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Pellegrine
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Re: Miami Condo Partially Collapsed

Thu Jul 15, 2021 5:20 am

https://youtu.be/ZUrHdwdZyWc

This structural engineer knows what he's talking about, and it is fascinating. A channel called Building Integrity on YT.
 
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flyingturtle
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Re: Miami Condo Partially Collapsed

Thu Jul 15, 2021 3:37 pm

Pellegrine wrote:
https://youtu.be/ZUrHdwdZyWc

This structural engineer knows what he's talking about, and it is fascinating. A channel called Building Integrity on YT.


I've watched every single one of his Surfside videos. Especially since the latest video, I cannot walk by a concrete structure without checking for spalling, water damage and other things...
 
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Pellegrine
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Re: Miami Condo Partially Collapsed

Sat Jul 17, 2021 2:47 am

flyingturtle wrote:
Pellegrine wrote:
https://youtu.be/ZUrHdwdZyWc

This structural engineer knows what he's talking about, and it is fascinating. A channel called Building Integrity on YT.


I've watched every single one of his Surfside videos. Especially since the latest video, I cannot walk by a concrete structure without checking for spalling, water damage and other things...


I know right?! I didn't know most of this before I started looking at his videos.
 
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Aaron747
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Re: Miami Condo Partially Collapsed

Sat Jul 17, 2021 2:52 am

flyingturtle wrote:
Pellegrine wrote:
https://youtu.be/ZUrHdwdZyWc

This structural engineer knows what he's talking about, and it is fascinating. A channel called Building Integrity on YT.


I've watched every single one of his Surfside videos. Especially since the latest video, I cannot walk by a concrete structure without checking for spalling, water damage and other things...


Not a good idea to get *too* paranoid because unless you are well versed in column placement, width, etc. it's hard to tell the difference just by looking from the outside between a primary concrete structure (w/rebar in columns) and primary steel frame structure that has concrete cladding on the exterior.
 
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casinterest
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Re: Miami Condo Partially Collapsed

Fri Jul 30, 2021 1:52 pm

Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?

https://www.usatoday.com/story/news/inv ... 413422001/

Some insurance companies have delayed payments or routed them to third parties. At least one – State Farm – has yet to decide if it will issue payments to Miller and possibly others.

Documents provided by USA TODAY show State Farm won't decide whether to pay until the cause of the collapse is determined – a process investigators say could take months if not years.


State Farm confirmed in a statement that it does not move forward with payments without the cause. The company did not answer questions about how many other Champlain Towers South residents it insures and whether they’re also awaiting payments.
 
PHLspecial
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Re: Miami Condo Partially Collapsed

Sun Aug 01, 2021 4:35 pm

casinterest wrote:
Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?

https://www.usatoday.com/story/news/inv ... 413422001/

Some insurance companies have delayed payments or routed them to third parties. At least one – State Farm – has yet to decide if it will issue payments to Miller and possibly others.

Documents provided by USA TODAY show State Farm won't decide whether to pay until the cause of the collapse is determined – a process investigators say could take months if not years.


State Farm confirmed in a statement that it does not move forward with payments without the cause. The company did not answer questions about how many other Champlain Towers South residents it insures and whether they’re also awaiting payments.

What would be the case that the insurance company wouldn't pay out?
 
Brick
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Re: Miami Condo Partially Collapsed

Sun Aug 01, 2021 5:12 pm

PHLspecial wrote:
What would be the case that the insurance company wouldn't pay out?


If the property owners are compensated from the sale of the land and are "made whole", then insurance will not pay out.

If you are in a car accident and the other driver pays out of their own pocket to repair your car, you can't go to their or your insurance company to make a claim. The other driver made you whole....you don't get paid twice for the accident.

In the case of the condo owners, I suspect that selling the land and distributing the proceeds to the owners will be much better for them financially that going through the insurance route. The owners will only have condo coverage that covers just the contents of the unit. The insurance policy for the building itself is held by the HOA. In case of an insurance payout to the HOA, each owner will get back what they paid into their unit, which in my opinion would likely be less than if the entire property was sold and distributed to all of the owners.
 
frmrCapCadet
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Re: Miami Condo Partially Collapsed

Sun Aug 01, 2021 9:58 pm

The insurance likely covers the building, not the land. That later likely is not covered. (Sea level rise eventually will affect the value of the land, and that would be separate insurance coverage.) Hence, the HOA insurance coverage most likely covers loss of building, each owners separate insurance covers the contents and some of the building. In catastrophic events usually every insurance company hands out its maximum to a judge, who when apportions out those settlements. In this case selling the land will be added to all of the insurance settlements. It gets complicated. The judge usually has the authority to apportion settlements to both owners and renters. It likely will be similar to an aircraft accident settlement.
 
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casinterest
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Re: Miami Condo Partially Collapsed

Mon Aug 02, 2021 1:15 am

PHLspecial wrote:
casinterest wrote:
Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?

https://www.usatoday.com/story/news/inv ... 413422001/

Some insurance companies have delayed payments or routed them to third parties. At least one – State Farm – has yet to decide if it will issue payments to Miller and possibly others.

Documents provided by USA TODAY show State Farm won't decide whether to pay until the cause of the collapse is determined – a process investigators say could take months if not years.


State Farm confirmed in a statement that it does not move forward with payments without the cause. The company did not answer questions about how many other Champlain Towers South residents it insures and whether they’re also awaiting payments.

What would be the case that the insurance company wouldn't pay out?
\

They want the root cause, and they do not want to pay out directly for homeowners rather than waiting to point fingers at the insurance company for the Condo association.
 
extender
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Re: Miami Condo Partially Collapsed

Tue Aug 10, 2021 9:24 am

The narrator can be a bit annoying, but recent footage which does illustrate initial damage images.

https://www.youtube.com/watch?v=9Hd2U8ELJpY
 
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Kiwirob
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Re: Miami Condo Partially Collapsed

Tue Aug 10, 2021 9:37 am

casinterest wrote:
Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?

https://www.usatoday.com/story/news/inv ... 413422001/

Some insurance companies have delayed payments or routed them to third parties. At least one – State Farm – has yet to decide if it will issue payments to Miller and possibly others.

Documents provided by USA TODAY show State Farm won't decide whether to pay until the cause of the collapse is determined – a process investigators say could take months if not years.


State Farm confirmed in a statement that it does not move forward with payments without the cause. The company did not answer questions about how many other Champlain Towers South residents it insures and whether they’re also awaiting payments.


I can't understand how you can have multiple insurers for the same building? I thought the body corp fees would also cover the buildings insurance?
 
extender
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Re: Miami Condo Partially Collapsed

Tue Aug 10, 2021 9:39 am

Condominiums have several policies. The owners usually have a policy for their contents.
 
ltbewr
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Re: Miami Condo Partially Collapsed

Tue Aug 10, 2021 12:03 pm

Kiwirob wrote:
casinterest wrote:
Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?
https://www.usatoday.com/story/news/inv ... 413422001/
Some insurance companies have delayed payments or routed them to third parties. At least one – State Farm – has yet to decide if it will issue payments to Miller and possibly others.
Documents provided by USA TODAY show State Farm won't decide whether to pay until the cause of the collapse is determined – a process investigators say could take months if not years.

State Farm confirmed in a statement that it does not move forward with payments without the cause. The company did not answer questions about how many other Champlain Towers South residents it insures and whether they’re also awaiting payments.

I can't understand how you can have multiple insurers for the same building? I thought the body corp fees would also cover the buildings insurance?

First of all as others have noted, each condo unit owner has insurance on their own, so a number of companies could be involved as to them.
As to the building and its corporate owner, likely there could be several policies involved, a primary and 'layers' of coverage by other parties. Up to first $1 million could be with company A, the next million of loss with company B and so on. Then each of those insurers of the layers have placed the risk with reinsurance where the risk is spread out to a number of companies (often via Lloyds of London). Each of the insurers of the layers and their reinsurers will want evidence that means they have to pay out claims. Property insurance is not like car insurance in many states where no-fault payments. The insurers of the building and the units will also seek to recover their losses in at least part by the sale of the land although that will likely be last in line as the families of dead unit occupants will get priority of monies in lawsuits and settlements from available of a property sale.
One issue I would like to bring up as to the insurers is their terrible underwriting of by them, a lack of inspections by them to determine their risk and mandating a certain level of maintenance to limit their losses. This is something that needs to happen by them to protect themselves from unnecessary losses.
 
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Kiwirob
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Re: Miami Condo Partially Collapsed

Tue Aug 10, 2021 12:29 pm

ltbewr wrote:
Kiwirob wrote:
casinterest wrote:
Can you imagine having an insurance company tell you that they will be waiting for months or years for the official cause of the accident?
https://www.usatoday.com/story/news/inv ... 413422001/


I can't understand how you can have multiple insurers for the same building? I thought the body corp fees would also cover the buildings insurance?

First of all as others have noted, each condo unit owner has insurance on their own, so a number of companies could be involved as to them.
As to the building and its corporate owner, likely there could be several policies involved, a primary and 'layers' of coverage by other parties. Up to first $1 million could be with company A, the next million of loss with company B and so on. Then each of those insurers of the layers have placed the risk with reinsurance where the risk is spread out to a number of companies (often via Lloyds of London). Each of the insurers of the layers and their reinsurers will want evidence that means they have to pay out claims. Property insurance is not like car insurance in many states where no-fault payments. The insurers of the building and the units will also seek to recover their losses in at least part by the sale of the land although that will likely be last in line as the families of dead unit occupants will get priority of monies in lawsuits and settlements from available of a property sale.
One issue I would like to bring up as to the insurers is their terrible underwriting of by them, a lack of inspections by them to determine their risk and mandating a certain level of maintenance to limit their losses. This is something that needs to happen by them to protect themselves from unnecessary losses.


thanks
 
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flyingturtle
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Re: Miami Condo Partially Collapsed

Sun Aug 15, 2021 11:24 am

Josh from Building Integrity posted a new, and quite long video.

He presents evidence that some columns were only able to carry the dead load - but not any live loads (like cars, and removable objects like planters). Only safety margins prevented an earlier collapse.

Between the original draft (1979) and the engineering drawings of 1980, there had been some substantial changes.

In the video, he says that he's surprised the building managed to stand for 40 years.

https://www.youtube.com/watch?v=WaZcyq7YsNA
 
extender
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Re: Miami Condo Partially Collapsed

Mon Aug 16, 2021 12:15 pm

Damning for sure. And I doubt he didn't run the number once or twice. He makes a logical argument for the initiator of the collapse. The omission of those beams for the steps is incredible.
 
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Aaron747
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Re: Miami Condo Partially Collapsed

Mon Aug 16, 2021 12:40 pm

extender wrote:
Damning for sure. And I doubt he didn't run the number once or twice. He makes a logical argument for the initiator of the collapse. The omission of those beams for the steps is incredible.


And for added fun the owners had three decades to shore up the shoddy original work and did jack shit.
 
StarAC17
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Re: Miami Condo Partially Collapsed

Tue Aug 17, 2021 3:49 am

flyingturtle wrote:
Josh from Building Integrity posted a new, and quite long video.

He presents evidence that some columns were only able to carry the dead load - but not any live loads (like cars, and removable objects like planters). Only safety margins prevented an earlier collapse.

Between the original draft (1979) and the engineering drawings of 1980, there had been some substantial changes.

In the video, he says that he's surprised the building managed to stand for 40 years.

https://www.youtube.com/watch?v=WaZcyq7YsNA


I'll have to re-watch where he said that. But all my concrete design knowledge and being in the field with this stuff comes back to me (I have a degree in Civil Engineering). He did say any live load on the pool deck would have been negligible, he is correct there

What I reckon caused this was (if you have watched these videos) is that the punch through failure of the pool slab tugged the 3 critical columns that he points out that are the edge of the slab. As the slab goes those columns are pulled towards the initial collapse of the pool slab creating a tensile force that even reinforceed concrete can't handle. This was the trigger the progressive collapse because all other columns have a minimal factor of safety.

The planters and the deck had long expired waterproofing that causes unseen reinforcement deterioration and spalling on the top of the slab that accelerated the collapse in a manner that was unseen. Spalling on the top of a slab won't fall on to cars. As she showed in one of the videos the concrete on top cracks off but is sandwiched by the slab and the top of the deck.

Waterproofing expires. The condo I live in is ripping out a large section of our pool courtyard in the fall to do exactly this. We don't have a concrete deck but have a grass field. They can repair any damage and replace the waterproofing.

What does surprise me is that the foundation and garage slabs remain very much intact meaning that the foundation was in fact solid.

This will likely be concluded to be a poor design due to insufficient building codes at the time. IIRC Miami codes were beefed up due to Andrew and negligence caused this.
 
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Aesma
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Re: Miami Condo Partially Collapsed

Tue Aug 17, 2021 8:58 am

What I don't get is why the concrete slabs seem to be laid on top of the columns, maybe with a bit of rebar, but nothing larger than the column to transfer the loads on a larger surface. Then for the columns to punch through would be a lot more difficult.

If you look at the Parthenon in Athens there are caps on top of the columns and this was build 2500 years ago.
 
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Aaron747
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Re: Miami Condo Partially Collapsed

Tue Aug 17, 2021 9:33 am

Aesma wrote:
What I don't get is why the concrete slabs seem to be laid on top of the columns, maybe with a bit of rebar, but nothing larger than the column to transfer the loads on a larger surface. Then for the columns to punch through would be a lot more difficult.

If you look at the Parthenon in Athens there are caps on top of the columns and this was build 2500 years ago.


Doing the job on the cheap is your answer.
 
frmrCapCadet
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Re: Miami Condo Partially Collapsed

Tue Aug 17, 2021 12:24 pm

I understand that entire chapters are being written on steel reinforced concrete buildings. We tend to think they are about as eternal as the Parthenon and some of the Roman concrete constructions. They are not. That steel is definitely capable of becoming the weak and fatal link. Electrolysis is not just about hair removal. It can be the ruin of that steel in the concrete. I write with three of those large columns in our main room supporting all of the floors above our unit. Are we scared? No. Are we concerned? As the former governor of Alaska would put it, You Betcha.
 
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flyingturtle
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 2:55 pm

Josh the Engineer did a new video. This time, on the historical aspects of the building:

https://www.youtube.com/watch?v=pk2hmytlDg8

Some keywords:
- the owner of the building - and the company responsible for building it - were the same entity, making it easier to cut corners
- at the time, town officials reponsible for approving building permits were paid a symbolic sum of $1 per year, making them susceptible to bribes and bribing attempts
- during the building period, a 13th story (the penthouse) was added, despite only 12 stories being allowed due to zoning rules. The town council was intimidated into approving the change, even when the building plans were not revised. Huh... additional weight, anybody?
- the architect was also responsible for another building that had serious flaws. He had trouble understanding what "load-bearing" walls were.
- when Morabito, the engineering company contracted with the 40-year review, issued their damning report, there was a HOA meeting - where a town councillor was invited. The guy responsible for, uh, approving the review. He said the building was in a great shape, which surely made an impression on the condo owners.
 
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Aaron747
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 3:04 pm

flyingturtle wrote:
Josh the Engineer did a new video. This time, on the historical aspects of the building:

https://www.youtube.com/watch?v=pk2hmytlDg8

Some keywords:
- the owner of the building - and the company responsible for building it - were the same entity, making it easier to cut corners
- at the time, town officials reponsible for approving building permits were paid a symbolic sum of $1 per year, making them susceptible to bribes and bribing attempts
- during the building period, a 13th story (the penthouse) was added, despite only 12 stories being allowed due to zoning rules. The town council was intimidated into approving the change, even when the building plans were not revised. Huh... additional weight, anybody?
- the architect was also responsible for another building that had serious flaws. He had trouble understanding what "load-bearing" walls were.
- when Morabito, the engineering company contracted with the 40-year review, issued their damning report, there was a HOA meeting - where a town councillor was invited. The guy responsible for, uh, approving the review. He said the building was in a great shape, which surely made an impression on the condo owners.


Wow based on that narrative the architect and town permitting officer sound criminally negligent.
 
Newark727
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 3:13 pm

flyingturtle wrote:
Josh the Engineer did a new video. This time, on the historical aspects of the building:

https://www.youtube.com/watch?v=pk2hmytlDg8

Some keywords:
- the owner of the building - and the company responsible for building it - were the same entity, making it easier to cut corners
- at the time, town officials reponsible for approving building permits were paid a symbolic sum of $1 per year, making them susceptible to bribes and bribing attempts
- during the building period, a 13th story (the penthouse) was added, despite only 12 stories being allowed due to zoning rules. The town council was intimidated into approving the change, even when the building plans were not revised. Huh... additional weight, anybody?
- the architect was also responsible for another building that had serious flaws. He had trouble understanding what "load-bearing" walls were.
- when Morabito, the engineering company contracted with the 40-year review, issued their damning report, there was a HOA meeting - where a town councillor was invited. The guy responsible for, uh, approving the review. He said the building was in a great shape, which surely made an impression on the condo owners.


Reading those bullet points, the surprise becomes less that the building fell down, and more that it stayed up as long as it did...
 
StarAC17
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 5:17 pm

flyingturtle wrote:
Josh the Engineer did a new video. This time, on the historical aspects of the building:

https://www.youtube.com/watch?v=pk2hmytlDg8
Some keywords:
- the owner of the building - and the company responsible for building it - were the same entity, making it easier to cut corners
- at the time, town officials reponsible for approving building permits were paid a symbolic sum of $1 per year, making them susceptible to bribes and bribing attempts
- during the building period, a 13th story (the penthouse) was added, despite only 12 stories being allowed due to zoning rules. The town council was intimidated into approving the change, even when the building plans were not revised. Huh... additional weight, anybody?
- the architect was also responsible for another building that had serious flaws. He had trouble understanding what "load-bearing" walls were.
- when Morabito, the engineering company contracted with the 40-year review, issued their damning report, there was a HOA meeting - where a town councillor was invited. The guy responsible for, uh, approving the review. He said the building was in a great shape, which surely made an impression on the condo owners.


I will watch this tonight.

Architects and Engineers don't like each other. Architects want to make the building look sexy, engineers ensure it doesn't fall down.

I have a degree in civil engineering (I don't practice it anymore, never did any structural work but did Geotechnical and foundations) but it also seems that these columns had basically no factor of safety. The foundation look actually very well done and held up for the most part. The failure was in the columns, and had they

In Canada and I am sure many jurisdictions in the US today (not 1980) you need at least a factor of safety of 2 or 3 to ensure that structures aren't going anywhere. Had this building had that then the structural columns that connected that pool deck slab may have failed but that building isn't falling down in that case because the 3 critical columns Josh speaks about might have still sheared away but the other ones are holding the building up.

Codes today especially after Hurricane Andrew are much more strict but money has to be spent to look at these buildings with a toothcomb to ensure the structural integrity is solid or this will happen again.

Some modern engineering fails really baffle me.

If I had to sign off on the foundation of the Millennium tower in San Francisco I would have failed that design out of university. Whoever thought that it was a good idea to not put a foundation to bedrock in a city composed of reclaimed land, in a known seismic zone where we saw in 1906 and 1989 what happens when you shake reclaimed land. It liquifies. It also ends up costing more to fix than if done right to begin with.
 
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Aaron747
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 5:35 pm

StarAC17 wrote:
If I had to sign off on the foundation of the Millennium tower in San Francisco I would have failed that design out of university. Whoever thought that it was a good idea to not put a foundation to bedrock in a city composed of reclaimed land, in a known seismic zone where we saw in 1906 and 1989 what happens when you shake reclaimed land. It liquifies. It also ends up costing more to fix than if done right to begin with.


That's definitely a head-scratcher too. What's more the engineering team on that one managed to bamboozle the permit inspectors and convince them it was all good (or more likely they were incompetent). Now the 'fix' has made the situation worse, if you are keeping up:

https://www.youtube.com/watch?v=V-vJob0PnmA
 
LCDFlight
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 9:17 pm

frmrCapCadet wrote:
I understand that entire chapters are being written on steel reinforced concrete buildings. We tend to think they are about as eternal as the Parthenon and some of the Roman concrete constructions. They are not. That steel is definitely capable of becoming the weak and fatal link. Electrolysis is not just about hair removal. It can be the ruin of that steel in the concrete. I write with three of those large columns in our main room supporting all of the floors above our unit. Are we scared? No. Are we concerned? As the former governor of Alaska would put it, You Betcha.


As a novice, it seems to me that we made a huge mistake relying so very much on steel rebar reinforced concrete across global society.

Shouldn’t we stop routine use of this? In some ways this is one of the most pressing issues in society. All of that rebar is going to spall and the concrete will fail. There has to be a better way.

No doubt our stuff is more cost efficient and stronger than Roman concrete (at first). But around year 50-80, or maybe 150 for the Hoover Dam, we are in trouble, right?
 
StarAC17
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 10:33 pm

frmrCapCadet wrote:
I understand that entire chapters are being written on steel reinforced concrete buildings. We tend to think they are about as eternal as the Parthenon and some of the Roman concrete constructions. They are not. That steel is definitely capable of becoming the weak and fatal link. Electrolysis is not just about hair removal. It can be the ruin of that steel in the concrete. I write with three of those large columns in our main room supporting all of the floors above our unit. Are we scared? No. Are we concerned? As the former governor of Alaska would put it, You Betcha.


What exactly are you concerned about? Concrete doesn't spall for no reason at all, it happens because the steel inside is exposed to water, rusts and expands. Cracks appear first and then if the problem persists spalling happens. Spalling isn't a sign of an immediate collapse but a warning and concrete is designed to warn when there is an issue. Those warnings for this building were ignored with deadly consequences.

If reinforced concrete is in a low to moderate level of moisture and heavy water intrusion isn't present, reinforced concrete structures can last centuries.

LCDFlight wrote:
frmrCapCadet wrote:
I understand that entire chapters are being written on steel reinforced concrete buildings. We tend to think they are about as eternal as the Parthenon and some of the Roman concrete constructions. They are not. That steel is definitely capable of becoming the weak and fatal link. Electrolysis is not just about hair removal. It can be the ruin of that steel in the concrete. I write with three of those large columns in our main room supporting all of the floors above our unit. Are we scared? No. Are we concerned? As the former governor of Alaska would put it, You Betcha.


As a novice, it seems to me that we made a huge mistake relying so very much on steel rebar reinforced concrete across global society.

Shouldn’t we stop routine use of this? In some ways this is one of the most pressing issues in society. All of that rebar is going to spall and the concrete will fail. There has to be a better way.

No doubt our stuff is more cost efficient and stronger than Roman concrete (at first). But around year 50-80, or maybe 150 for the Hoover Dam, we are in trouble, right?


What other material do you think would provide a similar level of stability as a comparable cost?

Hoover dam isn't going anywhere. That has so much reinforced concrete that I don't even think its beginning to deteriorate and any capacity and its nearly 100 years old. It would take an earthquake that would turn Las Vegas to rubble to collapse that thing and even then I'm betting on the dam.

This disaster was caused by gross negligence and an under-engineered building. Also rebar only causes concrete to spalls if it rusts and rust happens when steel is saturated in salt, water or saltwater. If there is adequate waterproofing and drainage that concrete can last a long time. Repairs will need to be done from time to time but no building will be condemned because of a little bit of spalling
 
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Tugger
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 11:11 pm

LCDFlight wrote:
No doubt our stuff is more cost efficient and stronger than Roman concrete (at first). But around year 50-80, or maybe 150 for the Hoover Dam, we are in trouble, right?

Actually Roman concrete is in some ways superior the current standard bearer that uses portland Cement. But that doesn't mean it is all round better than what we can do today. There are many formulations of concrete and they actually haven't been able to reproduce Roman concrete so far. It has unique properties (like a lot more shell for one!) that make it both strong and stable (long lasting). The "rebar" they used back then was essentially straw or reeds, so as you note with no steel it lasts longer.

And don't worry about Hoover dam and others. Check out the first article below.

https://www.autodesk.com/autodesk-unive ... crete-2016
https://practical.engineering/blog/2019 ... ete-better
https://www.ascconline.org/Portals/0/Te ... _WebSC.pdf

And as to not using steel due its inherent issue in concrete, I'm thinking someday they'll do something like us carbon-fiber thread or rods throughout.

Tugg
 
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flyingturtle
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Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 11:17 pm

Aaron747 wrote:
flyingturtle wrote:
Josh the Engineer did a new video. This time, on the historical aspects of the building:

......


Wow based on that narrative the architect and town permitting officer sound criminally negligent.


In Switzerland, there was once a serious construction flaw with an underground parking area. The engineer did nothing wrong... but the building company put too much soil on the roof; too much for the columns. When firemen responded to a car fire, the whole thing collapsed with several firemen killed.

Because of our 10 year statute of limitation in case of negligent homicide, nobody was prosecuted. The building was 12 years old when it came down...
 
StarAC17
Posts: 4158
Joined: Thu Aug 07, 2003 11:54 am

Re: Miami Condo Partially Collapsed

Wed Sep 22, 2021 11:51 pm

Tugger wrote:
LCDFlight wrote:
No doubt our stuff is more cost efficient and stronger than Roman concrete (at first). But around year 50-80, or maybe 150 for the Hoover Dam, we are in trouble, right?

Actually Roman concrete is in some ways superior the current standard bearer that uses portland Cement. But that doesn't mean it is all round better than what we can do today. There are many formulations of concrete and they actually haven't been able to reproduce Roman concrete so far. It has unique properties (like a lot more shell for one!) that make it both strong and stable (long lasting). The "rebar" they used back then was essentially straw or reeds, so as you note with no steel it lasts longer.

And don't worry about Hoover dam and others. Check out the first article below.

https://www.autodesk.com/autodesk-unive ... crete-2016
https://practical.engineering/blog/2019 ... ete-better
https://www.ascconline.org/Portals/0/Te ... _WebSC.pdf

And as to not using steel due its inherent issue in concrete, I'm thinking someday they'll do something like us carbon-fiber thread or rods throughout.

Tugg


You have to look at cost as a factor at using Carbon fibre reinforcements. The cost would be prohibitive for a lot of public works projects. You could make a case that it could be used in an area like Miami where saltwater intrusion is an issue or foundations that are in water such as bridge foundations of and columns over water.

Adequate waterproofing and maintenance do the job but waterproofing needs to be replaced often.

Stainless steel would be a good alternative that wouldn't be a much bigger expense compared to carbon fibre.
 
extender
Posts: 979
Joined: Thu Oct 18, 2007 2:52 am

Re: Miami Condo Partially Collapsed

Thu Sep 23, 2021 11:56 am

StarAC17 wrote:
Stainless steel would be a good alternative that wouldn't be a much bigger expense compared to carbon fibre.


Plating? Perhaps cad plating? There is epoxy coated rebar already, but that has its own limitations.
 
frmrCapCadet
Posts: 5047
Joined: Thu May 29, 2008 8:24 pm

Re: Miami Condo Partially Collapsed

Wed Oct 13, 2021 2:11 pm

https://www.bloomberg.com/graphics/2021 ... nd=premium

This has a fair amount of technical data in it, including what can go wrong with reinforced concrete construction. Contrary to some posters it has significant issues. I know. We are facing some on our building, fortunately only moderately expensive to fix.
 
T4thH
Posts: 1276
Joined: Thu Jun 06, 2019 11:17 pm

Re: Miami Condo Partially Collapsed

Wed Oct 13, 2021 2:51 pm

extender wrote:
StarAC17 wrote:
Stainless steel would be a good alternative that wouldn't be a much bigger expense compared to carbon fibre.


Plating? Perhaps cad plating? There is epoxy coated rebar already, but that has its own limitations.

Sorry, why you are always asking for the "high end solution"?
Throw in industrial ash and than you have not any more to think about for the next hundred years. It is a replacement and doing the same as the Puzzolan or the Chinese rice water with the exception of, that Puzzolan is limited available. And industrial ash....has to be disposed expensively or can be used for something else.

Just remind, the roman concrete buildings are still standing as also the Chinese wall. There is a reason, why the European/global concrete and chemical industry are spending hundred of millions in basic research.
Alone in Germany there is already 3 of the 3.5 mio t fly ash reused. And in the right mixture and the rights forms, it can do the same as Puzzolan.

One of many sources in German:
https://www.baustoffwissen.de/baustoffe/baustoffknowhow/grundstoffe-des-bauens/aschen-und-schlacken-wertvolle-zuschlagstoffe-fuer-baustoffe/
 
StarAC17
Posts: 4158
Joined: Thu Aug 07, 2003 11:54 am

Re: Miami Condo Partially Collapsed

Wed Oct 13, 2021 3:52 pm

T4thH wrote:
extender wrote:
StarAC17 wrote:
Stainless steel would be a good alternative that wouldn't be a much bigger expense compared to carbon fibre.


Plating? Perhaps cad plating? There is epoxy coated rebar already, but that has its own limitations.

Sorry, why you are always asking for the "high end solution"?
Throw in industrial ash and than you have not any more to think about for the next hundred years. It is a replacement and doing the same as the Puzzolan or the Chinese rice water with the exception of, that Puzzolan is limited available. And industrial ash....has to be disposed expensively or can be used for something else.

Just remind, the roman concrete buildings are still standing as also the Chinese wall. There is a reason, why the European/global concrete and chemical industry are spending hundred of millions in basic research.
Alone in Germany there is already 3 of the 3.5 mio t fly ash reused. And in the right mixture and the rights forms, it can do the same as Puzzolan.

One of many sources in German:
https://www.baustoffwissen.de/baustoffe/baustoffknowhow/grundstoffe-des-bauens/aschen-und-schlacken-wertvolle-zuschlagstoffe-fuer-baustoffe/


The big thing is cost for those additives and are absolutely used from time to time depending on the purpose, also these structures aren't facing the loads that buildings and modern bridges face so they can last. You are not driving 18 wheelers on the great Wall of China or a Roman aqueduct.

While those ancient buildings are standing up well many don't face high tensile loads that steel reinforcement allows for (concrete is about 10 fold stronger in compression than in tension and the steel evens that out). With the steel reinforcement there is always the risk of rust which leads to concrete deterioration such as cracks and spalling as concrete it not an impermeable surface

The reinforcement means less concrete needs to be used (cost savings) and thus buildings can be lighter and built quicker.
 
T4thH
Posts: 1276
Joined: Thu Jun 06, 2019 11:17 pm

Re: Miami Condo Partially Collapsed

Wed Oct 13, 2021 4:12 pm

StarAC17 wrote:
T4thH wrote:
extender wrote:

Plating? Perhaps cad plating? There is epoxy coated rebar already, but that has its own limitations.

Sorry, why you are always asking for the "high end solution"?
Throw in industrial ash and than you have not any more to think about for the next hundred years. It is a replacement and doing the same as the Puzzolan or the Chinese rice water with the exception of, that Puzzolan is limited available. And industrial ash....has to be disposed expensively or can be used for something else.

Just remind, the roman concrete buildings are still standing as also the Chinese wall. There is a reason, why the European/global concrete and chemical industry are spending hundred of millions in basic research.
Alone in Germany there is already 3 of the 3.5 mio t fly ash reused. And in the right mixture and the rights forms, it can do the same as Puzzolan.

Please note:

One of many sources in German:
https://www.baustoffwissen.de/baustoffe/baustoffknowhow/grundstoffe-des-bauens/aschen-und-schlacken-wertvolle-zuschlagstoffe-fuer-baustoffe/


The big thing is cost for those additives and are absolutely used from time to time depending on the purpose, also these structures aren't facing the loads that buildings and modern bridges face so they can last. You are not driving 18 wheelers on the great Wall of China or a Roman aqueduct.

While those ancient buildings are standing up well many don't face high tensile loads that steel reinforcement allows for (concrete is about 10 fold stronger in compression than in tension and the steel evens that out). With the steel reinforcement there is always the risk of rust which leads to concrete deterioration such as cracks and spalling as concrete it not an impermeable surface

The reinforcement means less concrete needs to be used (cost savings) and thus buildings can be lighter and built quicker.

https://en.wikipedia.org/wiki/Roman_Bridge_(Trier)
Sorry, why trucks or busses shall not drive over the roman pillars off the bridge? Why it shall not work, I do not understand. Please note, you have not to swim if you want to cross the bridge with a bus. Or let us say, I had not to swim.
Please note, the issue is not the steel/iron inside off the concrete, it is the protection of the steel inside of the concrete from acids, water and oxygen. And you have to change the crystal structure and the strength of the concrete.
Please note, we are now in the year 2021, in the last 5 to10 years the basic research in Europe/Germany has identified many solutions, which are successful, cheap and already in regular use by companies like HeidelbergCement.

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