Miami Beach, Champlain Towers South apartment building collapse, Part 02 151

Well, as bad as the collapse is, it is possible we can learn something from this collapse.There are an awful lot of similar buildings in florida, as well as other seaside communities.

Perhaps there should be mandated an annual survey of building foundation movement using laser technology , with results reported to county authorities and immediately available to building residents, investors, and insurance companies. It would seem that the insurance companies would be the first to push for such legislation. Certainly any investor in buying such an aged unit would require a detailed structural analysis before such a purchase, but it is also prudent to provide the individual condo residents to have timely access to such information, thus the annual laser scans. The negative side of such an approach is that there will occur a step change decrease in the value of some units.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

If MY life were on the line, I would prefer those window-washing anchors to have another steel plate on the BACK of the column. Probably even skip the epoxy and use a smaller hole.



spsalso

Structural guys live dangerously... without doing any calcs, the anchorage is more than adequate for the 5K load, assuming the backing material is sound.

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

-Dik

Not relevant, but the poster of the twin towers in this bedroom made me pause.

I've never seen failures with rebar like that... looks like it just 'unzipped'.

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

-Dik

Quote:
RickyTickyTavi (Structural)28 Jun 21 14:16
2. Roof Anchors/Fall arrest system installation. If this was a post-tensioned building and the contractor repeatedly knocked out tendons with drilling operations, I could see this being plausible. But other than localized damaged/deterioration around the anchors, they are rather non-obtrusive in the short term. One minor comment on that design, I'm sort of surprised the original engineer went with a 2 anchor design - I had assumed the 4 anchor OSHA minimum would apply to fall arrest systems.

Should not be an issue.

Thanks for starting the new thread.
Thanks for the URL.


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SteveWag (Civil/Environmental)28 Jun 21 03:30 said:

three area drains

Click to expand...

reminded me of this interview...
Condo Collapse: Former Maintenance Staff Manager Was Concerned About Saltwater Intrusion


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"Jason Borden, a structural engineer whose firm had conducted an hour-long site survey of the building in 2020, said what he observed "was typical of a 40-year old building that had had some deferred maintenance." That means that parts of the building had reached their "expected useful life" and needed to be repaired or replaced, but added that his team did not see anything out of the ordinary, and certainly nothing potentially catastrophic."

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

-Dik

IMO, that was a little EARLY to close the opening discussion.

Please read through at least the last 20% of the original thread and all of below to get an idea of the current state of the discussion.

I have several comments to make, but I have to leave for an appointment. Here is a start:

(1) Columns were not designed for penthouse loads
(2) Deck level; water damage; waterproofing damaged -- who should have alerted condo association to the level deck problem? When? Should the 1981 building inspector have required sloping to drains?
(3) Should columns be required to be safe even after losing 1 or 2 lateral supports in buildings with more than, say, 30 bedrooms (60 people)?
(4) Real estate agents get 6% every time one of these units changes hands, and how often does the condo association pay 6% of the buildings value for a full structural review?

My heart is beating just watching these videos and reading reports! Adrenalin in action as the situation is so frightening!

TugboatEng said:

They needed an earthquake to undo some of that subsidence.

Click to expand...

The "quake" was not a natural one and was too far off shore (over 100 miles away from the hypocenter (shallow underground explosion). Both P and S waves would have lost much of their energy long before arriving at the site of the condo. M3.9 packs a good amount of energy at the hypocentral source and normally only felt in dozen miles or so around it (depending on the medium through which they travel.).

Oceanic crust in that area is likely brittle basalt which can deaden the propagation of the wave energy.

That region near the condo, at that distance from the quake is not likely to be all that impacted, if at all. I would say, the "quake" was not a factor.

It went on longer than it should have... a new thread should have started after about 200 or 250 replies, not 350...

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

-Dik

Back in 2010, there was a 5.0 in Toronto. The only way I knew it was happening about 60 miles away in Buffalo, was my monitor wiggled for a few seconds. It was otherwise not perceptible to me.

Edit: This was actually much closer to Ottawa than TO, closer to a 250 miles from TO and 300 miles from Buffalo

I didn't know it was a 5, but was there and you could feel the shaking 'through your feet'.

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

-Dik

Just something to add. A sat image of the pool/spa area. In my college days I was a pool tech. Often times the pump rooms for these systems would be under the deck. I would hazard to guess that the pump room was in the same space as the underground parking garage. These systems often have leaks and poor ventilation. While it may be a small factor, chlorine vapor in a humid environment can be highly corrosive to metal. As long as the pool was staying clean and the water parameters were correct there would have been little reason to go into the pump room. So its possible chlorine vapor could have worked its way into the exposed metal and drastically sped up rate of corrosion.
Just a thought.

One guy does admit parking in garage around 1am before collapse, but then leaving with a scooter. Claims his power was out in his apartment. No evidence that his car bumped into any columns though.

and...
"The Champlain Towers South condo building collapse began in the bottom of the building and brought the rest of it down with it in a 'domino effect collapse', experts said on Monday as questions grew over why repairs weren't done when the damage was identified three years ago by an engineer who inspected the property and found 'significant' cracks in the concrete columns in the parking garage.

Officials won't yet comment on what exactly brought the 40-year-old tower down but experts who have viewed footage of it say it started with a problem in the bottom of the building - perhaps the parking garage - and once that crumbled, huge swathes of the building came down with it.

Some experts say it could have been the result of eroded columns collapsing under the weight the building. The cause of the erosion could have been spalling, which occurs when salt air gets into the column and rusts the steel inside.

Frank Morabito identified spalling in the columns in the Champlain Towers South parking garage in a 2018 report. He also found damage elsewhere and recommended $12million worth of repairs but nothing was done to until this year, when the condo association board planned to overhaul the property to meet its 40-year recertification requirements.

Morabito broke his silence on Monday to release a statement saying he recommended the changes three years ago to the condo association - a board of seven volunteers, five of whom were living in the building and one of whom remains missing."

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

-Dik

Here's a clear photo of a non-involved column for what it's worth.