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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[CE3527]

Based on the deformation near the door frame in the unit 711 Ring video, I think it's very likely that anyone in the 11 stack, including 811 could have had difficulty opening their front doors. We do know that 111 and 611 got out so maybe it was some but not all doors.

Pretty clear that the failure and most commotion was originating along the 11 stack, so while some heard/felt the failing structure and escaped, maybe others heard/felt and were unable. The units further away from 11 would be hearing and feeling less and less before the collapse.

It's a pretty grim topic, not trying to overlook the tragedy for those involved.

 

[arbitraria]

Just curious, does anyone know what kind of doors they were?

According to the door schedule, the original doors were solid core wood with steel jambs. I read somewhere in meeting notes from the condo association that they were considering options for new unit doors, I think as part of the overall package they were starting when the building came down.
I'll have to see if I can find it again. Though I would think over 40 years they may have been replaced already, since condos like to upgrade common areas and corridors to avoid looking outdated.

 

[Demented]

You’re right on the money…no pun intended.

UPH required revisions to Foundation, Basement, Lobby, Second, and roof levels specifically for wind load resistance. The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb. Legitimizes the rumors regarding a bought it yet to be obtained variance while simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations.

I'm sure you've noticed the different signatures on the different 2nd floor framing plan drawings too. I've found 4 different S6 sheets in total.

Edit:
"simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations."
Eh, not quite. There's still the possibility of fabrication shops having fabricated rebar cages off of the original unrevised copies.
Gotta love change orders.

The mess with the pile changes even, with changes up to 2 months before ground breaking. I'd put $100 on both the revised and unrevised copies being in workers hands on that site.

If you're just referring to the engineering, then ignore me.

Demented

Quote (Vance Wiley)
I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?

"-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels."

^ This could explain the brief pause at the 8th floor?

I'd suspect differences in rebar being a more likely factor. You can hear the rebar in the 711 video under tension before the shearing failure began and before the cascading clapping of the collapse.

S/T= and then refer to the charts.

Additional compressive strength of the lower concrete definitely could have helped initially resist, or perhaps it could have been one of the assisting factors. There are those possible cold joints that SFCharlie pointed out. Would be amazing if we actually know which column that was and to which floor the photographed section belonged to.


@Arbitraria
Original doors. They were good, solid doors. Faux coverings were on the some of the interior of some doors.



Edit: I just want to point out that that almost all of the approved rebar placement on the original construction and for renovations/repair work called for a minimum of 0.75" of spacing between rebar.
If 1" was the code minimum spacing, I have two questions.
1) How did this get past everyone?
2) Why was this spacing allowed to continue on work through to permits as recent as 2010?

This whole mention of not enough bar spacing in the columns is interesting. Unless they used 3/8" aggregate grain max on original construction, I'd suspect there to be a lot of voids in the concrete where water could collect and do it's magic work as the best universal solvent we know. That could even help hide full sections of rusted out bar as there'd be minimal to no spalling in those locations until it's too late.

 

[AutisticBez]

UPH. So, to me this feels like a low density low weight occupancy. Like a standard floor would have a lot more weight to it. To me the floor is open plan, less walls. The sides are also open. To me it doesn't feel like a big deal. Then again how many pancake collapses occurred due to floors added onto the design later?

The thing is, its not like the roof had massive HVAC on it like that Korean mall collapse. But certainly this side of the building has smaller columns then the surviving. Plus those beams connecting the pool deck.

But what pisses me off is the complete lack of security footage from the building, surrounding buildings, traffic intersections, the beach walks, the lane walk. Where is the footage? How do we literally have nothing? Nobody got any other angles? The hell man, this is some BS. Half the debates had in 11 threads would be resolved if just a video or two came out.

 

[gonefishing2]

@‘NEW’ SFCharlie,

Just gotta ask! How is an ‘Old’ SF Charlie reborn as a ‘New’ SF Charlie on this Forum?

Point being, I need some of that special elixr!

 

[gonefishing2]

Not disagreeing with Santos81 about pre-planned Penthouse based upon his observations, but it sure seems to be a real mess getting there. I have attached just one of Rodface’s sorted document packages, this one titled Structural 14 pages, and I will be first to admit, I may miss a lot looking at these PDF’s on a laptop, and not having the ability to print them out full size to really analyze well.

1 Please note page S12 shows elevator section view for a 12 story building and not have extended height middle section to allow UPH corridor tie in to main elevator shafts.

2 Then notice one of the S13 Beam Schedule ends at Beam 35 and another S13 goes to BM42 (which adds UPH and roof beams, as I remember)

3 Then S14A shows UPH, Corridor, and Elevator Section that has added vertical section to accommodate UPH. Typically you don’t add A revisions unless something has changed. Of course again, this could be way to play the game spoofing the building department or the local politics.

I think I saw several UPH designs as far as whether it has it’s own dedicated elevator or the long corridor that connects to the main elevators.

To me it sure looks like this was a 12 story building design originally, then a lot of under the table and trades were going on to try to find a way to scab a UPH cheaply onto 12 story design, and NOT that it was designed originally for UPH originally.

I also wonder why, if you are doing the UPH for more bang for buck money, why did they not just have a full 13 story building with say 2 or 3 UPH units? Perhaps not enough money for full 13 stories or there was some concern or too costly to scab on a full 13th floor? Perhaps wind loading or some sort of loading issues?

It also seems odd that they would stick UPH on the skinny column section, and not the beefy column sections, unless it was going to cut down on parking spaces and they needed more spaces?

Does the larger garage columns have anything to do with the transfer beams in the lobby area and the eccentric loading of those columns or the floor to height spans of those columns required beefier column to resist buckling?

Bottom line thinking to me, was the original Architectural Plan was for a 12 story building, but perhaps the developer was driving the train to scab on the UPH from early on, just had to release that scab at correct time?

 

[Debirlfan]

It also seems odd that they would stick UPH on the skinny column section, and not the beefy column sections, unless it was going to cut down on parking spaces and they needed more spaces?

Two words. Ocean view.

One other comment regarding the 904 survivor's statement. Note that was relayed thru a 3rd party, and may not be totally accurate. It's possible that stepped out the door COULD have meant the bedroom door, rather than the unit door.

 

[arbitraria]

@Demented - I looked at the condo association's letter to the owners from April 9 of this year, their balance sheet had a special assessment from 2016 for unit doors in the amount of $252,000 - guessing that hadn't happened yet as the money still appeared to be in their reserves.

They also mention the association having as-builts on file, I wonder if there really was a set floating around out there like a mythical unicorn, or some sort of holy grail...more likely they cobbled together a set of plans over the years as they had repairs and upgrades done, then referred to those as such.

@AutisticBez - I believe Santos81 confirmed that investigators are in possession of better-quality (than what the public has seen) video from several angles, and I'm sure they have more than what he's mentioned. Anything with better resolution is going to show some pretty awful details, given that people were out on their balconies...understandable that they wouldn't release those to the general public. I don't know what the protocol is as far as this being a crime scene but I'm sure that factors in as well.

@AllAboutMoney - I think the location of the additional penthouse had almost nothing to do with the structure itself, far more to do with proximity to the ocean. Better views cost money, stands to reason they'd put the most expensive unit in the building in a spot that would justify charging even more for it.

 

[SFCharlie]

@‘NEW’ SFCharlie,

No magic here
At the top of this page find:
Home>>Forums>>Engineering Forums by Industry>>Forensic Engineering>>Engineering Failures & Disasters Forum
click on "Failures & Disasters"
Scroll down to just under the ad
click on Start New Thread
Name the Thread
Post with links to previous threads with names
click Submit Post
Standback

Is this what you were asking?

I have a text file with all the previous threads and link
Oh Now you have a link to the new thread, go back and post a message in the old thread.


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[Reverse_Bias]

Another thing that never mad sense was the the thicker columns on the western side to hurricane proof the building. Wouldn't you want to hurricane proof the entire building?

 

[SFCharlie]

... thicker columns ...

The article I posted blamed the thicker columns on the valet parking ... Link


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[gonefishing2]

@SFCharlie, Thanks for responding. So New label means new member or new thread? Just curious?
I forgot about the Valet Parking Comment, thus I get the reason now! And duh, I get UPH was ‘All About Money’ and squeezing in one grand UPH Ocean View for Big Bucks!

 

[zebraso]

thicker columns on the western side to hurricane proof the building

That makes too much sense. Any thought about prevailing offshore winds at landfall in this? Where would the shear accumulate?

 

[SFCharlie]

New label means new member or new thread

new thread
I'm the same old SFCharlie as far as I know...

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[SFCharlie]

duh, I get UPH was ‘All About Money’ and squeezing in one grand UPH Ocean View for Big Bucks!

"The want of money is the root of all evil" ... the money's not evil, the want is...

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[SFCharlie]

Maybe not exactly on CTS, but shows that there are consequences:
Miami apartment building deemed unsafe, residents forced to evacuate

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[Santos81]

why did they not just have a full 13 story building with say 2 or 3 UPH units?

Very simple.

13 residential floors in a 12 floor
/120’ Zoning District would have been automatically rejected.

 

[SFCharlie]

This snuck under my radar:
Emergency Works Taking Place This Weekend At Champlain Towers South Site


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[SFCharlie]

More digging:
Champlain Towers South Site in Surfside Heads Toward Sale
Site of collapsed Surfside condo listed for sale


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[SFCharlie]

Interesting and describes data collected before and after demolition:
Meet Surfside's Disaster-Data Forensic Sleuths


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