Miami Beach, Champlain Towers South apartment building collapse, Part 19 27

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13
Miami Beach, Champlain Towers South apartment building collapse, Part 14
Miami Beach, Champlain Towers South apartment building collapse, Part 15
Miami Beach, Champlain Towers South apartment building collapse, Part 16
Miami Beach, Champlain Towers South apartment building collapse, Part 17
Miami Beach, Champlain Towers South apartment building collapse, Part 18

 

[SFCharlie]

nist-provides-update-champlain-towers-south-investigation

SF Charlie
Eng-Tips.com Forum Policies

 

[Oops409]

While is it great they may be doing the most significant building collapse investigation in history, it is also a classic Government Project that has a life of its own, as long as the government money keeps flowing their way.

In the government it is "USE or LOOSE" as far as obligating funds. Once funds obligated under a contract, they do not expire annually or semi annually if not spent within that time period.... So you slip schedule and do more work, if you have remaining funds......

Report will be concluded once the funding drys up.....

 

[Sym P. le]

Work continues ... to develop science-based recommendations

I don't know if this qualifies as science-based, but I recommend that if the elevated parking is cracked all to pieces, stop driving on it.

 

[1503-44]

Considering that we are talking about two of the most widely used construction materials in the entire world and the risk to life and property that amounts to nearly uncalculable value in Florida alone, I don't think that the importance of this investigation can be over emphisized. The so far resulting laws enacted requiring inspection, evaluation and repair of all condos in FL, not to mention the newly mandated financial responsibilities placed on the condo home owners associations have apparently killed the real estate market in Florida. You Tube is currently full of videos claiming that 80% of Florida condos are currently preceived as, if not actually, worthless, with hundreds of owners now facing impossible repair and future maintenance fund assessments, foreclosure and bankruptcy. I am not sure it is entirely true, as I don't live there and have no first hand sources of info, but that has already been commented above and it is filling all FL YT video streams at the moment, with claims of average value destruction of 40 to 60% of their buildings worth, with many tagged for evacuation and demolition. No mention of either hurricanes or shark attacks whatsoever. Such high devaluations of what appears to be the greater part of condos in FL, must certainly dwarf Boeing's problem. These must total trillions. So it seems imperative that a much greater understanding of this problem has to be achieved and my guess would be that the dollar spent to knowledge gained ratio could be one of the highest of any government funded study ever made. Since the potential impact on design, building codes and construction using the two most common materials in the industry used to build virtually everything on the planet could be astronomical, we probably need this one to play out.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Sym P. le]

Except that many of the issues are well known and plainly in front of us; poor design and execution of rebar, seperable structural risk zones, financial strategies pertaining to maintenance or market conditions.

 

[Oops409]

Except that many of the issues are well known and plainly in front of us; poor design and execution of rebar, seperable structural risk zones, financial strategies pertaining to maintenance or market conditions.

I agree many of the issues are well known, and not really in scope of NIST's scientific analysis of materials standardization testing from the remaining fragments, to determine as designed vs as aged strength.

When design and execution does even meet code at the time, it is impossible to access whether the structure would still be standing, if properly designed, constructed, and maintained. Then throw in the patio alterations that added additional loads and water management.

Frequently Government Studies are mostly a Jobs Program, and don't yield good bang for the buck......

Perhaps some additional information and change will be a result of NIST study, but all the quick changes implemented to Florida code, were not the result of NIST study output, which has now slipped to 2026 at the earliest.

 

[1503-44]

First, There are plenty of studies that I would much prefer to see abandoned other than this one. I'm sure you all can think of many such examples of those. However I am not one to make generic complaints about government studies when there is hope that one in particular could help me do my job. I support all that further the quest for engineering knowledge. I started out as a registered structural engineer, so perhaps I have more interest in this than mechanical engineers do, not that I would oppose gov studies into any area of engineering interest based on a generally perceived claim that they are all a waste of time and taxpayer money. Please note that this is the longest running discussion ever appearing on Eng Tips in the almost 20yrs I've been here, continued 18 times, so engineering interest in this topic is difficult to deny.

If issues were well known, but not adequately addressed, then isn't it all the more Important to confirm exactly what was not addressed and make sure that is well addressed in codes and regulations in future. Design, or aging. Its both. If you don't design for the future, it's a fail. Only a matter of time.

The Florida laws apparently address a multitude of issues and certainly were made in a kneejerk response, nonetheless this knowledge will probably aid in identifying what immediate changes need to be made that prioritize safety and which can wait while owners, tenners and builders sort out their own particular interests and responsibilities.



--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[3DDave]

Some want to de-fund government and vent at any opportunity.

 

[1503-44]

So it seems. Not that there isn't opportunity, but are there no more "woke" studies. I hear those are the favorite targets.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Oops409]

Some want to de-fund government and vent at any opportunity.

So it seems. Not that there isn't opportunity, but are there no more "woke" studies. I hear those are the favorite targets.

This collapse was so much more than just a failure of not having adequate building standards/requirements, which is the mission of NIST. Sure standards/codes have improved since this design/build, such as punch shear requirements, and I am sure there is plenty of room for standards improvement thru better understanding of the material science and environment.

This disaster was a total systems/process failure by the government, developer, builder, EOR, Homeowner Association/Owners, construction next door, etc. according the the information available to date and results of litigation.

Example of Key Contributing Failures beyond materials standardization:

1. EOR inspects contractor's work as agent for municipality AND at same time is a paid customer of developer, which allows non-design compliant build.

2. Corruption between private industry and government officials.

3. Homeowner's Association/Owners/Maintenance/alteration Process Issues (engineers, contractors, management and inspection

4. 40 year certification EOR does not adequately and immediately address risk in patio/parking deck

So your hope is if NIST says do it, it will be properly implemented and enforced, rather than political knee jerks solutions, like we have seen implemented so far? NIST does not enforce compliance.

I am almost 7 decades old, and I have not, nor will I ever own any kind of condo unit where I don't own and control everything for the property, including the structure. I know human nature is to ignore the hidden and just do cosmetic repairs, because the average home/condo owner has NO idea the risk of buying into a high rise condo home on the beach in Florida....

If I can't afford to own a parcel of land and building out right on the beach then I don't buy on the beach! This way I am not locked up in a cell, by the majority of the homeowners who refuse or can not afford to ensure building is safe and structurally maintained.

The result was the primary contributors to collapse were never held accountable! Rather only those new small contributors with deep pockets were required to pay the total settlement. Pretty 'Woke' IMO.

 

[dik]

That pretty much sums it up, and a bunch of people died without anyone being accountable.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[1503-44]

Well that list says there is certainly lots to learn.
I'm happy to wait for the engineering part to be completed..

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[lexpatrie]

This collapse was so much more than just a failure of not having adequate building standards/requirements, which is the mission of NIST.

No. That isn't remotely the role of NIST.

 

[Oops409]

No. That isn't remotely the role of NIST.

What do you think is NIST's Official Mission?

While building collapse investigations appears totally outside NIST's Mission Statement; measurement science, standards and technology are what is stated in their Mission Statement.

Perhaps we are in full agreement, as my wording was ambiguous.

Mission
To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

"in ways that enhance economic security and improve our quality of life" is where is all gets fuzzy......

Link to NIST's Mission Statement

https://www.nist.gov/about-nist

 

[Roga50]

South Florida fake engineer signed off on inspections of many recent projects--how soon before another collapse?

https://www.local10.com/news/local/...neer-suspected-of-using-late-fathers-license/

 

[3DDave]

It does not appear any of the inspections were for structural requirements. The main question for the false PE sign-off was how much of the work was done by unlicensed electricians, unlicensed plumbers, and unlicensed mechanical contractors.

 

[lexpatrie]

NIST doesn't write building codes or develop the relevant technical standards (i.e. concrete and steel codes). That's how I'm reading....

This collapse was so much more than just a failure of not having adequate building standards/requirements, which is the mission of NIST.

Mind you I don't read mission statements generally, but from my experience with NIST, they do collapse investigations, probably paired with laboratory work on the strength of various components, and generally with OSHA, at least this corner of NIST, if they assist in developing technical standards that are referenced in the building code, I'm unaware of that role. I believe they did make recommendations to change the building code after the WTC 1, 2, and 7 collapse, and some of those changes were made, but the changes I'm specifically aware of regard the number of stairs in larger occupancy buildings (four now, versus three previously), not something structural, egress lighting, maybe stair width, etc.

I'm not going to go along with the building standards or the code requirements being inadequate, considering the columns being over-reinforced per the code at the time, (and the slab depth being too thin, unless they actually ran calculations on the slab depth and proved it met serviceability back when). If you want, the 1963 ACI 318 code can be looked at here, this is a 1979 era building, but I think the 1963 code serves reasonably well. Section 913 addresses maximum and minimum reinforcing percentages for columns, and Table 909(b) has the limits for slab depth to omit deflection checks (admittedly there's nothing in there for two-way slabs, which I consider this to be, but I think that's a bit of a "fielder's choice" in that it could be designed as a two-way slab and function as a one-way slab or vice versa, I don't know when the two way slab thickness table showed up, but it's after 1963, and it's in my 1993 softcover copy).

Competence? Lack of Care? Ethical lapses? Conflict of interest inspecting one's own design? Conflict of interest being paid to inspect work by one party (contractor, I presume, or the city? Does anybody know?) and design the work by another party (the developer)?

I'm not blaming the code, not yet at least, and surely not exclusively. At least part of this is more oversight, inspection, poor plan review (if any), and a lack of peer review (sounds a bit like the NIST/OSHA report on the FIU bridge collapse, and Harbour Cay). A misdiagnosis as to the severity of the problem circa 2000-2020 seems tenable as well.

A lack of robustness in the recertification language that at least tempts engineers to ignore life-safety and ignore the existing plans and focus solely on signs of weathering/distress and fixate maniacally on windows and doors and electrical wiring, and ignore wind loading (since it wasn't even mentioned) of the building. (you need the internet archive to see the 'at the time" language, they've revised it.

Current (November 18, 2021):

https://www.miamidade.gov/permits/library/structural-recertification.pdf

November 2, 2013 copy:

Wayback Machine

You can compare the language using Draftable, PDF24 or I love PDF, if you wish, but the bit about wind load was added recently, previously they got excited about windblown gravel, but not the global LFRS, and also waived dead and live loads as a concern because they were "time tested".



I'll grant that the ACI 318 punching shear provisions have changed over the years (See Giduquio, Cheng, Dlamini, Reexamination Of Punching Shear Strength And Deformation Capacity Of Corner Slab-Column Connection, December 2017, for a reasonably thorough historical treatment), if that's where you're going with that comment, but I'm not convinced that can be laid at the feet of NIST the way your comment seems to suggest it can, that research didn't come from NIST and the original research wasn't from NIST, either, that I know of.

You could argue that the over-reinforced columns (i.e. too small and/or too much reinforcing steel, reported by the Miami Herald, Jan 21, 2022) are a pretty obvious issue that a peer review in the 1980s should have/would have caught (that the newspaper experts seized on it early on pretty much supports that claim), and also particularly in light of Harbour Cay having the same flaw (columns too small in cross section for the vertical rebar, slabs "too thin"), a review at the time should have caught it, but it's not clear that the over-reinforced columns exactly led to the collapse here, given they worked for 40 or so years, and a lot of attention is being paid to the horizontal bars and punching shear as initiating the collapse. Now, excess vertical reinforcement for the cross-section would complicate the horizontal bar placement (as was seen at Harbour Cay), but we've not seen any evidence that there were large voids in the column-slab joint a la Harbour Cay, which, incidentally, collapsed during construction.

Also (seemingly) in common with Harbour Cay (that I don't recall being brought up in the reporting), is the slab depth that is "too thin" (in the obvious sense of too thin to omit the checks for deflection, rather than meaning there's a blatant punching shear deficiency). The slab being "too thin" to omit the deflection check would make a punching shear issue more likely, but a thin slab doesn't guarantee a punching shear issue, or a collapse, or an issue, even, and enlarging the columns (again, they were too small for the reinforcement on some levels even per the 1963 code), increases the perimeter of the column and increases the punching shear strength per the 1963 codes, et. seq.).

You can also extend the stronger column concrete out from the column into the slab to increase punching shear strength that way, as well., and there were (depending on the floor) concrete column strengths higher than the slab strength.

There is also a limit on column versus slab strength that wasn't respected on at least one level (See section 917 in the 1963 code, also apparently not flagged by anybody in the reporting, though maybe that was deemed too complex for the newspaper reporting and got cut). There are ways of dealing with that issue that might not be in the drawings (I'd rule out option 3 since there are relatively few beams in the building). It's possible that sort of puddling of column concrete around the column-slab joint was implicit or standard practice at the time, and thus not noted on the drawings, or it was a field memo or something. It was already an option in the concrete code for say, 15 years.

Of course, now that I look at it, Harbour Cay collapsed March 27, 1981, the NIST report came out September 1981, and the CTS plumbing plan (it's what I have written down) is dated August 13, 1979 (two years before Harbour Cay collapsed). For all we know, the Harbour Cay people could have gone to CTS and gotten inspiration that their columns were fine because another comparison structure used similarly sized columns. But that undermines the whole "peer review should have caught this" at least some. I don't have the permit date or start/end of construction date for Champlain Towers South.

I won't hang Harbour Cay on the CTS designer. It's established that the Harbour Cay design engineers were quite new to concrete construction and designed a building quite beyond their depth. There are, however, similar potential flaws on both buildings.