Miami Beach, Champlain Towers South apartment building collapse, Part 17 14

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 14
Miami Beach, Champlain Towers South apartment building collapse, Part 15
Miami Beach, Champlain Towers South apartment building collapse, Part 16


SF Charlie
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[Sym P. le]

An isolated zone of sprinkler piping back draining is the most logical explanation to me. What would a drain pipe be draining?

Edit: Although sprinkler system back flow could be rather discolored, not appearing so white.

 

[MaudSTL]

That suggests the lobby parking area went first, followed by the pool deck.

I certainly agree, because that’s always been my theory. But I’m an analyst so my opinion doesn’t count. Let’s see what everyone else says.

>>>>>Edit: one thing you learn when you fly in hot air balloons is how well sound travels upward. This couple was perfectly positioned above the action, so the metallic crunch, which is higher frequency than the crashing, would have traveled to them very clearly. I doubt there was any significant delay between the car park collapse and the wave from the south, just based on my understanding of punching shear failures.<<<<<

 

[Sym P. le]

A quick study suggests it would be generous to say they had a complete view of even the pool deck.

Edit: full scale attached below It won't attach with edit

 

[Nukeman948]

Thanks for your response, it cleared up some things for me.
The lobby would have a pull station at each exit, one at the front door, one at the exit to the pool area, and one at the service ramp on the north side.
Most pull stations just have a simple toggle switch, either on or off. This was an addressable system so all initiating devices like pull stations and smoke detectors would also have a small electronic module to identify the device at the control panel. The panel polls the devices to check their status. Either activated or not activated. If the panel does not get a response from a device it logs a trouble code for that device. So if it was not working it should show up in the fire alarm log.

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[MaudSTL]

@Nukeman948, so we are saying there would be no pull switch at the security desk? As a civilian, that surprises me because I would have imagined the security desk would have all the controls.

 

[MaudSTL]

@Sym P. le, I would have thought they could have a wider view from that vantage point.

 

[Nukeman948]

An isolated zone of sprinkler piping back draining is the most logical explanation to me.

Why would the sprinkler system be isolated?
Why wouldn't it flow from both directions if it was a sprinkler pipe?
It could have been a domestic water supply pipe. I don't know and it doesn't matter.
None of this has anything to do with the original point I was making that there may not have been flow in the sprinkler pipes, but Maud's post that came after mine seems to have cleared that up.

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[Sym P. le]

I would have thought they could have a wider view from that vantage point.

Likewise, until I sketched it out. The edge of the balcony creates a greater obstruction for someone standing inside the unit than I thought.

Had they moved out onto the balcony, they would have had a much better vantage point however it doesn't seem like time was available for that to happen and in their minds, they had all the information they needed to tell them to get out.

Edit: Perhaps the take away is that they could see enough of the pool deck to see what was going on but they couldn't see the parking area directly beneath them unless they moved out onto the balcony.

 

[Nukeman948]

so we are saying there would be no pull switch at the security desk?

The security desk is where the fire alarm annunciator panel was and it has a switch built in so there is no need for a separate switch. It would also have lights or a read out to show which zone had an alarm activation and the address of the device.
It is also where the "all call switch" was located along with the microphone to give voice directions to evacuate.

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[Sym P. le]

Is the punchout pattern around column 72/73 indicative of a directional wave of failure? i.e. The typical wedge of concrete on the south and west sides of the slab/column connection may indicate a zone where typical bending failure occurred while a wave of failure spreading to the northeast caused the slab to shear off the column vertically on the north and east sides.

Edit: ... which may bring us back to the big heavy truck parked southwest of that column.

 

[Sym P. le]

It could have been a domestic water supply pipe.

Yes. Now you're making sense. Backflow of domestic water?

 

[Reverse_Bias]

Likewise, until I sketched it out. The edge of the balcony creates a greater obstruction for someone standing inside the unit than I thought.

Remember the deck started 6ft higher up.
Hindsight 20/20 if they had walked on the balcony with their phones and shot a 20 second video of the deck and the edge of the building before it collapsed we might know the cause of the collapse.

 

[Sym P. le]

If the security cameras were on around the pool deck, we would have more answers as well. Maybe they were and the investigators already have the info. I can't imagine turning on my phone cam that fast myself.

 

[Sym P. le]

Longobardi's potential view to the south is much more directly down so I've indicated a potential footprint of view accordingly.

 

[MaudSTL]

I am trying to visualize how this would work. So if the planter/parking deck fell with the sound of thunder, are you saying that could have pulled the deck off the south wall and resulted in the south-to-north wave?

 

[Sym P. le]

I was just trying to gain some appreciation for the witnesses proximity and vantage point. It would seem the Longobardi's are the best witnesses to date and that gives a lot of weight to their statements. At the end of the day, all of the evidence should be telling the same story. As "investigators" we are the ones who have to challenge our thoughts and preconceptions to figure out what that story is.

 

[FJBnomics]

IanCA, who are these people???

 

[IanCA]

IanCA, who are these people???

It is difficult to tell at times. I think they may be using pseudonyms.

 

[FJBnomics]

No matter who the pseudonyms are, please carry on!!!

 

[SFCharlie]

IanCA, who are these people???

If you are referring to the people in the NewYorkTimes article, they are Anastasiya | Paolo Longobardi. At least one major network has confused them with another family of four, but a google picture search will reveal:

It was like a wave coming from the right to the left… from the south to the north
The loud noise that brought Jonah and Ms. Fang to their balcony in the initial stages of the disaster also awakened Paolo Longobardi on the third floor. Thunder, he thought. But his wife, Anastasiya, had heard something more unsettling: an unnatural, metallic crunch.
The two of them, groggy with sleep, peered out the sliding glass door of their bedroom overlooking the pool. Below them, the pool deck was caving in.
“It was disappearing into the ground,” Mr. Longobardi said. “It was like a wave coming from the right to the left — from the south to the north — and it was falling.”
As he watched the pool deck collapse from Unit 309, Mr. Longobardi, a civil engineer who builds bridges for a living, thought a huge sinkhole might be swallowing the parking garage beneath the deck.
“We decided to run,” he said.
The Longobardis woke up their two children, ages 14 and 9, and ushered them out the door. Mr. Longobardi said one of the children recalled hearing an alarm during the escape.