Miami Beach, Champlain Towers South apartment building collapse, Part 14 41

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 11
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13

SF Charlie
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[SwinnyGG]

The column planting itself there theory doesn't work for me.

This is where I'm at on this particular issue as well.

Although no reasonable explanation makes itself evident. It's pretty damn weird.

 

[Debirlfan]

Looking closely at the photo zebraso posted, it almost appears there is a dark colored square at the base of the protruding rebar. The rebar is also discolored (dark) just above the water.

Is there any conceivable possibility that the pieces of rebar might be welded to a steel plate which is now at/under the surface of the puddle? Perhaps something that fell from some floors above?

Given the state of repairs on the building, it seems easier to believe that someone tried some sort of jury rigged patch than that either the rebar managed to impale itself in the slab, or that a column appearing in the middle of a drive lane was never commented on.

 

[Jeff Ostroff]

I know a few people have mentioned that the rebar coming out of the floor of that mystery column appears to be an area that was patched up. Although I don't see how people can see that through the water that's at the bottom. And I think a lot of these lines that are tricking people's minds into seeing patch lines are really just reflections of all of the rebar coming up out of the ground reflecting from the water.

The reason I don't really accept the fact that the K column could have impaled into the concrete, is that there should be a lot of floor damage would have happened, cracks in the concrete floor or craters or something but not just perfect perfect rebar rods going into the ground.

I still think the only scenario that fits the whole bit of Current evidence that I showed in my video, is that sometime between July 2020, and the time of the collapse somebody built a column there,

It wasn't to support the H-beam because it is too far away from the H beams 2_3 FEET so likely it was there to support the garage ceiling next to the H-beam. Why they would have done it? Who knows. Handyman special maybe? I searched the Surfside website and found no permits for it in the last 24 months. I think handyman special because there are no piles below it to support it So it might have just been a quick fixe type of thing. Temporary shoring.

 

[SwinnyGG]

Temporary shoring

That's the thing... pouring a column would be a very expensive, time consuming, and extremely labor intensive method of providing temporary shoring. Not to mention that it would be highly ineffective.

I know there's idiots out there but someone doing something that stupid is, for me, a bridge too far.

From all the photos and video, it seems pretty clear that the location of the H beam, surrounding columns, ramp edge, etc are at this point pretty clearly known to the group, so I don't see how this could be a case of ALL of us mis-identifying something.

If the column punching from above theory was correct, that also would not explain the missing slab section (ie if this column punched through from above, where is the little square of slab that punched out, along with its horizonal bar?) which would in theory be underneath that column, between it and the deck it impacted.

There's also the fact that the lengths of that bar seem to indicate the top of a column - not the bottom. Unless this bundle of rebar was much taller at one point and was cut during demolition. I'm not sure if we know either way at this point.

My hope is that at some point NIST or whomever will address the presence of that mysterious bundle of bar. But I'm not optimistic that they will.

 

[SFCharlie]

Got it!

SF Charlie
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[Optical98]

Omgs *snerks*

 

[Demented]

@Debirlfan
Unlikely it's rebar welded to a plate. If it's gotten that black from welding heat, I wouldn't expect a weldment like that to survive with rebar still attached to a plate.

I'm on the fence about a column punching through as well. It's rather odd, especially since it appears to only be in one location. The lack of blue or red markings on it also compounds to my confusion.
@Swinny, there are other column bases with similar lengths of rebar on the basement level, so it may not necessarily be a top of a column.

Kilsheimer and crew have more photos of the slab. The ones we've been privileged to see are just some quick iPhone 11 photos taken rapidly as they marched around the site in about 50 minutes.

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

 

[SwinnyGG]

there are other column bases with similar lengths of rebar on the basement level, so it may not necessarily be a top of a column.

Now that you mention it...

I was previously just looking at the closeup. Looking at other pics where other former column bases are visible, the length of the rebar in the mystery column does appear to be in a similar range as the ones nearby.

In the closeup I was thinking it looked like the rebar left sticking out of the slab was way too long to be the lab bars which would extend through the joint with the slab.. but that was a minor error on my part.

 

[Red Corona]

All those sticky up lengths of rebar are at the length the demo team cut them off at, I think.

 

[Nukeman948]

... pouring a column would be a very expensive, time consuming, and extremely labor intensive method of providing temporary shoring. Not to mention that it would be highly ineffective.

I know there's idiots out there but someone doing something that stupid is, for me, a bridge too far.

I agree with all those points 100%.

We can also probably agree that Florida does have some of the worlds stupidest handymen to even suggest putting the worlds stupidest column in the the worlds stupidest location for the worlds stupidest reason, whatever that may have been.

However, Florida is also home to some of the tightest skinflints that ever pinched a penny and they are all sitting on those condo boards clutching their purse strings with an unmatched death grip. Somebody would have had to approve of this before it happened. To my way of thinking, the bridge too far is believing anyone would approve of such an ill conceived idea as a useless "mystery column in the driveway" and then be willing to pay cash so there would be no paper trail. That bridge too far was a wooden bridge that has been soaking in kerosene for 100 years in a location that has more lightening strikes than anywhere else in the world. It's "unmatched" if you will.

This horse is dead.
Beat it.

Sig lines are for trolls.

 

[JR97]

Is the mystery column visible in the garage walkthrough video from 2020? I get so twisted around I can't tell.

 

[SFCharlie]

Is the mystery column visible in the garage walkthrough video from 2020? I get so twisted around I can't tell.

It is visibly not there.
See:
Champlain Tower South: visiting unit 611 on July 17, 2020 - Surfside FL condo collapse
at 5:05 (you will have to pause or type "k" as soon as it turns to the end of the building, or the video will end.)
edits in italics.

 

[SFCharlie]

Nukum948's well-thought-out post is correct.
When someone publicly miss-represents their credentials, I feel it is necessary to point it out.

Several of you have questioned the plausibility of the column impaling itself in the slab.
I would like to draw an analogy to a piece of straw or a 2 by 4 impaling itself in a palm tree while leaving the tree intact. This seems implausible, but has happened during a hurricane. Yes, there was no hurricane, but the energy of a thirteen-story-high column, driven down one story without support, by gravity, would be very high. The column may have driven itself intact into the slab, but then disintegrated or have been demoed by excavator after that, leaving only the rebar above the slab.
I have no idea how or why the "H" beams left the column unsupported.
edit in italics

 

[Spartan5]

I’m the farthest thing from an expert on these matters. I mean, I don’t even have my own YouTube channel FFS. But assuming we needed temporary shoring in a place that doesn’t make any sense, why a concrete column.

Again, not a licensed structural engineer here, but I imagine it would have involved the following steps (in any order):

Saw cutting and removing the existing slab concrete top and bottom.

Drilling horizontal holes in each of the slab to receive/tie epoxied rebar for continuity (the very stuff we see sticking out of the slab now; many pieces).

Forming the new column which would have to flush with the slabs top and bottom.

Injecting concrete into the form from the bottom with a relief tube at the top until you see a return of the pumped concrete. And I guess vibrating the whole thing to boot given how tight that rebar is?

All of that vs. a steel I-beam with a couple of flanges on either end that gets bolted/anchor in place.

Am out out in left field here? Or in the parking lot even?

 

[SwinnyGG]

@Spartan:

It's even worse than that.

Concrete shrinks. For it to be of any real use as shoring, you'd need to cast the column in place without providing a tension tie to the slab above. You would need to either use smooth dowels into the upper slab with bond breaker on them, or you'd have to just not put any rebar in the upper slab at all- meaning you'd have zero shear resistance at the joint, which means the value of the column as a shoring element is severely compromised.

Then, after the complicated and expensive casting of this column, you'd need to leave a space between the top of the ghost column and the slab. You'd need to wait quite some time - at least a month, potentially longer - for the concrete to be sufficiently cured that shrinkage has stopped; you'd then pack the space between the top of the ghost column and the slab with non-shrink grout.

While you were doing all of this, if some kind of beam failure or collapse was the concern, you'd need to put conventional steel jack shoring in place to protect the beam during the 3 months it would take to install the concrete column, wait for it to cure, pack with grout, and wait for THAT to cure sufficiently to handle major load.

 

[SwinnyGG]

The column may have driven itself intact into the slab, but then disintegrated or have been demoed by excavator after that, leaving only the rebar above the slab.

I still contend that if this is what happened - the column above punched through the slab and impaled itself into the lowest level - there would be clear indications which are not present.

That column was not floating in air; it was sitting on the next level of the deck. In order for it to punch through, it would have to punch out a little rectangle of that deck. While that type of failure is possible- and in fact is seen elsewhere in the collapse- it would be obvious because the horizontal rebar in the punched-out section would be visible. Below that bundle of rebar, there would be at least a couple of horizontal bars trapped. There aren't.

The only way this would not happen is if, as the column punched through the slab, it punched out an exactly perfect rectangle which exactly matched the outer dimensions of the column, and perfectly sheared off all the horizontal bar. Then as the bottom of the column hit the lower slab, it would have to penetrate deep enough to push that little rectangle of upper slab completely below the surface of the lower slab. All without leaving any surface cracking whatsoever (at least as far as we can tell from the photos we have) evident on the top surface of the lower slab.

I contend that this is not impossible- but the probability of such a 'perfect' scenario is microscopically low.

 

[Spartan5]

The remnants of whatever column came through the floor above would have been traveling 20 mph with the weight of a portion of plenty of building behind it when it hit something solid again. Meaning it would inclined to continue moving that fast.

Could that effectively punch clean through the slab in the garage, shearing anything off that came with it? And if it could, wouldn’t most of the carnage be on the back side of the slab (AKA the exit wound)?

 

[SFCharlie]

I have been slow to figure this all out, but my present understanding is that the column was supported by the "H" of beams, but that the column was not directly tied to the beams, rather, the first floor slab was attached to the beams below it, and the column was attached to the first floor slab. How and why the "H" moved enough northwest to slide off the four columns that supported it, is beyond my understanding, but the evidence is that this happened. The "H" dropped from the top of the garage to the bottom. the remnants of the 1st floor slab have apparently been removed. all that is left is the rebar sticking out of the garage floor slab?

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[SwinnyGG]

the remnants of the 1st floor slab have apparently been removed. all that is left is the rebar sticking out of the garage floor slab?

What I'm saying is that that column had 1st floor slab underneath it; if it punched through, there would be horizontal bar in that bundle.

Unless for some strange reason, during demolition, they removed any horizontal bar. But why would they do that and leave the vertical bar bundle there? Makes no sense to me, but maybe they did.

And if it could, wouldn’t most of the carnage be on the back side of the slab (AKA the exit wound)?

Two points on that line of thinking - one, perhaps the damage would be worse on the back side; but there would still be damage on the front and there is basically none at all, which makes no sense; second, there is no 'exit'... below that first floor slab is dirt. The compressive strength of dirt is not infinite, but all of these elements are incompressible (the dirt, the concrete, the rebar, etc) which means any punching through of the basement slab would mean displaced volume that has to go somewhere. My guess is it would swell horizontally and cause additional cracking in the basement slab, which again appears to be perfectly uncracked. Again just conjecture on my part... I just can't wrap my head around what we're looking at here.

How and why the "H" moved enough northwest to slide off the four columns that supported it, is beyond my understanding, but the evidence is that this happened.

The 'H' undoubtedly moved horizontally during its fall, no disagreement there. But the location of that bundle suggests that the column above would have had to come perfectly straight down. My issue with that is that the 'H' was attached to the first floor slab, and the column was also attached to the first floor slab. So how does the 'H' displace laterally BUT the first floor slab stays exactly where it is, and the column comes down exactly vertical? Seems unlikely to me.

 

[Nukeman948]

... as the column punched through the slab, it punched out an exactly perfect rectangle which exactly matched the outer dimensions of the column...

My thought was that if the "K" column broke off from its supporting beam, most of the concrete at the bottom would be crumbled leaving 6 to 12 inches of rebar sticking out. A concrete nail doesn't need to penetrate all the way through a slab to hold tight and the rebar, acting like a concrete nail, wouldn't need to penetrate all the way through to remain in place. This would improve the probability.

Edit: I now see what you are saying about the horizontal bars but they may have remained on top of the slab and been loose enough to get removed in cleanup.



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