down there at 2:52am, 7/7/21.

Link

They were digging a trench by hand all night basically.

https://www.youtube.com/watch?v=1O8Ydaegba4

Precision guess work based on information provided by those of questionable knowledge

 

[SFCharlie]

Can anyone clean this video up?

It's probably an outtake from:
Champlain Towers South Search and Rescue - July 7


SF Charlie
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[Santos81]

I thought the basement slab was 9" or 9.5"?

I’ve seen 8, 9, and 9.5” specified along with multiple elevations for T.O. Basement Roof (Slab).

Regardless of that elevation value, T.O Footing is -5’0 from there, with B.O. Footing as specified per pile cap depth.

We’re working on 3d Models to map out as built incorporating all the individual unit changes where applicable to aid in reconstruction. Having viewed the full footage from multiple cameras at 87 Park today, only makes that more difficult and important.

 

[lucky555]

I stumbled onto this tour of the Champlain NORTH building's parkade, might be worth a look. Innermost and a few other columns look bigger and the ramp area does have a strange raised slab for the generator room.
[URL unfurl="true"]https://youtu.be/QbjRUvCGRXc?t=574[/url]

 

[apper.42]

Another partial collapse in North West Miami Date today, looks as if it may be a wood structure in the photo but too far away. Only a three storey building but if it is wood then usually it does not fail suddenly; Things are getting very interesting in Miami Dade area. See previous post by jbourn8.

 

[spsalso]

Who says the wood structure failed suddenly? It could have been failing for months or more. There even could have been plenty of outward indicators.

It fell DOWN suddenly, but that's gravity for you.


spsalso

 

[apper.42]

OK sparky calm down a bit; news said it was re[ported that it suddenly failed. Over what time exactly we may find out later, as far as I know there is no reported video so far.

 

[Auri]

Definitely looks concrete. Whaddya know, a big cantilever section fell unprovoked

https://twitter.com/i/broadcasts/1m...rtial-roof-collapse-miami-dade-205356535.html

17500 NW 68 Avenue

 

[apper.42]

Yes a different video shows that it probably is concrete; according to the mayor it had had its 40 year inspection almost 10 years ago which jives with the first report that the building was built around 1970. The 40 year inspection apparently revealed no concerns. Residents have been evacuated. Possibly someone should open another thread on this failure.

 

[Santos81]

Definitely looks concrete.

Definitely 100% wood frame.

 

[CE3527]

I've seen those referred to as either mansard roofs or false mansard. The actual structure is concrete, but this wooden false roof sat on top of it. A lot of times these get added to existing buildings for curb appeal. Could have gotten blown off or just wood rotted away.

 

[apper.42]

"CE3527 [I've seen those referred to as either mansard roofs or false mansard. The actual structure is concrete, but this wooden false roof sat on top of it. A lot of times these get added to existing buildings for curb appeal. Could have gotten blown off or just wood rotted away."

Or the attachments of the wood to the concrete failed. My first attempt at using a quote and not too great. Weather it rotted or just blew away it should not happen and could easily kill people, why was it certified is the question and obviously closer inspection intervals are required. Was the concrete or anchors deteriorated, was the wood rotten, was it a poor design?

 

[Santos81]

I've seen those referred to as either mansard roofs or false mansard.

Cockloft is much more appropriate for more than one reason.

 

[apper.42]

They are definitely going to require more competent engineers and building officials in Miami-Dade and possibly other parts of Florida. Unbelievable!!

 

[AusG]

To keep the two events apart and discussions on-topic I have made a new thread for the NW Miami Dade false roof collapse.

https://www.eng-tips.com/viewthread.cfm?qid=485365

Not matters of equal importance by any means but hopefully there will be lessons learned from even this.

 

[Demented]

I’ve seen 8, 9, and 9.5” specified along with multiple elevations for T.O. Basement Roof (Slab).

Regardless of that elevation value, T.O Footing is -5’0 from there, with B.O. Footing as specified per pile cap depth.

We’re working on 3d Models to map out as built incorporating all the individual unit changes where applicable to aid in reconstruction. Having viewed the full footage from multiple cameras at 87 Park today, only makes that more difficult and important.

I think what will be found is the piles don't go down nearly what is thought.

All I find are 3'6"and 48". Precast 14"x 14" or as drawn to scale, 13"radius, and 50 tons.

You're not driving 42' or 48" long piles to 50 tons that shallow unless you're. constantly back filling with sand, rock, dirt, wood, rebar, someone's hardhat as a joke, etc.

I still haven't found anything else that calls out dims for the precast piles.
We've seen the other construction flawns. Hell, that odd 2" section in places on the core drills can easily be explained by the drawing issues.

Fuckin typos man.


Precision guess work based on information provided by those of questionable knowledge

 

[w-streng]

Hi Demented

Those depths you mention refer to the pile cap itself.

Pile depths - Given the 'bulb' at the bottom of the pile (shown on the drawing), this would indicate that these are driven, cast in-situ piles (Franki). Crudely explained, a steel tube (more or less 20" dia) is driven down until it reaches a point when the displacement of the tube is minimal (probably down onto the limestone). They then anchor the tube to the piling rig and continue dropping a hammer inside the tube, now displacing a dry concrete mix placed in the tube, to create the bulb. A rebar cage is dropped in and concrete or grout is poured in. The steel tube is then pulled out.

Where they call off 'tension' piles, they ensure that the reinforcing cage is linked into the bulb forming an anchor.

These driven piles are usually quite reliable and shaft stresses are quite low (limited to around 800PSI).
Settlement of piles would show up as differential settlement between columns and be noticed long before a collapse. Safety factors on piles is quite generous.