Condo wreckage hints at less steel in columns than design drawings(nytimes.com)
nytimes.com
Condo wreckage hints at less steel in columns than design drawings
https://www.nytimes.com/2021/07/03/us/florida-condo-collapse-steel-rebar.html
113 comments
It's not that rare, I see it several times a year.
It is presumed that all foundation bolts are shot after about 50 years on any foundation in terms of their seismic performance. If you pull out an old foundation from say the 1950s, the bolts are almost invariably either totally corroded through or just a thread in the middle.
For a building basically sitting in saltwater, I would expect there to be widespread reinforcing steel failure at that age without proof to the contrary. Which is certainly one of the big reasons why they require recertification, although obviously the 40 year recertification schedule has proven to be woefully inadequate.
This will probably not wind up being more interesting than a failure to have rigorous enough inspection schedules and people dragging their feet to do what obviously had to happen. Those items appear far more important that the somewhat reduced amount of reinforcing steel compared to drawings at this point. It seems like relatively pedestrian negligence.
It is presumed that all foundation bolts are shot after about 50 years on any foundation in terms of their seismic performance. If you pull out an old foundation from say the 1950s, the bolts are almost invariably either totally corroded through or just a thread in the middle.
For a building basically sitting in saltwater, I would expect there to be widespread reinforcing steel failure at that age without proof to the contrary. Which is certainly one of the big reasons why they require recertification, although obviously the 40 year recertification schedule has proven to be woefully inadequate.
This will probably not wind up being more interesting than a failure to have rigorous enough inspection schedules and people dragging their feet to do what obviously had to happen. Those items appear far more important that the somewhat reduced amount of reinforcing steel compared to drawings at this point. It seems like relatively pedestrian negligence.
Similar to the Grenfell Tower fire in Uk, where over 70 people burned alive. The residents warned that the building was unsafe, fire inspector warned it was unsafe, yet nothong was done. Now investigation is 4 years in and it has been an endless processions of code violations, cost cutting, lost building plans (the company told the court that intern deleted them) and outright fraud by the company that produced cladding to mark it as firesafe when it wasn't.
This prompted a review of many building across UK, and lo and behold, thousand or so buildings in UK have massive structural and fire safety defficiencies. Remediation works go anywhere from 25%-75% of original property cost.
The best part is, the builders are not on the hook, the building owner is not on the hook, the management company is not liable, but a leaseholder that bought 25% of the apartment is responsible for 100% of the bill to put things right. Those properties are unsellable, and have become a toxic asset.
This prompted a review of many building across UK, and lo and behold, thousand or so buildings in UK have massive structural and fire safety defficiencies. Remediation works go anywhere from 25%-75% of original property cost.
The best part is, the builders are not on the hook, the building owner is not on the hook, the management company is not liable, but a leaseholder that bought 25% of the apartment is responsible for 100% of the bill to put things right. Those properties are unsellable, and have become a toxic asset.
> lost building plans
That's pretty wild. I thought city halls had copies of all building plans from when they were submitted for permit approval.
That's pretty wild. I thought city halls had copies of all building plans from when they were submitted for permit approval.
In the UK the local council (town hall) only holds the plans relevant to making planning decisions, not the detailed construction plans. Private companies can sign off the building safety (known as building control) usually as part of providing a new build warranty on the development (but then one of the biggest providers, Zurich, offloaded their portfolio to a shell company than then went bankrupt under the liabilities due to incorrectly signing off buildings. The whole situation is a major scandal in the UK at that moment)
"Similar to the Grenfell Tower fire in Uk"
No it isn't quite the same. I recently had a look at the docs about Grenfell. That's here: https://www.gov.uk/guidance/aluminium-composite-material-cla...
I haven't quite got to the bottom of whether the standards relating to fire was broken or whether the guidance for builders had a hole in it that allowed for what we now know as sub standard cladding.
No it isn't quite the same. I recently had a look at the docs about Grenfell. That's here: https://www.gov.uk/guidance/aluminium-composite-material-cla...
I haven't quite got to the bottom of whether the standards relating to fire was broken or whether the guidance for builders had a hole in it that allowed for what we now know as sub standard cladding.
The unquiry is still ongoing, but firstly the fire safety ceritifucate was forged, as second its not just the cladding, there were missing firebreaks, no evacuation route for disabled people, not functioning fire alarms and smoke extraction and countless other issues in the bulding - if it was just cladding half the residents wouldn't have coocked alive
https://www.insidehousing.co.uk/news/news/grenfell-contracto...
https://www.insidehousing.co.uk/news/news/grenfell-contracto...
My point was about whether the standards themselves were wrong.
You mention that the fire safety cert. was forged, they missed out firebreaks and there was a lack of escape routes. Also inadequate alarms and several other failings.
That is "just" crass negligence (dangerous and as it turns out massively fatal, negligence)
My point is that there also seems to be a possible systemic failure. There seem to be a few document releases since the disaster, of updates to standards. That implies that the standards themselves were inadequate and that is also a problem.
You mention that the fire safety cert. was forged, they missed out firebreaks and there was a lack of escape routes. Also inadequate alarms and several other failings.
That is "just" crass negligence (dangerous and as it turns out massively fatal, negligence)
My point is that there also seems to be a possible systemic failure. There seem to be a few document releases since the disaster, of updates to standards. That implies that the standards themselves were inadequate and that is also a problem.
> The best part is, the builders are not on the hook, the building owner is not on the hook, the management company is not liable, but a leaseholder that bought 25% of the apartment is responsible for 100% of the bill to put things right. Those properties are unsellable, and have become a toxic asset.
Not insurers? Or the owners aren’t required to carry insurance?
Not insurers? Or the owners aren’t required to carry insurance?
Saw a video today of a simulated collapse that suggests a possible failure mode given the likely parking garage collapse that occurred before primary collapse:
https://www.youtube.com/watch?v=hynHiWE818c
https://www.youtube.com/watch?v=hynHiWE818c
That's an interesting theory that I hadn't seen before. It would require the horizontal rebar in the pool deck to be strong enough that it could pull over the columns, which contrasts with that rebar also being weak enough to collapse. Likewise, in this scenario, would there still be punch-through columns in the parking deck area, instead of those columns falling over too?
The other question that obviously follows from this is, were those columns to fail, why did the failure of the columns on one edge of the building cause the entire section of building to collapse catastrophically? At 1:08 of the simulation, you can see the rest of the columns are still standing under the building.
The other question that obviously follows from this is, were those columns to fail, why did the failure of the columns on one edge of the building cause the entire section of building to collapse catastrophically? At 1:08 of the simulation, you can see the rest of the columns are still standing under the building.
Steel is strongest in extension, and a horizontal pulling moment is going through the cross section of the rebar rather then perpendicular to it.
The rebar would have different load bearing capacities in different directions, particularly if it was rusting (i.e. most likely the corrosion was principally on the top face).
The rebar would have different load bearing capacities in different directions, particularly if it was rusting (i.e. most likely the corrosion was principally on the top face).
Fwiw: there's a video circulating social media showing what appears to be rubble in the parking garage, claimed to be taken a few minutes before the tower collapse.
This is an interesting theory... one would wonder, how come it collapsed at the place, where it only held one slab, and not somewhere under more weight... but i'm not a civil engineer, so yeah... time (and analysis) will tell.
That area, the pool deck, was exposed to the elements. Rainwater was allowed to pool on top and seep into the concrete because it was not constructed correctly. It should have been slanted to allow water to drain off.
The slabs and pillars under the actual building may have been in better condition since they were mostly protected from the weather.
In salty environments, exposure to the weather tends to allow rain to wash away salt. Semi- exposed areas tend to fair worse for corrosion due to the absence of scouring by rain.
A bit counter intuitive.
But that’s building by the sea. Salt can be deposited by mist and chloride ions are the nemesis of reinforced concrete.
A bit counter intuitive.
But that’s building by the sea. Salt can be deposited by mist and chloride ions are the nemesis of reinforced concrete.
Also, once the initial shift occurred, could that have caused enough plumbing to break to begin flooding and further cause solid ground to liquify?
This would also be consistent with less steel being included than originally designed, as was rumored during construction of numerous hi-rises during the boom.
Looks almost like punch-through of all floors simultaneously due to shock, almost as if it was a planned demolition where stuctural supports are compromised with precision to assure orderly collapse.
Only this part of the building fell precisely without any carefuly placed dynamite.
But when buildings are stronger, sometimes intentional demolition projects do not complete the job so thoroughly on the first attempt.
Looks almost like punch-through of all floors simultaneously due to shock, almost as if it was a planned demolition where stuctural supports are compromised with precision to assure orderly collapse.
Only this part of the building fell precisely without any carefuly placed dynamite.
But when buildings are stronger, sometimes intentional demolition projects do not complete the job so thoroughly on the first attempt.
> Mr. Kilsheimer cautioned that it is common in construction for the final product to differ from drawn designs.
Yes, and there's also a decent history of structural failure, or nearly so, from that particular habit.
The Hyatt walkway collapse (https://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse...) is one of the better known - designed one way, built another so it would be easier and cheaper to build, and nobody thought through the changes in terms of how it impacted loading. Result? 114 dead.
The I-35 bridge collapse was another case of "various safety factors were eliminated until the safety factor was less than one." https://en.wikipedia.org/wiki/I-35W_Mississippi_River_bridge...
> On November 13, 2008, the NTSB released the findings of its investigation. The primary cause of the collapse was the undersized gusset plates, at 0.5 inches (13 mm) thick. Contributing to that design or construction error was the fact that 2 inches (51 mm) of concrete had been added to the road surface over the years, increasing the static load by 20%. Another factor was the extraordinary weight of construction equipment and material resting on the bridge just above its weakest point at the time of the collapse. That load was estimated at 578,000 pounds (262 tonnes), consisting of sand, water and vehicles. The NTSB determined that corrosion was not a significant contributor, but that inspectors did not routinely check that safety features were functional.[126]
There's a lot of redundancy built into modern construction, but if you remove some of it because it's cheaper to build, and other degrades over time from wear, well... at some point, there's nothing left.
It's going to be an interesting report to read, whatever the causes.
Yes, and there's also a decent history of structural failure, or nearly so, from that particular habit.
The Hyatt walkway collapse (https://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse...) is one of the better known - designed one way, built another so it would be easier and cheaper to build, and nobody thought through the changes in terms of how it impacted loading. Result? 114 dead.
The I-35 bridge collapse was another case of "various safety factors were eliminated until the safety factor was less than one." https://en.wikipedia.org/wiki/I-35W_Mississippi_River_bridge...
> On November 13, 2008, the NTSB released the findings of its investigation. The primary cause of the collapse was the undersized gusset plates, at 0.5 inches (13 mm) thick. Contributing to that design or construction error was the fact that 2 inches (51 mm) of concrete had been added to the road surface over the years, increasing the static load by 20%. Another factor was the extraordinary weight of construction equipment and material resting on the bridge just above its weakest point at the time of the collapse. That load was estimated at 578,000 pounds (262 tonnes), consisting of sand, water and vehicles. The NTSB determined that corrosion was not a significant contributor, but that inspectors did not routinely check that safety features were functional.[126]
There's a lot of redundancy built into modern construction, but if you remove some of it because it's cheaper to build, and other degrades over time from wear, well... at some point, there's nothing left.
It's going to be an interesting report to read, whatever the causes.
The Hyatt walkway collapse could be interpreted as you said, but I think the specific phrasing ("built another so it would be easier and cheaper to build") shifts the blame onto suppliers and manufacturers a bit too much. The wiki article states that the architectural/engineering firm signed off on the suggestion of their supplier/manufacturer. While yes, it's easy to point the finger at cost cutting, we should also remember the point of engineering. It's to problem solve under constraints, and saving cost is absolutely a valid constraint. It's also worth noting that the original, unmodified design was already under-strength (relative to code).
For I-35, the NTSB report indicates that the design itself was undersized.
Designs need to be be accommodate for imperfect (and sometimes somewhat negligent) manufacturing, but these two examples aren't the best given the relative impact of flawed design, or design/change control process.
For I-35, the NTSB report indicates that the design itself was undersized.
Designs need to be be accommodate for imperfect (and sometimes somewhat negligent) manufacturing, but these two examples aren't the best given the relative impact of flawed design, or design/change control process.
Can you come up with some examples that you’d grade well?
Not really off the top of my head, especially in North America.
I suspect you if you really go through (https://www.osha.gov/construction/engineering) you'll find some good examples of construction time problems. By it's nature, the vast majority of these are going to be "during construction time", so it'll be biased. They're also typically smaller scale operations... but that's also reflective of reality. Most construction is not the scale of 100+ unit condo buildings.
From my skimming through it there's a pretty even mix of:
a) Designer dominant (note there are a significant number of so called "design-build" entities present as well).
b) Construction/contractor supervisor/company dominant
c) Construction/contractor crew on the ground dominant
The NTSB also has a set of building related investigations to read through. Unfortunately, I seem to be having problems figuring out their search.
I suspect you if you really go through (https://www.osha.gov/construction/engineering) you'll find some good examples of construction time problems. By it's nature, the vast majority of these are going to be "during construction time", so it'll be biased. They're also typically smaller scale operations... but that's also reflective of reality. Most construction is not the scale of 100+ unit condo buildings.
From my skimming through it there's a pretty even mix of:
a) Designer dominant (note there are a significant number of so called "design-build" entities present as well).
b) Construction/contractor supervisor/company dominant
c) Construction/contractor crew on the ground dominant
The NTSB also has a set of building related investigations to read through. Unfortunately, I seem to be having problems figuring out their search.
Reminded me of this /r/tfts post.
https://www.reddit.com/r/talesfromtechsupport/comments/5s9mr...
https://www.reddit.com/r/talesfromtechsupport/comments/5s9mr...
This sounds similar to the Toronto stage collapse that happened. The design spec'd out 3" tubing, but such a thing didn't "exist" (in their inventory) and they used 2".
https://www.cbc.ca/news/canada/toronto/radiohead-stage-colla...
https://www.cbc.ca/news/canada/toronto/radiohead-stage-colla...
Don't forget the Challenger SRB failure. Flown outside of design criteria with known flaws. But each time the shuttle flew with and SRBs had burn through, it was taken to mean not that there was a problem, but that the behavior was "safe".
Normalisation of Deviance.
https://en.wikipedia.org/wiki/Normalization_of_deviance
See Charles Perrow's Normal Accidents and The Next Disaster.
https://en.wikipedia.org/wiki/Charles_Perrow
https://en.wikipedia.org/wiki/Normalization_of_deviance
See Charles Perrow's Normal Accidents and The Next Disaster.
https://en.wikipedia.org/wiki/Charles_Perrow
That's the idea. The exact formulation of the term had slipped my mind.
Right.
Knowing the extant nomenclature is useful in researching ideas / literature further. I'm often stymied because I don't know what things are called in certain domains. Psychology seems to be especially prone to this for me.
Knowing the extant nomenclature is useful in researching ideas / literature further. I'm often stymied because I don't know what things are called in certain domains. Psychology seems to be especially prone to this for me.
If the Hyatt walkway had been built as it was designed, I'm sure it would have worked fine. But was it realistic to build it as designed? The design called for something like 12 meters (12m is my estimate from it needing to span the 2nd to 4th floor) of continuously threaded rod. Is cutting 12 meters of continuous thread on one rod a realistic design? This is a real question, I don't know the answer but this seems suspect to me. Wikipedia says the reason the construction company changed the design is because they would have to screw the bolts past several meters of thread per rod and they thought such long sections of threading would be subject to damage during construction.
Obviously their "solution" was lethal. But the original presumably safe design seems impractical at best.
Obviously their "solution" was lethal. But the original presumably safe design seems impractical at best.
The original design was bad in several ways.
> Analysis of these two details revealed that the original design of the rod hanger connection would have supported 90 kN, only 60% of the 151 kN required by the Kansas City building code. Even if the details had not been modified the rod hanger connection would have violated building standards. As-built, however, the connection only supported 30% of the minimum load which explains why the walkways collapsed well below maximum load (Feld and Carper, 1997).
(my emphasis)
http://anengineersaspect.blogspot.com/2009/07/the-28th-anniv...
> Analysis of these two details revealed that the original design of the rod hanger connection would have supported 90 kN, only 60% of the 151 kN required by the Kansas City building code. Even if the details had not been modified the rod hanger connection would have violated building standards. As-built, however, the connection only supported 30% of the minimum load which explains why the walkways collapsed well below maximum load (Feld and Carper, 1997).
(my emphasis)
http://anengineersaspect.blogspot.com/2009/07/the-28th-anniv...
Excellent information, I never heard this before. Thank you.
It is possible to cut a single thread 12 meters long, but it would be hard to position on the construction site.
I worked in a gear shop for 5 years, yes, threads that long can be done. I suspect it might have been cheaper to get a rolled thread in that length, rather than a cut thread. Rolled thread is likely to be stronger, as it is formed, and not cut.
I worked in a gear shop for 5 years, yes, threads that long can be done. I suspect it might have been cheaper to get a rolled thread in that length, rather than a cut thread. Rolled thread is likely to be stronger, as it is formed, and not cut.
Screw threads are incredibly strong. From memory, small (M3) standard screws with common materials are rated for several kN of load.
The Hyatt Walkway collapse was a failure of communications, the problems actually building it as designed, and the importance of building as it was designed, weren't properly communicated. If anyone had the whole picture, and realized what had happened, it would have been fixed at construction time.
Also interesting is the Citigroup Center building in NYC that almost suffered a catastrophic failure after construction completed in 1977.
> Due to material changes during construction, the building as initially completed was structurally unsound.
> Due to material changes during construction, the building as initially completed was structurally unsound.
I read this and i think about the builder who ADDED rebar to Falling Water's cantilevered concrete. Wright was pissed, but I understand it's the only reason it's still standing today.
I'm not a fan of the "Hyatt walkway collapse" as a teaching tool. The mathematics is extra interesting. Not sure it's good for the design failure which people reference. More people die from bad insulation design each year, it's the boring stuff that matters.
The Hyatt walkway collapse was at a big dance party with a fair few people watching from above. Perhaps dancing?
I-35 bridge collapse was rush hour.
What's the peak here? Why 1am?
The Hyatt walkway collapse was at a big dance party with a fair few people watching from above. Perhaps dancing?
I-35 bridge collapse was rush hour.
What's the peak here? Why 1am?
> What's the peak here? Why 1am?
I wondered this too. Maybe contraction or rate of contraction?
Sun has gone down, outdoor temperature is dropping, max heat radiation out if the sky is clear, and everybody is home so A/C is on in all units.
I wondered this too. Maybe contraction or rate of contraction?
Sun has gone down, outdoor temperature is dropping, max heat radiation out if the sky is clear, and everybody is home so A/C is on in all units.
The coldest is a bit after dawn. So the previous dawns should have stress tested it. It should fail when the stress is around maximum under this Hyatt peak theory.
Max rate of change of temperature is sunset and sunrise. Rate of contraction I'd expect similar?
I'm not sure AC would change the thermal mass of a building much. One cubic meter of air weights 1.2kg. Changing the concrete walls would be hard.
A drunk hitting a pole at speed in the carpark would fit perhaps. Drunkenness to an empty carpark would be high.
Max rate of change of temperature is sunset and sunrise. Rate of contraction I'd expect similar?
I'm not sure AC would change the thermal mass of a building much. One cubic meter of air weights 1.2kg. Changing the concrete walls would be hard.
A drunk hitting a pole at speed in the carpark would fit perhaps. Drunkenness to an empty carpark would be high.
> The coldest is a bit after dawn.
The building (and deck surface) will continue to radiate heat throughout the night on a clear night, especially with few obstructions like a waterfront building has. That's how crops can frost with airtemp > freezing, and why the guidance is to cover your plants. It's not to insulate them against convection.
Counterintuitively in this scenario, this effect is greatest when the wind is calm.
https://en.wikipedia.org/wiki/Radiative_cooling#Architecture
The building (and deck surface) will continue to radiate heat throughout the night on a clear night, especially with few obstructions like a waterfront building has. That's how crops can frost with airtemp > freezing, and why the guidance is to cover your plants. It's not to insulate them against convection.
Counterintuitively in this scenario, this effect is greatest when the wind is calm.
https://en.wikipedia.org/wiki/Radiative_cooling#Architecture
If the peak was actually a trigger, in a residential building 1am is about the start when the max people other than a party will be there (everyone back from clubs)
It's also approximately the time when the building will be coldest. If there were any thermal expansion/contraction issues, they would have been at a maximum near 1am. The thermal expansion and contraction of concrete and reinforcing steel are nearly identical, but the steel has much higher thermal conductivity and cools off far faster; perhaps something snapped under tension between concrete that was still holding heat from the setting sun and steel that had shrunk in the chill of the night.
Incidentally, that chill is also why the 'low battery' alarms on smoke detectors tend to vexingly wake you up in the middle of the night, rather than conveniently running out in the 16 hours a day you're awake, which you might expect to happen twice as often. No, it's not just a bias that causes you to remember waking up to smoke alarm low battery chirps but not hearing them in the daytime, the electrochemical reaction in the batteries happens more readily at higher temperatures. It's a different chemistry, but the same reason a lead acid car battery has a hard time turning a starter in the dead of winter. The sensors in the smoke alarm always draw the same few microamps of current, but when it's coldest in the middle of the night, the battery is less able to meet the demand, and wakes you from your sleep.
Incidentally, that chill is also why the 'low battery' alarms on smoke detectors tend to vexingly wake you up in the middle of the night, rather than conveniently running out in the 16 hours a day you're awake, which you might expect to happen twice as often. No, it's not just a bias that causes you to remember waking up to smoke alarm low battery chirps but not hearing them in the daytime, the electrochemical reaction in the batteries happens more readily at higher temperatures. It's a different chemistry, but the same reason a lead acid car battery has a hard time turning a starter in the dead of winter. The sensors in the smoke alarm always draw the same few microamps of current, but when it's coldest in the middle of the night, the battery is less able to meet the demand, and wakes you from your sleep.
Wouldn’t the coldest part of the night typically be immediately before sunrise?
All it takes is being cold enough to cause the extra voltage drop.
The 1978 Citigroup Center engineering crisis is a good teaching tool. The chair of my Uni's Mechanical Engineering department has gotten a good amount of engineering colleges (mainly Mechanical and Civil) to use it as an example/study for students first semester.
What did you learn from the Citigroup Center story?
For me a good story is when a friend built a house the design didn't fit the actual plot, so it was changed by the builders.
One of the final problems was an overhang on the upper roof went over the sky light.
Lessons -
Contrary to common beliefs land plots are not well known.
Engineers/Designers work off incomplete information.
Problems cascade to strange places.
For me a good story is when a friend built a house the design didn't fit the actual plot, so it was changed by the builders.
One of the final problems was an overhang on the upper roof went over the sky light.
Lessons -
Contrary to common beliefs land plots are not well known.
Engineers/Designers work off incomplete information.
Problems cascade to strange places.
Where I work an old building had massive plumbing problems for years-- flooded floors.
After it happened a few times someone went back to the original plans to see if it might reveal the cause. They were shocked to discover it specified & contracted to have copper pipes. The building had PVC instead. And engineering firm was brought in to make an assessment and determined that the PVC used wasn't even rated for the type of plumbing application necessary.
No one knew how it happened, how inspections could have signed off on the discrepancy. Everyone from that time was gone, and the construction company was a ghost. It's unclear if it was incompetent oversight that allowed the contracter to cut corners or something more "inside job" in nature.
After it happened a few times someone went back to the original plans to see if it might reveal the cause. They were shocked to discover it specified & contracted to have copper pipes. The building had PVC instead. And engineering firm was brought in to make an assessment and determined that the PVC used wasn't even rated for the type of plumbing application necessary.
No one knew how it happened, how inspections could have signed off on the discrepancy. Everyone from that time was gone, and the construction company was a ghost. It's unclear if it was incompetent oversight that allowed the contracter to cut corners or something more "inside job" in nature.
This is unfortunately very common. The building I live in is not that old (about 15 years. I moved in 10 years ago).
We have the original plans, which were somehow never registered with the city (which has been part of the permitting process for buildings of this size since long before it was built). The codes to the fire alarms were never registered with the fire department (also a requirement). A lot of extremely visible features, like stairways, are not up to code. Every time we fix, rebuild or renovate anything, we find the builders didn't just ignore the plans here and there: they may as well be plans for a different buildings. Nothing matches except the floor plan and the amount of units/stories.
Yet the permits are on file and were all signed on. Somehow when we try to get permits for anything, the processes are INCREDIBLY strict, stricter than in any other city I've lived by an order of magnitude. But somehow, for this building, there's very nearly more violations than there are things done kosher.
It's not an isolated incident either...that shit happens everywhere. Inspectors get paid, turn a blind eye, profit.
We have the original plans, which were somehow never registered with the city (which has been part of the permitting process for buildings of this size since long before it was built). The codes to the fire alarms were never registered with the fire department (also a requirement). A lot of extremely visible features, like stairways, are not up to code. Every time we fix, rebuild or renovate anything, we find the builders didn't just ignore the plans here and there: they may as well be plans for a different buildings. Nothing matches except the floor plan and the amount of units/stories.
Yet the permits are on file and were all signed on. Somehow when we try to get permits for anything, the processes are INCREDIBLY strict, stricter than in any other city I've lived by an order of magnitude. But somehow, for this building, there's very nearly more violations than there are things done kosher.
It's not an isolated incident either...that shit happens everywhere. Inspectors get paid, turn a blind eye, profit.
> It's not an isolated incident either...that shit happens everywhere. Inspectors get paid, turn a blind eye, profit
If something goes wrong, isn't the inspector who signed off liable? Maybe not for damages, but they'd certainly lose their credentials and job. Do they just hope it never happens while they're still at it?
If something goes wrong, isn't the inspector who signed off liable? Maybe not for damages, but they'd certainly lose their credentials and job. Do they just hope it never happens while they're still at it?
Only if someone can prove it was caused by something they should have caught. Good luck with that.
My William of Occam hat says most likely the Owner approved the change. Shaving money from the materials budget saved money.
So yes an inside job as inside as inside can be.
So yes an inside job as inside as inside can be.
Hard to say-- the owner was pretty damn pissed off about things too. Given what I saw if that, I could more easily imagine an underling dealing with cost overruns & agreeing to let the contractor go the cheap route.
I can also easily imagine that the cost overruns we're overstated and the contractor pocketed the extra profit.
I can also easily imagine that the cost overruns we're overstated and the contractor pocketed the extra profit.
It's not uncommon for Owners to be pissed off by their own cheaper-now decisions. The Owner and the Contractor spend all day on site talking about how stupid the Designers were...which is easy because all their mistakes are right there on paper.
Anyway, the Owner's underlings are the Owner if they have the authority to approve changes.
And if you saw the Owner pissed off, then it is not unlikely that they are the sort of person who blames others for their errors.
As for the distribution of the money, everyone probably got some except the Design team...it's the sort of change that the Owner and Contractor collaborate on despite the professional opinions of the Design team. And so the Design team can wash its hands of responsibility since they did not get paid for the extra work of changing the design (which is why the design documents differ from the asbuilts).
Or to put it another way, with any substantial size building everyone was sitting around the table when the option was discussed and the Design team walked the site prior to approving the Contractor's pay requests for plumbing labor and materials.
There are lots and lots of checks and balances in even below average construction projects. Swapping PVC for copper throughout is not the sort of thing that goes under the radar.
Anyway, the Owner's underlings are the Owner if they have the authority to approve changes.
And if you saw the Owner pissed off, then it is not unlikely that they are the sort of person who blames others for their errors.
As for the distribution of the money, everyone probably got some except the Design team...it's the sort of change that the Owner and Contractor collaborate on despite the professional opinions of the Design team. And so the Design team can wash its hands of responsibility since they did not get paid for the extra work of changing the design (which is why the design documents differ from the asbuilts).
Or to put it another way, with any substantial size building everyone was sitting around the table when the option was discussed and the Design team walked the site prior to approving the Contractor's pay requests for plumbing labor and materials.
There are lots and lots of checks and balances in even below average construction projects. Swapping PVC for copper throughout is not the sort of thing that goes under the radar.
There are lots of comments on HN over the years lamenting the cost of building infrastructure in the US, compared to China or elsewhere. I'm genuinely curious if this kind of corruption described in this article would be more or less common in China, or if this practice is rampant whenever you have construction projects anywhere in the world.
It doesn't seem to be all that uncommon to read about a building collapse, or fire, somewhere in the world. Invariably one learns about some kind of corruption in the process.
Fortunately the cases I know about haven't been life threatening, but there have been road construction projects in my town in the US, that had to be torn up and re-done at the contractor's expense because they missed some crucial specification such as the required thickness of the materials, and the roads started to crumble and buckle.
Fortunately the cases I know about haven't been life threatening, but there have been road construction projects in my town in the US, that had to be torn up and re-done at the contractor's expense because they missed some crucial specification such as the required thickness of the materials, and the roads started to crumble and buckle.
Is there a reason to jump to this was corruption, rather than a fuckup? When you look at the price of rebar per linear foot, this doesn't seem like the first place I'd look to cut costs.
A fuckup aggravated by what seems like not particularly aggressive maintenance of the structure generally.
A fuckup aggravated by what seems like not particularly aggressive maintenance of the structure generally.
The design drawings being referenced. Are they public documents, or I suppose I'm asking, how did those engineers get a hold of it? Can I, a public person get it?
This isn't something I've thought about until now, are all buildings' drawings available at some... Central authority, an archive?
This isn't something I've thought about until now, are all buildings' drawings available at some... Central authority, an archive?
The answer is "it depends" on the particular city, county, and/or state.
Florida is a little unusual in that state law makes a very wide range of information public and easy to get. In this case, the town has actually posted all the relevant documents on their website (https://www.townofsurfsidefl.gov/departments-services/town-c...), so you can just click that link to get the plans.
Other places have varying levels of access to building documents. In SF, for example, DBI maintains plans and other documents, but state law prohibits reproduction without the property owner's consent. A member of the public can, however, make an appointment to view the plans in the DBI office. (https://sfdbi.org/DOP)
But generally, yes, all buildings' plans are maintained by (usually) the county-level office that issues permits.
Florida is a little unusual in that state law makes a very wide range of information public and easy to get. In this case, the town has actually posted all the relevant documents on their website (https://www.townofsurfsidefl.gov/departments-services/town-c...), so you can just click that link to get the plans.
Other places have varying levels of access to building documents. In SF, for example, DBI maintains plans and other documents, but state law prohibits reproduction without the property owner's consent. A member of the public can, however, make an appointment to view the plans in the DBI office. (https://sfdbi.org/DOP)
But generally, yes, all buildings' plans are maintained by (usually) the county-level office that issues permits.
Thanks so much. That was useful to learn.
In theory, it seems you can. https://www.buildingrecords.us/blog/how-to-find-blueprints-o...:
“Once the blueprints have been filed by the contractor with the municipality building department, these building plans are public records and technically attainable by anyone wanting to view them.”
That page links to https://www.buildingrecords.us/construction-data/building-pl...
“Once the blueprints have been filed by the contractor with the municipality building department, these building plans are public records and technically attainable by anyone wanting to view them.”
That page links to https://www.buildingrecords.us/construction-data/building-pl...
In Florida, with very limited exceptions, documents related to building permits are public records. Florida has a very aggressive “sunshine law.” Almost all public records fall under it and nearly any time two or more elected officials meet requires public notice and public access (again with limited exceptions).
In the USA most approved plans are public documents, and approval requires code compliance.
Some buildings, like banks or certain public buildings (jails?) don't have publicly available plans.
Some buildings' usage (such as chemical storage or compressed gasses) will require additional detail.
Some buildings, like banks or certain public buildings (jails?) don't have publicly available plans.
Some buildings' usage (such as chemical storage or compressed gasses) will require additional detail.
Typically approved, permitted plans are public record on file at the local authority (city or county usually). If you have an address you can request access to the plans.
I can't find them now because the Google search results for the topic are too noisy but I remember immediately after the condo collapse I downloaded the detailed plans of the building from the city's website. These are not the original drawings, but those submitted for the structural work that was to happen.
https://www.townofsurfsidefl.gov/docs/default-source/default...
https://www.townofsurfsidefl.gov/docs/default-source/default...
At least for NYC, it's not easy to get, but in theory NYC has records of all buildings and renovations (that were legally done) as they have to sign off on the drawings to issue permits.
I wish it was public, but I haven't be able to find drawings but you can find permit info.
I wish it was public, but I haven't be able to find drawings but you can find permit info.
In this case the city proactively made all its files available for the building.
In general, that doesn’t happen (perhaps in Florida it does, I have no experience there). But most cities will only release their record drawings if you have permission of the owner.
In general, that doesn’t happen (perhaps in Florida it does, I have no experience there). But most cities will only release their record drawings if you have permission of the owner.
Rip open any building short of a nuclear reactor complex and you will find such differences. Nothing, ever, gets built exactly as planned. We have only a few photos, blurry ones at that. Hold off on the conclusions until reasonable evidence emerges.
Sure, changes often are required when plans come to a practical implementation, but they (should?) have to be documented and re-verified by the engineers/architects at least for structural components, and the plans should get updated to match the on-site modifications.
Are you suggesting it’s ok for the contractor to not follow the plans?
Of course it’s not ideal, but in the real world the designs are often impossible or impractical to build. If work halted every time construction workers came across a design that didn’t work, instead of tweaking the design onsite and keeping going, nothing would get built.
Source: multi-generational heavy construction family business.
Source: multi-generational heavy construction family business.
So in the case of a tructural support columns or foundations, How does the contractor insure they are still safe and capable of performing?
If you are interested in the Surfside collapse investigation here is the best channel I've found by a guy who does this for a living:
https://www.youtube.com/channel/UC9xpl8LyFRsKXASGHBBj_xQ
The most important section though is buried in a late paragraph:
>Engineers said it seemed unlikely that having less rebar would trigger a collapse in and of itself, even factoring in significant deterioration over many years. An inherent safety factor built into most projects would mean that a slight reduction in steel content would not necessarily lead to disaster.
This certainly suggests that there may have been some shortcuts taken during building, but this is not a smoking gun, and doesn't even start to answer the questions of "why now, after 40 years?"
>Engineers said it seemed unlikely that having less rebar would trigger a collapse in and of itself, even factoring in significant deterioration over many years. An inherent safety factor built into most projects would mean that a slight reduction in steel content would not necessarily lead to disaster.
This certainly suggests that there may have been some shortcuts taken during building, but this is not a smoking gun, and doesn't even start to answer the questions of "why now, after 40 years?"
Like aircraft disasters, most civil/structural engineering disasters have more than one "cause". There is not always a satisfying answer or a single "smoking gun". A bunch of things usually have to go wrong at the same time for a building to collapse catastrophically. Building codes and engineering designs have a lot of assumptions built in, including an assumption that construction does not follow the drawings exactly. But other assumptions include lack of corrosion to a degree, regular maintenance, proper materials specifications, no subsequent modifications, a particular load pattern, etc.
Even then, most buildings are not really designed for much more than 60 or 70 years. Of course, most buildings are also supposed to be designed in such a way that even if it fails, it does not result in a cascading failure. The fact that this particular kind of disaster (apparently spontaneous collapse) is so rare is what makes it newsworthy.
Even then, most buildings are not really designed for much more than 60 or 70 years. Of course, most buildings are also supposed to be designed in such a way that even if it fails, it does not result in a cascading failure. The fact that this particular kind of disaster (apparently spontaneous collapse) is so rare is what makes it newsworthy.
Yeah, I've read _Normal Accidents_, and I follow AdmiralCloudberg's aircraft disasters. There isn't always a satisfying answer, but there often is, or at least one factor that's most damning.
> why now, after 40 years
If this is a case of wear leading to total failure, isn't this like asking why we take the turkey out of the oven on Thanksgiving after 3 hours? Because that’s how long it takes.
If this is a case of wear leading to total failure, isn't this like asking why we take the turkey out of the oven on Thanksgiving after 3 hours? Because that’s how long it takes.
> An inherent safety factor built into most projects would mean that a slight reduction in steel content would not necessarily lead to disaster.
On the other hand, it can lead to disaster, which is why that safety factor exists. We're not doing that just for fun.
On the other hand, it can lead to disaster, which is why that safety factor exists. We're not doing that just for fun.
The space shuttle SRBs were designed with two o-rings, a primary and a secondary. When the primary kept showing signs of burn through, instead of treating that as a problem, it was said that because the secondary o-ring was not burned through, the safety factor was sufficient. But the primary was not designed to burn through. The safety factor did not account for burn through in normal operation, but risk assessments obscured that fact.
>"why now, after 40 years?"
Huh? Cyclic fatigue yo. Incredibly simple and well known killer.
Less whatever type of supports than spec'd to distribute the fatigue across, earlier things fall apart or break from it.
Huh? Cyclic fatigue yo. Incredibly simple and well known killer.
Less whatever type of supports than spec'd to distribute the fatigue across, earlier things fall apart or break from it.
I am partial to the climate change theory.
Rising sea level means higher soil expanding/shrinking with the tides, leading to fatigue
Rising sea level means higher soil expanding/shrinking with the tides, leading to fatigue
But we're talking 4 inches over the life of the building. I'm not sure if buildings are positioned that precisely (if I had to guess, I'd guess it's right around there), the tidal range around Miami looks like it's around 16 inches, and hurricanes and tropical storms will do much more than sea level rise.
I could be wrong, it just seems like there are bigger factors at play, and I'd be surprised that it was build so close to safety margins.
I could be wrong, it just seems like there are bigger factors at play, and I'd be surprised that it was build so close to safety margins.
Possible. I wonder if there was some unexpected external force; a car crashed into the critical pillar at moderate-to-high speed (as high as you can get in a parking lot) or something like that.
One of the worst things about these disasters is that we will get months of daily reports of things being "hinted at". All the noise means that when the final cause is found, no one will care anymore or remember or they'll remember wrong and swear it was all to do with sinkholes or whatever. We need some quite and some rapid inspection of other buildings. Not hints and opinions.
I'm mostly ignoring all the theories until something definitive comes out. All this speculation is just so media outlets can sell ads.
I'm just waiting for somebody to blame 5G.
Just count the number of vaccinated! That much 5G injected into people must be the cause!
/s ... just in case
/s ... just in case
> "one of the worst things"
The set of "worst things about these disasters" includes a pile of corpses. Non-engineering members of the general public continuing to be non-engineers is not even remotely as bad as a pile of corpses. It isn't in this set.
The set of "worst things about these disasters" includes a pile of corpses. Non-engineering members of the general public continuing to be non-engineers is not even remotely as bad as a pile of corpses. It isn't in this set.
[deleted]
The building collapsed because there was less steel due to corrosion than in the design drawings…less concrete too due to spalling.
But mainly it collapsed because the-building-is-falling-apart issues were not addressed despite being obvious even to lay people.
More steel might have delayed the collapse. It would not have avoided it altogether.
But mainly it collapsed because the-building-is-falling-apart issues were not addressed despite being obvious even to lay people.
More steel might have delayed the collapse. It would not have avoided it altogether.
Do you have a source for these claims? Concrete has great compressive strength, and that strength increases as it ages:
> https://www.hunker.com/12003167/tension-vs-compression-of-co...
I haven't seen any claims by qualified engineers that the spalling and corrosion described in the documents or personal reports were to a level that would risk building collapse. I've seen suggestions that the pool and parking deck might collapse, but not ones that would threaten the 40-year old columns holding up the building.
> https://www.hunker.com/12003167/tension-vs-compression-of-co...
I haven't seen any claims by qualified engineers that the spalling and corrosion described in the documents or personal reports were to a level that would risk building collapse. I've seen suggestions that the pool and parking deck might collapse, but not ones that would threaten the 40-year old columns holding up the building.
Was in AEC in Florida for nearly twenty years. Started in a precast plant. During my MArch studied under one of the top forensic architects in Florida, Chuck Goldsmith, after grad school I worked as a Licensed Plans Examiner, got my Florida Architect License in 2007 - though it is currently inactive since I don’t practice there.
So yeah I do know someone with an informed opinion.
Concrete beams fail in tension. Likewise so do concrete moment connections where said beams join columns.
On the other hand columns fail by buckling when they become too slender…which is effectively what happens when a column loses steel and concrete due to corrosion and spalling.
From a personal standpoint I take the shit seriously because people might die if I get it wrong. I have been personally liable for buildings subject to salty conditions and dealt with the kind of people who would rather spend money on crown moldings than stainless steel structural components.
There is a lot of incentive to find rationales for saying the collapse is a one off.
The only unusual aspect is that it is the first. But Florida has buildings with similar issues down one side, up the other, and around the Big Bend all the way to Alabama.
I wasn’t surprised when I saw the building fell. I wasn’t surprised when I read that the first reports went back to the 1990’s. Wasn’t surprised to see the pictures from under the pool.
That’s what happens to concrete in salt air and how people ignore bad news about buildings falling apart.
The real price of fixing the problems with that building would have been comparable to building it new…hundreds of dollars per square foot not the few thousand per unit that the board was willing to spend.
No board is.
So yeah I do know someone with an informed opinion.
Concrete beams fail in tension. Likewise so do concrete moment connections where said beams join columns.
On the other hand columns fail by buckling when they become too slender…which is effectively what happens when a column loses steel and concrete due to corrosion and spalling.
From a personal standpoint I take the shit seriously because people might die if I get it wrong. I have been personally liable for buildings subject to salty conditions and dealt with the kind of people who would rather spend money on crown moldings than stainless steel structural components.
There is a lot of incentive to find rationales for saying the collapse is a one off.
The only unusual aspect is that it is the first. But Florida has buildings with similar issues down one side, up the other, and around the Big Bend all the way to Alabama.
I wasn’t surprised when I saw the building fell. I wasn’t surprised when I read that the first reports went back to the 1990’s. Wasn’t surprised to see the pictures from under the pool.
That’s what happens to concrete in salt air and how people ignore bad news about buildings falling apart.
The real price of fixing the problems with that building would have been comparable to building it new…hundreds of dollars per square foot not the few thousand per unit that the board was willing to spend.
No board is.
> On the other hand columns fail by buckling when they become too slender…which is effectively what happens when a column loses steel and concrete due to corrosion and spalling.
Okay, great. So you're clearly more qualified than I. The above fits with my understanding too. I haven't seen reports that the columns in question were losing dangerous amounts of steel or concrete. Here is the picture from the 2018 report. Is this collapse-level amounts of spalling?
https://static01.nyt.com/images/2021/06/27/world/27miami-mys...
These are 2018 pictures, it could have certainly gotten worse. Enough to threaten the building in 3 years?
There were contractors and engineers bidding on the work for the upcoming 40-year maintenance. Would damage sufficient to threaten the building be obvious at a glance, or would that need testing and detailed analysis?
> The only unusual aspect is that it is the first. But Florida has buildings with similar issues down one side, up the other, and around the Big Bend all the way to Alabama.
This doesn't surprise me, unfortunately.
Okay, great. So you're clearly more qualified than I. The above fits with my understanding too. I haven't seen reports that the columns in question were losing dangerous amounts of steel or concrete. Here is the picture from the 2018 report. Is this collapse-level amounts of spalling?
https://static01.nyt.com/images/2021/06/27/world/27miami-mys...
These are 2018 pictures, it could have certainly gotten worse. Enough to threaten the building in 3 years?
There were contractors and engineers bidding on the work for the upcoming 40-year maintenance. Would damage sufficient to threaten the building be obvious at a glance, or would that need testing and detailed analysis?
> The only unusual aspect is that it is the first. But Florida has buildings with similar issues down one side, up the other, and around the Big Bend all the way to Alabama.
This doesn't surprise me, unfortunately.
See all that fairly fresh paint?
In the first picture they painted over failed concrete. The pictures are said to be “typical.”
The reasons it wasn’t evacuated at the time were business and politics not comprehensive structural investigation.
You see if the client isn’t paying to find problems below the surface, then they won’t be found. And it is common for clients to not want to find such problems. And for engineers to limit their analysis accordingly.
I know what my professional opinion would have been based on those pictures. It would not have been good for my business given the client profile.
Or to put it another way, those pictures show that what happened had a real chance of happening. That’s not hindsight. It would have caused me grave concerns.
In the first picture they painted over failed concrete. The pictures are said to be “typical.”
The reasons it wasn’t evacuated at the time were business and politics not comprehensive structural investigation.
You see if the client isn’t paying to find problems below the surface, then they won’t be found. And it is common for clients to not want to find such problems. And for engineers to limit their analysis accordingly.
I know what my professional opinion would have been based on those pictures. It would not have been good for my business given the client profile.
Or to put it another way, those pictures show that what happened had a real chance of happening. That’s not hindsight. It would have caused me grave concerns.
Yeah that's some pretty widespread spalling on the garage deck. Regardless of what went wrong, I'd be surprised if rust jacking or just plain section loss of the rebar wasn't a principle factor behind the collapse. All of that rebar has just been rusting for an additional 3 years since those photos were taken and it looks like the corrosion was already pretty spread out at the time and no one did anything to address it.
Tyler Ley has dozens of videos on the topic, I know I've seen a great overview of concrete deterioration but he's got so many videos I can't find it. Here's a intro to concrete corrosion though that explains some of it.
https://www.youtube.com/watch?v=mOCJFCaXN0s
Tyler Ley has dozens of videos on the topic, I know I've seen a great overview of concrete deterioration but he's got so many videos I can't find it. Here's a intro to concrete corrosion though that explains some of it.
https://www.youtube.com/watch?v=mOCJFCaXN0s
Could it be they thought they had more time to address the problem because the plans showed a different situation than it actually was?
My educated guess is that there is a cadre of local engineers whose market includes similar buildings and that the deterioration was ordinary enough that the engineers could draw on years of experience to say "it is not likely to collapse because other buildings like it have not collapsed."
As I have said elsewhere, the only thing I suspect is unique is that this was the first building to spectacularly fail.
It failed with people in it because there are tremendous disincentives toward saying the sky is falling even when the sky is falling. It's bad for business and it's bad politics.
Or to put it another way, suppose it was bad design or bad soil. Do you think that the same engineers, owners, contractors, and government agents did everything right on every other building? Think of how hard it is to keep salt off of rebar during construction next to the ocean. Now do so when there is every incentive to save money and no incentive to predict catastrophe.
As I have said elsewhere, the only thing I suspect is unique is that this was the first building to spectacularly fail.
It failed with people in it because there are tremendous disincentives toward saying the sky is falling even when the sky is falling. It's bad for business and it's bad politics.
Or to put it another way, suppose it was bad design or bad soil. Do you think that the same engineers, owners, contractors, and government agents did everything right on every other building? Think of how hard it is to keep salt off of rebar during construction next to the ocean. Now do so when there is every incentive to save money and no incentive to predict catastrophe.
Looking at the photo of the column, I see 3 of the 4 rods in one direction (the side labeled 72) 2 sticking out of the column, can't see the 3rd one presumably sheared off, and the 4th obviously slid down the column, and is the loop sticking up, and 4 of 4 in the other, labeled 73.
Would it help to have a higher rust/concrete ratio?
As I predicted, shoddy concrete work will be the root cause of this.
https://news.ycombinator.com/item?id=27636224
https://news.ycombinator.com/item?id=27636224
I guess that would be a false economy then.
This is a single observation of a discrepancy from a small area in a multi-month long investigation. It's hardly worth commenting on, never mind speculating and extrapolating from.
> less steel reinforcement in certain areas than would have been expected from the 1979 design drawings
They address this later, so it's a clickbait implication.
Who cares if it's different to the design, is it not enough? How does it compare to normal.
Given it's a cookie cutter design the workers would notice if it wasn't enough. 20 years of pumping concrete is enough to know if it's significantly wrong.
If the implication is, this might mean other things are wrong. It goes to how normal is this in industry?
When you look at China and their bad concrete, it goes to pushing things to the extreme, like how will they go in an earthquake.
> Engineers said it seemed unlikely that having less rebar would trigger a collapse in and of itself
They address this later, so it's a clickbait implication.
Who cares if it's different to the design, is it not enough? How does it compare to normal.
Given it's a cookie cutter design the workers would notice if it wasn't enough. 20 years of pumping concrete is enough to know if it's significantly wrong.
If the implication is, this might mean other things are wrong. It goes to how normal is this in industry?
When you look at China and their bad concrete, it goes to pushing things to the extreme, like how will they go in an earthquake.
> Engineers said it seemed unlikely that having less rebar would trigger a collapse in and of itself
> 20 years of pumping concrete is enough to know if it's significantly wrong.
No, that doesn't make sense to me. Concrete buildings are expected to last longer than 20 years, though not expected to last forever. If the shortcuts they take were cutting the expected lifetime of the structure in half, 20 years of experience would not be enough time to see those failures start to happen.
No, that doesn't make sense to me. Concrete buildings are expected to last longer than 20 years, though not expected to last forever. If the shortcuts they take were cutting the expected lifetime of the structure in half, 20 years of experience would not be enough time to see those failures start to happen.
Sorry, I mean a high school educated concrete pumper with 20 years experience will rote learn what the standards are. So the workers should see it's less than standard.
For something to be really off standard, it has to be complex or using illegal immigrant workers or something that is hard to see, like a bad concrete mix being brought in.
It also needs a reason. The cost benefit has to be more than risk. The builders won't risk a $xx million building by saving on re-bar. A contractor might, but they'd have to get away with it.
For something to be really off standard, it has to be complex or using illegal immigrant workers or something that is hard to see, like a bad concrete mix being brought in.
It also needs a reason. The cost benefit has to be more than risk. The builders won't risk a $xx million building by saving on re-bar. A contractor might, but they'd have to get away with it.
It was 1979. The height of Mafia control over large building projects especially anything using cement. I would be totally unsurprised if corners were cut to reduce costs and pad the pockets of some capo who was running the union on that job.
Personally, I have a feeling it might have been rusted rebar in the basement that caused the accident?
Rebar can completely rust through, even encased in concrete if continually exposed to water. This happens only a very small percentage of the time though. It takes more years than this building was up though?
I know of ferro cement boats that have hollow spaces where the rebar used to be because the owner didn't know about electrolytic, and galvanic action.
(I would love to hear from an engineer, or a trades person on this. Have you ever seen rusted rebar in such a young building?)
I would not have ever thought rebar could rust that quick over pool water, or rain water though in those columns. I originally though the standing water in the basement was salt water, which might make the rusting process easier.
I am no expert. I'm not an engineer. I just know rebar can rust through in concrete. It is very rare though. I have seen one column where rust got to the rebar, and the rust went through the concrete. It was like a rust highway, and the rebar was the road. Rusted right into all the rebar encased in the concrete.
I do want to stress I have never seen a collapse like this, even when building codes were not as strict as they are now. Building codes have been very strict for probally 70 years.
I hope they don't revise building codes again unless they find the exact reason this building failed. The building codes in high rises/apartments/homes you guys live in are in many cases overkill.