Miami Beach, Champlain Towers South apartment building collapse, Part 05 111

[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


SF Charlie
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[Murph 9000]

MarkBoB2, keep in mind that there was no real "accumulation" of A/C condensers on the roof, as suggested in some theories. They had all been there for 40 years, and were present in the original 1979 plans in the same basic locations. Most will have been replaced over the years, like for like, but the general structural load shouldn't have changed much. The only way they are really a major factor is if the penthouse roof was critically weak.

It was the big HVAC for the common areas, on the red frame spanning E2–H2 and E4–H4 that changed more notably. It also shouldn't have been a major factor, being directly mounted on 4 columns, and not anywhere near the initial collapse. E2 and E4 survived to the end, defiantly poking out of the top of the controlled demolition, as the building dropped slightly ahead of them. They changed it from two separate units to a combined unit, so overall weight should have been in the same ballpark.

 

[SFCharlie]

How many units were there? It looks like the last ones sold went for about $700K. What was the square foot each floor?

Here is some recent info
_ _ _ _ _ _ _Studios _ _ _ 1 Bedrooms _ _ _2 Bedrooms _ _ _3 Bedrooms _ _ 4+ Bedrooms
Total: 342 _ _ _0 _ _ _ _ _ _ _ 54 _ _ _ _ _ _ _219 _ _ _ _ _ _ 66 _ _ _ _ _ _ _3

SF Charlie
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[Spartan5]

Spartan 5, you have a concrete and masonry parapet wall surrounding roof, that is around 42" high to deflect wind from blowing outdoor units around

In a Category Anything storm making landfall right at the building?

Is that your guess or are you telling me that the code makes no requirements for the secure mounting of mechanical equipment on the roof in high-velocity hurricane zones because a 3-1/2’ knee wall will keep them from blowing around in 100+ MPH sustained winds? You can’t see it but I’m making my skeptical face. If that’s the case, it will be the most shocking thing I’ve learned today.

 

[jbourne8]

I find it really hard to believe that Cassondra in 412 saw bits of the roof falling down and then called up her husband to say the pool deck was collapsing and she thought it was a sinkhole. I kind of bet the damage to the pool deck wasn't nearly as wide spread when she made the call, or there's no way she wouldn't have just run for the exits. I think more than anything, the lack of survivors really shows how much the building stayed mostly together until those last seconds.

 

[julootamu]

As I posted earlier, I'm an HVAC/ Energy conservation engineer. These units are required to be bolted down. I've installed several units myself, even in the early 1980s. Every heat pump/air conditioner I've ever seen has factory holes at the bottom of the units for mounting. Some are easily accessible and the instructions that come with the units say to mount them. The ones I installed were attached to steel concrete anchors embedded at least 3" into concrete slabs. I can't say if an installer skipped this step but an inspector should check.I've installed York, Carrier, Trane, and Mitsubishi and all had sturdy mounting holes and tabs at the AC unit's base.

 

[julootamu]

There are factory holes at the bottom of the units often offset so you can get to them and bolt them down without throwing a strap over the top of the AC unit. Even in the early 80s.

 

[julootamu]

All, even composite have to be designed for mounting even at your house. And on the tall Mitsubishi I put in the unit had heavy duty tabs with a hole in it that extended 3" from unit for easy installation. No regulatory bdy would accept loose units not bolted down. Not inland either due to wind or tornados.

 

[zebraso]

I never said anything about what the code says.

I know my unit residential at ground level is not tied down in any fashion. That's beside the point. What are the odds that one unit out of how many on that roof had a degraded or corroded attachment that broke loose considering the claims of neglect elsewhere?? I get your point though. Also it was somehow inferred that the sheer weight of the units played a roll (not by you). I think the weight distribution in the unit was only pointed out to state how easily these would roll or topple if they broke loose. The fact of where it may have ended up is symptomatic or some prior event taking place and nothing more. I think.

 

[julootamu]

If you have a residential unit not tied down you had a jack leg installer. The three I've had at my house were all fastened to the 4 x 4 ft concrete slab first put in for that purpose. Codes if you have any specify it. Guess I have to dowload a Rheem manual. Simply crazy to think you don't bolt it down.

 

[jbourne8]

There's a new interview from the woman in 506:

https://www.youtube.com/watch?v=5Tg_Z0sSNg4

Sounds like she heard a thunder noise and saw dust before the building collapsed.. or perhaps that was just the first part of the collapse.

 

[Spartan5]

What are the odds that one unit out of how many on that roof had a degraded or corroded attachment that broke loose considering the claims of neglect elsewhere??

Slim? Considering the building just had a comprehensive 40-year inspection by a licensed SE/SI.

Even in the fringe theory outlined above the inset picture shows that the units were mounted to a rigid frame of some sort above the roof surface.

 

[CE3527]

The roof first collapse theories don't really line up with the following:
1) eyewitness accounts that the pool deck collapsed first, they called it a "sinkhole"
2) the punch through failure of the column/pool deck connections at the the columns. If the building fell first on the pool deck, you'd expect to see shear failure at the impact area instead of widespread "settlement" of the entire deck and several columns that demonstrated punch through.
3) the collapse video shows the face of the building collapsing as one piece, suggesting a failure at the foundation. With a top down failure at the roof, you would see pancaking of the top cascading down to the bottom.

 

[julootamu]

No telling what happened at Champlain. Due to increases in efficiency in new units and becase R22 refrigerent used even 20 years ago in new unitw, these units have probably been replaced at least twice since the early 80s. Maybe the installer didn't bolt down but should have in a hurricane prone area. Sure its req'd in Miami. I had a tall Carrier installed at my house that didn't have offset tabs that reqd taking the grill off the top to bolt it down and using a long drill bit to put new holes in the slab to install new anchors. Still had factory supplied holes for mounting. Didn't mean to go off on a tangent.

 

[dik]

Amazing how fast the authorities act when it affects their livlihood...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[gonefishing2]

I sure don't know how things work in Miami or in condo;'s, but I would think each unit's HVAC system is the responsibility of each Condo owner, since it is not part of the common property, with the exception of the common area unit. That being said, each unit owner is hiring the jack leg to do their replacement units, I would think

 

[OH_PE]

you had a jack leg installer

Well, the previous owners had the jack leg installer- but mine was not bolted down.

Wind or not- they should be bolted down simply so the lineset is not a main component of the provider of force reacting against the start up torque of the fan motor.

 

[Demented]

I guess you all have never seen contractors in the Miami area glue/epoxy cut off bolt heads onto things.
Calling the quality of Miami area installers jack legs is an insult to jack legs.

You know the ol' saying. Tighten her until she starts to loosen, then back it off a quarter.

 

[waross]

There may be more reaction torque from a vertically aligned compressor. It is often many times the HP of the fan.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Sym P. le]

MarkBoB2[/b] (Electrical) 10 Jul 21 18:41]

Great work!

The following images compare the TikTok view to that of the Champlain North tower from Google Earth. It seems that the column between stalls 27 and 28 has been obliterated and perhaps the rebar from the column lays across the entrance aisle. The column at front of 28 (next in line in these images) is known to still be standing having punched through the slab and being visible in the post collapse imagery.

The missing column would be unique in not having punched through and this would be consistent with impact from falling debris. MarkBoB2's comparisons are compelling even if hard to believe.

In the following, I've scrunched the image width to somewhat account for the difference in perspective.

 

[Spartan5]

The unsecured residential cooling unit rolled through a parapet wall… free-fell 12 stories before slamming into the concrete slab below… and is still recognizable. I’m amazed by that too.