Miami Beach, Champlain Towers South apartment building collapse, Part 11 54

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 06
Miami Beach, Champlain Towers South apartment building collapse, Part 07
Miami Beach, Champlain Towers South apartment building collapse, Part 08
Miami Beach, Champlain Towers South apartment building collapse, Part 09
Miami Beach, Champlain Towers South apartment building collapse, Part 10


SF Charlie
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[debodine]

To quote rodface: "...I can't imagine that they would be re-used for the new construction in any way, shape, or form..."

If I may share a story told to me by a person I worked with decades ago, so keep in mind I was not personally there. He grew up in Florida and before entering the military worked as a gofer for a construction company. According to his story, the construction crew would dig and place forms for slab homes. When several homes had their forms in place with the rebar set in for pouring the concrete, the inspector would stop by and verify the rebar in place and would sign off that the concrete was ready to pour. Then the foreman and the inspector would walk off and shoot the breeze and drink some coffee while the crew wrestled out the rebar to the next foundation and dropped it in. The inspector would walk over and sign off that the rebar was in place and the concrete ready to pour. Rinse and repeat for the block of homes.

The point of this story, if true, is that there may be other construction firms and inspectors who would use the same process, although I think with the scrutiny this tragedy will receive, I would consider it unlikely.

 

[AutisticBez]

Concrete structures can support larger columns spaced further apart then this. These columns seem to be 2 car spaces in width and 1 long. In major parking garages here in Melbourne, you get them spaced 3 to 4 wide and 2 long. Obviously they are a wider column. We tend to see more of the round style columns.

Build it right. These people died due to excessive cost cutting by the developer right? Gotta make those columns super thin. You couldn't put enough rebar into them without compromising them further.

 

[12345abc6ttyui67]

I think we agree in principle, but over engineering it is not the same as building (or designing) it right.

 

[SFCharlie]

Geophysical methods that send very low intensity waves (e.g., impulse echo and ground penetrating radar) into the ground or the foundations will be used to obtain information about the condition of the foundation and its surrounding soil with minimal disturbance to the site conditions.

So... The are going to radar the foundation. ???

SF Charlie
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[SFCharlie]

Gotta make those columns super thin. You couldn't put enough rebar into them without compromising them further.

Why no just make beautiful spacious columns?

???
Sorry, not a structural, mechanical, nor civil engineer...

SF Charlie
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[AusG]

GPR at several wavelengths for rebar and for shallow voids and structures, Small scale seismic (MASW and/or refraction) for deeper investigation. If they have the time and the inclination they could build a 3D model of the subsurface that way, I assume they are just being thorough. Have we seen any indication a pile moved?

 

[kjm93]

Why no just make beautiful spacious columns?

Modern construction methods for flat slabs use drop panels for increased shear strength at columns, which is basically what your nice-looking column sketch is getting at, but with less complex/expensive formwork and construction.

 

[Optical98]

After they're done with the "investigation", before anything else can be built on the site, I think at least the basin will have to be dug up and removed, honestly everything should go. They need new piping etc.
With having had the dynamite/implosion there is likely damage to the pilings.

And there will be too many eyes on that project to cut corners this time.

 

[SFCharlie]

Have we seem any indication a pile moved?

Sadly, we haven't seen anything. I'll let you all know if I find out anything.


SF Charlie
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[Vance Wiley]

If there is any record of the TOP ELEVATION of the pile caps a quick level survey could tell if there had been a foundation failure from a settling pile group and cap.

 

[AusG]

Yes. For my money a physical survey of the pile caps would be more definitive than any geophysics. If they've moved relative to each other you can start to wonder why then.

 

[raymiepo]

Hello, -would like to state that I'm not an Engr.
Retired General Contractor/Construction Manager.
Been following the thread for quite some time, and have noted that there really has been no in depth discussion about storm water disposal (please correct/direct me if I'm mistaken).
From what I've read, around the time of CTS, Surfside was hurting $$$ for a stormwater disposal upgrade, and the developer fronted Surfside 200 grand so that he could get started with CTS (or something like that).
Anyhow, what looks to me like early submittals (specifically P1 and P2) were marked up by the plumbing inspector. Stated that the Catch basin bubblers were inadequate and probably didn't like the French drain system and to go find an Engineer who could come up with a plan to satisfy Health Dept. and Pollution Control. Revised plans subsequently showed a storm water disposal injection well on the East(Beach) side.
I have seen the 18" storm located in the garage along Col. line 8 in the video of the garage taken by the prospective buyer (note: slight jog in the line to accommodate Bm34). One can also see it in the aftermath video (WPLG Local 10) of the interview of Kilsheimer in which he says he's "...pissed off".
To me it looks like the storm is around 3 ft. south of Col. line 8, and invert at wall penetration around the same el. as the bottom of Bm34 (which according to one of the drawings is +9'-10". The el. of the patio outside at that point would have been around +13', so really not too much cover. Please correct me if I'm wrong here.
Any how, according to the drawing there were to be two 3,000 gal. retention tanks dumping into two 24" square wells, and a total of 8 - 24" manholes.
I can't find 'em - before or after. Nor for CTN, but I see some (only 3) for CTEast which was built in '94 if I'm not mistaken. I think by that time they (the well or wells) would be Class 5 with a French drain filtration before the well for garage and planter contaminants.
And any how, by my calc the wells drawn for CTS would have been around 17' from intake to centerline of well. That puts it pretty close to Col. Line 9.1/10.
The drawing says, "Well depth as required to meet requirement of pollution control section of building dept."
????????
Any registered stamped records Surfside?
Lotta water dumping down that hole.
Well, anyhow, have a look yourselves.
I have only seen a black round something at ground level by the entrance gate to the pool from the beach walkway. Interestingly, I believe that same area is ringed by several cones on the site grid map (Briefing Map) from 7/18/2021.
It would also be very interesting to me if anyone could find info about the North building.
Drilling records?

 

[FacEngrPE]

SF Charlie - Your column looks suspiciously like the Frank Loyd Wright columns in the Johnston Wax Headquarters building. I will grant the are visually pleasing, but they pushed the limits of concrete construction way too far.

 

[SFCharlie]

the Frank Loyd Wright columns in the Johnston Wax

(I didn't mean to claim any originality for the columns.)

In the Great Workroom, the columns expand from 9 inches (23 cm) in diameter at the bottom to "lily pads" 18 feet (5.5 m) in diameter at the top; skeptical building inspectors required that a test column be built and loaded with twelve tons of material. After the test column proved capable of supporting the specified load, Wright had the load progressively increased. Only at sixty tons load did any crack appear.

SF Charlie
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[gonefishing2]

 

[Demented]

Meh. If we have leg lamps, why can't we have leg columns? That'll sexy up buildings.

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

 

[SFCharlie]

why can't we have leg columns? That'll sexy up buildings.

...an image would sexy up this thread...
As for gracious columns... there's a business opportunity here. The forms rental companies could have standard modular graceful column forms. They could come in standard sizes. Also, they might be only for the top, so the contractor could customize the height.

SF Charlie
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[Demented]

...an image would sexy up this thread...
As for gracious columns... there's a business opportunity here. The forms rental companies could have standard modular graceful column forms. They could come in standard sizes. Also, they might be only for the top, so the contractor could customize the height.

Something like this.

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

 

[gonefishing2]

Wonder who(m) will be groping inspecting those columns?

 

[ChiefInspectorJ]

I think we have a joint collapse theory that includes the roof and bottom collapse.
The pool deck collapse caused the collapse of Beam A 's around column 11.1 as seen in TikTok video. This pulled on the column M10 and L10 and beam 33 and 35 and fractured the floor connections causing a torsion in the building and in the top levels of the building which collapsed and pancaked.
The weaker floors started at level 8. The top heavy loads on the roof and the cantilevers and maybe more caused more eccentricity.
The columns on the section at the parking garage under the uncollapsed section show the damage of just the floor shearing off. Thus it did not collapse. The columns were a little bigger but there was no beam there either which caused the initial failure and also saved that part from collapsing.