Miami Beach, Champlain Towers South apartment building collapse, Part 09 139

[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

SF Charlie
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[SFCharlie]

The city has withheld any known directly relevant documents to the collapse I believe. Items I've asked for they have not been able to provide.

Yes, and I notice they have successfully prevented most drone video except for the fire department's from being published.
They also hindered the residents of adjacent buildings coming and going.
Also, except for Because Surfside no one seems to have published video from adjacent balconies.
And, all their live videos have been deleted.
"respect for the victims' families"?



SF Charlie
Eng-Tips.com Forum Policies

 

[Demented]

I would argue the new folks went to the trouble of joining and posting here because they felt something was missing as far as theories or stringing together the chain of events that led to this disaster.

It would be great to find out it was something really simple and easy to fix so this would never happen again, but after 4 weeks or so of posts, I do not feel that will be the case. Folks have done an amazing job at identifying key vulnerabilities in the structure and provided analysis to explain the weaknesses.

The public has been blacked out of key and validating information due to so called 'crime scene status', thus this is going to probably play out for years in our court systems.

Even Building Integrity's last video post was lacking to me in content. Perhaps we are at the end of the road without sufficient validated data to crank into our models. Also it has been said that there is so much of this building that was not OEM, that it will in all likely hood, be very hard to build those models. Especially after they demolished the key remaining in tack evidence. Look at what appears to be large variations of quality of construction, latent defects or defective maintenance repair work. The materials testing will help get a feel for the general quality perhaps.

Here is a link to Building Integrity's explanation of shear walls. I had hoped he was going to get into the fact that the columns sure looked beefier in the part of the building that was still standing versus the area that had the PH. Why does there appear to be key structural robustness differences in the two parts of the buildings? That is of interest to me, and the effects of such. E.g. The elevated parking fell without taking down the building above it.... It is almost like they built up to the shear wall, then added on beyond the shear wall, but that makes no practical sense. Or designer started designing the remaining part first, but then got pressure from developer to lower costs, so margins were taken out of rest of building, but left in original to save re-design costs? Far fetched but the why the difference is very interesting..

https://www.youtube.com/watch?v=2DmPcIzsQtM

I'm nearing on impossible. Much of the building turned to powder when it fell (as it seems most of what was put back was epoxy and mortar, not cement), so even material testing wont show us a clear picture of what was actually where.


Could the design differences be to have kept the BOM the same, but still build the penthouse additions? Length of rebar, volume of cement, and pallets of CMU. That could easily satisfy a client with very minimal effort in design change. Were the pile changes around the same time as the column and dimension revisions? I never saw the original geotechnical report that made them switch so close to initial construction.


@SFCharlie
The police were attempting to shut him down for weeks. Within hours of MDPD taking over control of the site, all of his streams and nest cams went down. Not sure why but they really were not happy with him.

 

[Optical98]

SF Charlie,
The Because Surfside videos were frustrating, because you couldn't see the most pertinent areas, but you could see clearly several times, people recording from 87th Terrace. And yeah the chat was juvenile.

As I posted several threads ago, any pictures or video of the front of the building (after June 24th) are impossible to find.
And when I say front, I mean the lower drive thru area that we know had damage.

 

[Optical98]

Demented,

Do you know what was the MDPD's stance on the demolition of the west end? The way they have taken over the scene, labeled it a crime scene and wouldn't let AK on the scene to test anything....
Makes me think they weren't happy about it?

 

[gonefishing2]

In my City, Mayor’s Control Police Chief’s. Our DA actually open a can on corruption by City concerning coverup. Did not fully expose everything due to missing information, but did charge criminal actor, and it resulted in conviction by jury.
And Mayor’s are controlled by their funding sources.

 

[Optical98]

Thermopile,

When Cavo signed off on the ordered to demo, she stated that it would still take 2-4 weeks before all was planned and executed. But like whiplash, it was being prepped for demo a few days later.

And well, even if MDPD answers to Cavo....doesn't mean they agreed with this decision... they're calling it a crime scene for a reason.

 

[gonefishing2]

Optical98, What is confusing to me is why each City with a Mayor, does not have there own PD. That is typically what I see in Inc towns. Out in the Counties the Sheriff’s typically are primary. How does all this work in Miami-Dade?

Does Surfside have their own Police Force? I can see making this a criminal investigation could be because of a deliberate or stupid act was trigger, but I can also see it is to protect Miami’s Condo Money Printing operation, and perhaps somewhat to keep folks calm and not thinking ever old Condo is at risk. If folks are scared away from Condo’s on Reclaimed Ocean, what happens to South Florida’s lively hood?

And then this could be an opportunity to condemn old Condo’s on prime real estate, so Developer’s can start urban renewal again to create new fatter profits?

 

[MarkBoB2]

The photo of a PVC pipe with trap shown by Demented in section 08 and discussed further by Thermopile and Optical98 was really interesting because it shows that when they want to zoom in on an object in a video taken from a drone flying overhead, then they can see a 2 inch diameter object clearly enough to distinguish whether it’s a pipe or an electrical cable. Yet, they can’t see another zoomed object that is 36x36 inches square in another video.

This photo also intrigued me because of its high resolution. Not seeing Demented’s reference to the video until later, I tried to find a similar photo with the same high resolution and came up with one taken from a different perspective. And when I zoomed in on the green tarp behind the air conditioning units seen in Demented’s photo, look what I found:

It shows a green tarp covering rolls of tarpaper (aka roofing felt) on a wooden base. The rolls are almost all standing on end and there are 7 rolls in each direction, giving 49 rolls on the wooden base. On top of the rolls there is also a metal object of some sort. Since rolls of tarpaper are always 3 feet wide and one of the rolls is lying on its side, it is easy to verify that the wooden base is 6x6 feet. Depending on the thickness of the tarpaper, one roll can weigh between 35 and 85 pounds. Assuming 50 pounds per roll to be on the low side, this gives about 49x50 lbs = 2450 pounds plus the weight of the wooden base and the metal object, or about 2500 pounds, or over one ton. This corresponds to about 2500/36 ft[sup]2[/sup] = about 70 lbs/ft[sup]2[/sup]. This is a heavy load on the roof of the 12th floor of the building that was still standing. If the same load was later placed on the penthouse roof with its thinner slab, then it seems like it might overload the penthouse roof and cause it to collapse. I’ll leave it for someone else to determine the maximum load for the penthouse roof and what the margin might be for collapse.

It just occurred to me that the Surfside building inspector was on the roof just the day before the collapse. Do you think he saw this high concentration of tarpaper in one area? Also, we have not seen any rolls of tarpaper on the debris pile anywhere. So, perhaps there was no similar green bag with tarpaper on the penthouse roof.

 

[MechinNC]

I like the point Building Integrity made about the fracture in the core samples showing that the layers of the patio slab had delaminated. Basically it meant that the punch through shear forces were being resisted by much less steel than if the delam had not occurred.

 

[MaudSTL]

This platform makes it difficult to look at gathered evidence (or lacking) of a theory/hypothesis in one place..
Perhaps a spreadsheet would be helpful. How would it be made available for us to examine? Also it can't be up to one person to determine whether evidence gets added or not... Proven Evidence for a theory in one column,
Possible evidence not yet proven in another and then a column for arguments against it?

I am offering to be a scribe, using Google Sheets which can be publicly viewed by anyone with the link.

Here’s a starter…let’s plug in a theory and see how it works. Right now I have it set up for View permissions. We may be able to figure out a way to have multiple Editors, but for now I am going to populate it from what people tell me to put in.

The first step, after loading in a hypothesis, is to see if we need to add columns. I added No., Type, and Sub-type so we can classify and sort as the list grows.

CTS Collapse Spreadsheet

No.
Type
Sub-type
Theory/Hypothesis <short description>
Proven Evidence
Possible Evidence Not Yet Proven
Argument Against

 

[Optical98]

LOL Markbob, I have freely admitted to "not seeing clearly" many items on photos. I don't mind posting pics for discussion, or outright saying "what is this"?

I don't have a clue how much tar paper weighs, even looking at it on a pallet. I would venture to say if said pallet is as heavy as you say and it perhaps was sitting near a "left on" tar kettle on the eastern roof... that could be a problem. But we need to find these items on the ground at this point.

 

[Optical98]

MaudSTL

It might be easier to give each theory it's own tab? Under evidence there will likely have to be links to photos and articles etc. So it will grow, unless you don't mind inserting rows constantly.

A few theories to use for model -

Car vs Column
Roof failure from different objects, ac, tar kettle... actually their may be several
Pool Deck Failure

 

[gonefishing2]

15lb tar paper is very easy to tear, so I wonder on a commercial roof would you use say 30 lb instead?

Duck Duck Go Quick Quote Find:

"Weights and Measures of Underlayment for Roofing
May 19th, 2014
Share Now:

One of the most common questions when it comes to underlayment is whether one layer of #30 felt is the same as two layers of #15 felt? The short answer is no, but understanding the reason for needing two layers and the actual differences between the grades of underlayment is probably more important to know.


The traditional underlayment that has been utilized for many years and is still used today in steep-sloped roof applications is “asphalt saturated felt.” This product is commonly referred to as “felt paper,” “#15 felt,” or “#30 felt,” “building paper,” “felt underlayment,” or simply “underlayment.”

Underlayment is utilized under a variety of materials such as; asphalt shingles, wood shingles/shakes, metal roofing, metal shingles, slate, tile, and other synthetic steep-sloped roofing coverings. Underlayment can provide many functions for the roof assembly, including temporary protection for the substrate, creating a “cushion” or leveling layer below the roof covering, or act as a separation layer between the roof covering and the substrate.

Manufacturing organic asphalt-saturated felt underlayment is a pretty straightforward process. Recycled paper is processed into a roll. Hot asphalt is then added to the roll and asphalt saturated underlayment is the result.

In the past, the felt number designation was correlated to the weight of the felt (i.e., a 15# felt weighed 15 pounds/100 square feet). However, that direct correlation to weight no longer exists. By shifting the pound symbol, 15# felt became #15 felt, which may actually weigh 7.5 to 12.5 pounds per square; #30 felt can weigh between 16 and 27 pounds per square. Simple math shows that a single layer of #30 felt today could weigh more or less than two layers of #15 depending on which end of the min/max spectrum the two types of underlayment fall.

The need for two layers of felt is driven more by the deck slope and water management than actual weight.

Felt underlayment is water-resistant, but not waterproof. Felt’s perm rating varies but not by much. Dry, #15 felt is rated at 6 perms, #30 felt at 5 perms. The thicker #30 felt is more resistant to damage during installation of the roof-covering material, and will protect the roof longer if it should somehow become exposed to weather, but only applying one layer of underlayment on a low sloped roof does not offer the proper protection against water infiltration.

The lower the slope of the roof, 2:12 up to 4:12, the greater the chance of water working its way through to the substrate. Applying two layers of underlayment in a shingle fashion where the top layer overlaps the bottom layer by about 19 inches creates a stronger barrier against any wind driven water. One layer, regardless of how thick it is, will not provide the same protection.

Underlayment is a critical component of a home’s roofing system. Several factors such as roof covering and slope affect what and how it is installed. It’s not about weight, it’s about protection. One layer of #30 felt does not offer the same protection as two layers of #15. In fact, since the designations of #15 and #30 referring to the actual weights of the underlayment no longer apply. The terms Type I and Type II now are used within the industry, respectively, making it much easier to understand when it’s appropriate to use which type of underlayment."

 

[Demented]

Optical98, What is confusing to me is why each City with a Mayor, does not have there own PD. That is typically what I see in Inc towns. Out in the Counties the Sheriff’s typically are primary. How does all this work in Miami-Dade?

Does Surfside have their own Police Force? I can see making this a criminal investigation could be because of a deliberate or stupid act was trigger, but I can also see it is to protect Miami’s Condo Money Printing operation, and perhaps somewhat to keep folks calm and not thinking ever old Condo is at risk. If folks are scared away from Condo’s on Reclaimed Ocean, what happens to South Florida’s lively hood?

And then this could be an opportunity to condemn old Condo’s on prime real estate, so Developer’s can start urban renewal again to create new fatter profits?

Surfside has a PD, but it's no bigger than 8 officers. Most things in the tri-county area are run under Good ol' boys rule with the Sherriff's association, which MDPD is a part of.

Cavo recently signed off on large construction projects with the same firm behind the FIU bridge, among some other things. It's not unreasonable at this point for MDPD to suspect a multitude of wrongdoing, especially with the Morabito name tied to the roofing contractor that seems to have been doing the work unpermitted initially. Not to mention all of the other questionable permitting situations and stuff the town officials let slide.
Other buildings all throughout the area are still getting inspected and evacuated. It's a major issue it seems that's not local to this one particular building so there definitely is going to be a massive, drawn out investigation. Unfortunately as is all too common in FL, officials being investigated are often in charge of those investigating them, and retaliation firings are all too common.

The town of surfside has also recently been looking to invest major millions into underground tunnel projects.

It was a locked down crime scene from day 1 basically.


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

 

[waross]

MaudSTL.
A suggestion;
Add a column for the identity of contributors.

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

 

[Murph 9000]

When Cavo signed off on the ordered to demo, she stated that it would still take 2-4 weeks before all was planned and executed. But like whiplash, it was being prepped for demo a few days later.

She was working off what her advisers told her, which was reasonable advice and a reasonable fast timescale for most demolition contractors. Mark Loizeaux is not most demolition contractors, he's one of the top explosive demolition experts in the world, blowing up concrete and steel more or less continuously since he was a teenager, and now in his 70s. He is someone who can spend a few hours with the plans, walk the site, mark the spots for charges, and still pull it off with precision and just a day or two total planning. He had people back at his office helping, naturally, but he really is an artist / genius with explosives. From the sound of it, he could have done it quicker if they had signed off on his plan immediately.

That level of expertise can greatly shorten the timescale compared to reasonable estimates from advisers.

 

[Demented]

The photo of a PVC pipe with trap shown by Demented in section 08 and discussed further by Thermopile and Optical98 was really interesting because it shows that when they want to zoom in on an object in a video taken from a drone flying overhead, then they can see a 2 inch diameter object clearly enough to distinguish whether it’s a pipe or an electrical cable. Yet, they can’t see another zoomed object that is 36x36 inches square in another video.

This photo also intrigued me because of its high resolution. Not seeing Demented’s reference to the video until later, I tried to find a similar photo with the same high resolution and came up with one taken from a different perspective. And when I zoomed in on the green tarp behind the air conditioning units seen in Demented’s photo, look what I found:



It shows a green tarp covering rolls of tarpaper (aka roofing felt) on a wooden base. The rolls are almost all standing on end and there are 7 rolls in each direction, giving 49 rolls on the wooden base. On top of the rolls there is also a metal object of some sort. Since rolls of tarpaper are always 3 feet wide and one of the rolls is lying on its side, it is easy to verify that the wooden base is 6x6 feet. Depending on the thickness of the tarpaper, one roll can weigh between 35 and 85 pounds. Assuming 50 pounds per roll to be on the low side, this gives about 49x50 lbs = 2450 pounds plus the weight of the wooden base and the metal object, or about 2500 pounds, or over one ton. This corresponds to about 2500/36 ft2 = about 70 lbs/ft2. This is a heavy load on the roof of the 12th floor of the building that was still standing. If the same load was later placed on the penthouse roof with its thinner slab, then it seems like it might overload the penthouse roof and cause it to collapse. I’ll leave it for someone else to determine the maximum load for the penthouse roof and what the margin might be for collapse.

It just occurred to me that the Surfside building inspector was on the roof just the day before the collapse. Do you think he saw this high concentration of tarpaper in one area? Also, we have not seen any rolls of tarpaper on the debris pile anywhere. So, perhaps there was no similar green bag with tarpaper on the penthouse roof.

I am not above admitting I am wrong on something.
After all of this digging that led me up to a particular spot on the rough through permitted and unpermitted work, and having seen the TikTok video again not looking for anything other than to see if I could notice if the 20ft section leading to the garage collapsed.
Nothing stops a Trane.


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

 

[gonefishing2]

I second waross motion!!

 

[Demented]

If we have a 3/4" hole for a 5/8" anchor, what is the thickness of the roofing material? Our tar paper thickness is in there.

Edit: Uploaded original because potato upload. Find 5mm and 15mm paper.

 

[gonefishing2]

MarkBoB2 and Demented........ Amen.....

Edit for Demented: Yes I can see the previous re-roofer, said I have an ingenious idea....... I can save the Association Money, by roofing over the old roof and cut requiring labor and disposable costs... and of course you now have a double roof!!!
I also see that threaded anchor ran out of depth of concrete it appears?

And looks like it collided with STEEL.... Wonder how that could happen??? Let's see 6" slab would mean 1/2" to 5/8" bottom rebar would be 5/8" plus 3/4" above bottom of slab. So top of rebar would be at 4-3/4" down to say 4-5/8" down if I did the math right in my head?