Miami Beach, Champlain Towers South apartment building collapse, Part 12 60

[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

SF Charlie
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[TheGreenLama]

@Nukeman948,

For test to be effective I would think they would have had to chip out fdn slab to expose a lone Franki pile (No comment of effectiveness of PDA on Franki piles). And it is likely that they are working in that area simply because it is away from the collapse event. Piles near collapse may have been damaged.

 

[Vance Wiley]

Thanks, Charlie. You ARE the master of drill downs in my book.
I was able to get to and now I just need to sell my house to cover the cost and I will be good.
In today's code, using lap splices, the max reinforcing in a column is 4% (as I interpret the code) because the lap splice zone is limited to 8%.
That may not have been the case in 1980.
In my mind I had thought the max reinforcing was 4% and the purpose was to prevent brittle and abrupt failures.
Today we have products which can flow and maintain strength and could be used in congested areas - there is a minimum limit dimensionally of course, and the cost rises. Another 2 inches on the column dimension or an extra 1000 psi on concrete strength would be less expensive, I think.

 

[SFCharlie]

Regarding ConeTec (as spotted by AusG), I found no specific mention of DLT on their website, but they are clearly specialists in doing geotechnical site investigations.

I noticed:
Drilling, and:
geophysical-testing
Including
MULTI-CHANNEL ANALYSIS OF SURFACE WAVES
So, maybe, drop the weight, and record the echoes???)

SF Charlie
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[Vance Wiley]

I appreciate that and I agree with you there.
This ball of string has gotten away from me and I am trying to collect the ends to prevent leaving bad information here.
Thanks for the help.

 

[TheGreenLama]

For those currently debating % steel and lap splices let me add my two cents.

Staggered lap splices are common.

Couplers are sometimes given as an option for contractors. I have a sense, though, that these are a costly option.

Using couplers for outside/perimeter column bars may be impacted by two things: maintaining minimum concrete cover (as a coupled bar now has an increased diameter); interference w/ the shear/confinement steel. You always want to situate your column steel as close to the edge as possible, and shear steel interference w/ coupled bars may impact the use of couplers.

 

[SFCharlie]

and now I just need to sell my house to cover the cost and I will be good.

Depending on your PC, you might try downloading the .pdf:
ACI 318: Building Code Requirements for Reinforced Concrete
It's Big
(finally got it to open, it's the 1995 version.)

edit: one may buy a used hardcover on Amazon for $120 +$4 shipping

 

[SFCharlie]

and now I just need to sell my house to cover the cost and I will be good.

Attached is a .pdf of chapter 10.6. It is not searchable, but it is small.
If there are other chapters you would like, just ask...

SF Charlie
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[dik]

My earliest edition is the '63...

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

-Dik

 

[SFCharlie]

Attached is a .pdf of chapters 10.7. 10.8 Again it's not searchable, but small.

SF Charlie
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[TheGreenLama]

@Vance Wiley,

Found a PDF online that is labeled as a 1980 "Technical Release" for use by the USDA that is supposedly based on ACI 318-77. User beware.

https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=18640.wba

 

[Vance Wiley]

Charlie - thank you so much - but - your clip starts at 10.7 and in the ACI 318-19 the the % reinforcing is Chapter 10.6. I hate to wear out my welcome, but if it is not too much trouble and if 10.6 is available to you - -please?
Many thanks, and an old phrase "Much Obliged".

 

[Nukeman948]

Maybe they don't know we are watching?
Please like and comment
Let YouTube and Them know you care! Thanks

I would normally agree with letting them know we like their content but this is not a youtube live cam. It is a NEST cam that is owned by the same people that have the drone video but they do not share a link for the NEST cam on their youtube page. If they want it hidden, I'm not going to draw extra attention to it. Some people really want to restrict sharing info with other people. I think the facebook page I was on is theirs also and they are searching for spies that are stealing their info and not giving credit to them. Something about a "fake youtube engineer" making videos with their research.

This post will self destruct as soon as you finish reading it.

 

[SFCharlie]

if 10.6 is available to you

Please see above:

Attached is a .pdf of chapter 10.6. It is not searchable, but it is small.

SF Charlie
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[Optical98]

Here is an online design code calc using ACI-318-2014

https://skyciv.com/concrete-footing-calculator/

 

[Vance Wiley]

Thank you.. I scanned thru to the end and revisited the first 60 pages -I did not find anything addressing columns or amount of reinforcing in columns.
I do appreciate the effort. And I will beware.

 

[SFCharlie]

Please find attached a "table of Contents" for:
Building Code Requirements for
Structural Concrete (ACI 318-95)
and Commentary (ACI 318R-95)


SF Charlie
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[dik]

FYI

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1630272552/tips/ACI-Ch_10_dybsxp.pdf[/url]

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

-Dik

 

[Optical98]

This was interesting to listen to, maybe start at around 20:00

August 25, 2021 Building Membership Council Governing Committee meeting

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

 

[AusG]

MASW

Nice thought but nope. I have done some Multichannel analysis of surface wave MASW for geotech in limestone terrain and all you need is a FBH and someone's big dumb nephew to swing it. All that heavy hardware would just complicate things. Also I'm not seeing strings of geophones laid out. MASW would be the correct seismic technique for this job so maybe we'll see that later.

 

[Vance Wiley]

You are a hard man to keep up with, Charlie.
You had already sent 10.+. Your clip of 10.7 and 10.8 carries over to 10.9 and that addresses maximum reinforcing in compression members ( columns).
It clearly states minimum As is 1%Ag and maximum As is 8%Ag. The comment recommends As max of 4% if splices are lapped.
Note that it is a recommendation. So if the columns at CTS have 6% reinforcing that was not a code violation - just ignoring a recommendation. And is not permitted in current codes, practices, or recommendations by several Structurals on this forum.
I can put this to rest now. I will not use more than 4% steel in a concrete column.
Thanks, everyone.
WAIT !!
Charlie - were the clips you sent from a 1995 edition of ACI 318? If so that leaves me wondering how the 1977 edition addressed this. No sleep yet - - - disregard prior comments herein.