Miami Beach, Champlain Towers South apartment building collapse, Part 11 54

[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


SF Charlie
Eng-Tips.com Forum Policies

 

[Vance Wiley]

Shucks. Shows the need to verify sources and basis before proceeding any further.
Propaganda - the medium which carried it suggests that.
Thank you,

 

[gonefishing2]

Attached is the Full paper titled 'A preliminary analysis and discussion of the condominium building collapse in surfside, Florida, US, June 24, 2021'

August 2021 Frontiers of Structural and Civil Engineering
DOI:10.1007/s11709-021-0766-0
Authors:
Xinzheng Lu at Tsinghua University
Hong Guan
Hailin Sun
Yi Li

 

[Santos81]

Shows the need to verify sources and basis before proceeding any further.

I found the doesn’t meet Chinese Code GB50010 (which the calcs are based on) to be the reddest herring follows by the inclusion of Type B columns, etc etc.

Attached is the…

Might want to run a thorough and up to date Mal-ware scan.

 

[gonefishing2]

Well I ran a scan on attachment for you Windows Fans, and it came back clean.... One advantage of using a Mac. I used Bit Defender which looks for PC and Mac Malware.

 

[AusG]

Given all the educated middle class and CCP-connected folks who have their savings and lives invested in hastily-built concrete apartment towers I'm not surprised there is great interest in seeing a reassuring study separating this building from those that several hundred million people live in. ETA: I think this paper does that without claiming any greater knowledge. I see an email contact listed for the corresponding author. If there are documentable errors it would improve the next stage of their work to correct them.

 

[Sym P. le]

"We acknowledge that this work is a preliminary study. The analyses and conclusions of this work are based on
the available information with certain assumptions and simplifications. As such, the study outcomes are not
anticipated to be used directly for forensic analyses or any other technical purposes. The intended purpose of this
work is to provide a reference base for the forthcoming detailed forensic analyses and discussions of the cause of
the failure of the Miami condominium building"

I don't think there is any pretense about the substance of this paper. It suggests that certain columns are inadequate, that the east wing of the building lacks shear resistance and lays out their method of analysis. If someone can improve on this, I'm all ears.

 

[Vance Wiley]

A question about groundwater and water tables near the coast, please.
It seems to me the sea level (average) would set the depth to water at the site of the CTS. And likely for some distance depending on the soil/sand/rock found inland. After a few million years everything should be sea level??
So what good does a 24" x 24" well do? I can see perhaps extending it 40 feet above the water table but that creates very little storage volume and flow is likely quite slow. A comment, anyone?
I can see the benefit of injection of fresh water to push back on the salt water.
And are they someday going to need a sea wall around Miami and locks to pass ships to the docks?
There seems to be concern in San Francisco about enough fresh water flowing into the bay to keep the salt water out. It seems that a dam and gates and one way valves under/near the Golden Gate Bridge could be an answer.
Big $$ I know but locks might not be needed - there is no change in elevation, just a double gate section for ships.
But SF is a continent away from CTS.
Thanks ,

 

[SFCharlie]

concern in San Francisco about enough fresh water flowing into the bay to keep the salt water out

San Francisco would do better to drill a tunnel from their Oceanside Water Pollution Control Plant to the bay and dump their fresh treated water there. St, Louis Mo. uses river water for their drink water that has been recycled about fifteen times. Communities upstream, filter and sanitize it for drinking water and then treat it, returning it to streams that run into the Missouri and Mississippi Rivers. Luckily, the MUD flocculates the BEASTIES (MUD and BEASTIES are scientific terms for the content of the Big Muddy, and people poop (microsoft assures me this is childish language)). So they filter out the muddy beasties and sterilize the water (with LOTS of choline).
Not only did the marine traffic establish the City, but the ports (Benicia (import cars) Martinez (petroleum in and out), Oakland (Containers) and SF (tourists) still are major contributors to our economy.
But, yes, SF is a continent away from CTS

 

[Vance Wiley]

I like your idea more better - much cheaper - no moving parts. It seems the state requires 50% of mountain runoff must go to the sea, 40% to farmers, and 10% to humans. So it makes great sense to hit the humans with the burden of saving enough water to save the state.
The Asian Carp love Big Muddy - I think we should give the bay smelt a chance to enjoy similar conditions and your idea fits SO well.

 

[Vance Wiley]

https://twitter.com/XinzhengLu/status/142612984022...[/URL]]

Starting with the post referenced, I recall Column L-8 (I think) was reported to be loaded to 1.89 X or "axial compression load ratio".
So I had to check. This is rough and quick. I see L-8 has 23' X 22 ' is 506 sf trib ea floor, is 12X24 size, and has 12-#10 bars in the lower section. This is from the drawings posted previously and may not be the final conditions.
Using slab weight and 15 psf added dead load and 10 psf real live load, all unfactored, I see 861 Kips real DL and 70 Kips real Live Load, for a total of 931 Kips axial only below the Basement.
I have long forgotten the reduction factors for columns but 4 KSI x 12 x 24 =1152 Kips and 15 in^2x 40 KSI = 600 Kips for a total of 1752 Kips at 100% (no phi), Now if phi is 0.60 that gives a possible capacity in the order of 1051 Kips.
So we have something like 931 Kips real load in the lower section of the column and a reasonable capacity of 1051 Kips. Too close for comfort but likely stable if all components contribute as expected and loads used are representative of conditions at the time. BUT little room for moments and secondary stresses.
Takeaway - for this quick examination the column should have supported the load. And it did for 40 years.
The numbers and relationships and factors can be pushed in many directions, but I do not yet see a failure due to inadequate design of this column. A more exacting analysis may reveal otherwise.

 

[SFCharlie]

I seem to remember (BuildingIntegrity) that the 50 ton+/- planters aren't on the prints?

SF Charlie
Eng-Tips.com Forum Policies

 

[AusG]

Yes. Standing water level in permeable ground is close to but slightly higher than the level of a nearby body of water. Higher because of infiltrating rainwater (etc) moving seaward. A well is just a more efficient means of connecting a water source to that movement. In porous sand between two adjacent arms of the ocean the SWL will be within a few inches of sea level and will move with tides to some extent.

 

[MaudSTL]

San Francisco would do better to drill a tunnel from their Oceanside Water Pollution Control Plant to the bay and dump their fresh treated water there. St, Louis Mo. uses river water for their drink water that has been recycled about fifteen times.

A wise recommendation. The City of St. Louis (which is a separate entity from St. Louis County) does have excellent tap water, which is one of the reasons why we also have such good restaurants. This piece describes how we purify mostly Missouri River water, using lime and ferric sulfate to precipitate the sediments, and definitely return cleaner water to the Mississippi than what arrived in our intakes.

 

[gonefishing2]

Ok I am trying to understand the California Political Force, by exploring the mandated California Water Allocations. We read in the news that California does not have enough fresh water, and looking at the dropping levels of Lake Mead, we know where California is getting a lot of water from a shrinking resource.

We also know Sea Levels are rising, so why on earth would California require that 50% of Mountain Fresh Water Runoff be dumped/wasted in the ocean rather than using that fresh water to meet California human needs, and farmers needs, etc???

Why waste that fresh water source when fresh water is scare in California?

It reminds me of California also allowing brush to grow up around power lines, and then enjoy the brown outs....

Edit: I don't think it is possible to save California from their Political Agenda's....

 

[SFCharlie]

Easier that saving the citizens of FL and TX from theirs?

SF Charlie
Eng-Tips.com Forum Policies

 

[SFCharlie]

Maybe we can reverse the California Aqueduct and ship fresh treated water from LA (the one near San Diego) back north to the farmers. Humm... How can I make water flow uphill?

SF Charlie
Eng-Tips.com Forum Policies

 

[gonefishing2]

SFCharlie, excellent Point!

Edit: What about injection wells so water can flow laterally via underground aquifer?

Edit2: I know put Engineers in charge of everything!

 

[Demented]

Why not a series of Harbor Freight water pumps running full tilt, increasing emissions output to the point of sea level rise to push the water uphill for us? If we're going to e-vehicles soon, we need to burn all that gasoline somehow.

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

 

[SFCharlie]

Edit2: I know put Engineers in charge of everything!

Now, who with the authority to do so, would consider it for more that 7 microseconds?

SF Charlie
Eng-Tips.com Forum Policies

 

[Demented]

*spins in circles until he pukes*