If it’s anything like a regular house sump pump (which i suspect it’s not, they should be way higher duty in a building like this), I’ve seen the pumps last 10-20 years without too many issues.
But that would point to this being a case of brutal conditions with constant use. My real question was to try and grasp how much water they were pumping compared to others.
Yes, which is exactly the problem here. Those pumps should not have been in constant use. The fact that they failed so often means they were being run far more than would be expected under normal conditions.
Yeah, i imagine in cases where this is to be expected, the sumps themselves need to be much larger (or have more of them) and the pumps need to be higher duty and intended to move more water. Certainly exceptional, but i'd hope anticipated in the design.
Our sump here runs all the time when it rains, but then it goes for weeks without moving any water (especially in the winter). When we moved into this house, the pump was broken, but there was also water damage in the basement. First thing i did was replace it and now its a common sound to hear the pump running.
I lived in a place in Ontario where the grading wasn't correct and my sump pumps were failing every 18-24 months. It would run for days after a heavy rain.
Miami is making the same mistake New Orleans made 100 years ago. They're trying to artificially lower their water table to improve drainage, but it creates a cycle of subsidence, which makes flooding worse, which makes them pump more, repeat.
They luckily don't have large organic deposits (that I'm aware of), so total subsidence will be much less than New Orleans, but same concept.
Back to your question, the pumps were probably designed or spec'd for a capacity that they are having to exceed in increasing amounts.
That also sounds like it would pull in salt water, which as I understand it is a problem at least in Jakarta: a lot of previously fresh-water wells in the area have become salty due to ocean water seeping in to fill the void.
That's for deep water drinking wells. Baton Rouge and south Louisiana are going through that now, with salt water penetrating a fault line that was once considered a barrier. The industrial corridor along the Mississippi consume an unbelievable amount of fresh water, so the same lesson might not apply to most areas.
Pumping drainage and the ground water table is probably drawing salt water, but at shallow depths.
Not deep enough for actual water wells.
Obviously it depends a lot on the specific type of pump, motors are - generally speaking - very long lasting, I would say (proper type of pump, properly dimensioned, used according to specs, and maintained/repaired) anything between 10 and 20 years.
The more common issues are outbound leaks (from the axle gasket) in external pumps and inbound leaks (from the outer case or gaskets) in submersible pumps, and of course from time to time you need to change the bearings.
In the case of submersible pumps, leaks usually mean also a motor failure (again it depends on the type of pumps) expecially on rarely used pumps as bearings will clog and the motor will then likely need too power, and overheat.
On the other hand, external pumps (air cooled) often overheat because of the poorer cooling, if subjected to lots of "start and stop", electrical motors, particularly if large, tend to create a huge drain of power (often 3x to 5x) when starting (as compared to normally running) and this inrush of current translates in a huge amount of heat (and more generally stress to the motor), so many starts in a limited time are not good for the life of the motor, lately things were mitigated by electronic starters that allow for smoother (less peak Amps) starting.
The electrical setup/controls may also play a role, a good, well calculated pumping station (such as those used to evacuate leaks in an underground construction) is generally 100% redundant (i.e. two pumps when only one is needed, in some cases 300%), and have automations that alternate the use of pumps (so that each motor and bearings actually run when pumping is required) and use "the other pump" if there are too many motor starts in a given hour, plus there can be a sort of valve that allows to pump the water within the reservoir, so that even if there is no need to pump water "out" pumps are "exercized" periodically, this latter is also often used to avoid too many starts, once a pump is started, it runs for a given number of minutes minimum, part of which is actually used to pump water outside - i.e. responding to the event that triggered the start - and the rest it runs "idle" pumping water within the reservoir through the by-pass valve, so that if a new event re-triggers the start, the pump is already running and only the valve is closed to make it pump water out.
But otherwise what you routinely (I would say every two-three years for external pumps and maybe 5 years for submersible ones) do is check gaskets and bearings and replace them if needed.
This is media doing the media thing. In fact even small cracks are perfectly fine - it at least that’s what our civil engineering professor told us. In hindsight everyone of these minor ones will be put under a microscope.
That said, if the building had a pattern of these it’s probably not very well maintained.
Cracks are actually required for reinforced concrete to work properly. The concretes got to give so the steal can take the tension, and you want big cracks to show up during before and during failure, specifically because it's a warning sign.
You're absolutely correct. RC design is very complex, but very conservative.
There should have been 'oh shit' levels of cracking and rebar exposed, and in specific places. That's not what the infamous "inspection" showed.
And even then, it should have tolerated multiple complete local failures before cascading catastrophic failure.
ETA: It's hard to see in these photos bc of the the quality, but the rebar in the pool pump room is more concerning than anything in the 2018 report, but still doesn't look anywhere close to failure.
(Actual structural inspections should be able to clearly show cracks 1/16th" or smaller, at a resolution you can measure them from the picture)
Edit 2:
The equipment room in that picture didn't even collapse.
A- major proportion of civil/structy engineers are going into retirement, their numbers not supplanted by new blood. It's just not a calling anymore.
B- USACE redacts their dam and bridge inspection databases by zeroing out inspection dates. They're obviously managing the external perception of this process, and internally prioritizing best they can.
C- they only have ~32k employees, of which there are only so many pertinent engineers, handling 200k bridges and 90k dams. Overwhelmed is an understatement. Then there's the budget situation.
Sure. Guess my actual point was the lead time- it takes years to attract potential students, train them into engineers, give them some experience under the belt. Years to build up an effective workforce to fill this gap. Decade? Perhaps decades to fill this somewhat specialized labor deficit?
Yikes--it looks even worse on Google Street View.[0] That appears to be bridge P-03-023.[1] According to MassDOT, it was built in 1959 and "reconstructed" in 2010--which apparently meant "replacing the bridge decks, ... and upgrading bridge and approach railings,"[2] not fixes to the part that appears to be disintegrating. It was last inspected in 2019.[1]
I agree with your larger point. We are only seeing the data point of a building that everyone said had a lot of work and then collapsed. But, for all we know, 10% of all large buildings would have some element that one subset of contractors would flag as being very dangerous.
Still, I think it is an illuminating case study. Given how big the death toll is, I'm very open to the idea that building inspections need more transparency or more technology.
The photos could indicate a general lack of proper maintenance and concern, but these photos aren’t even from the part of the building that collapsed:
> The equipment room runs along the southern wall of the building — an area that did not collapse.
The internet commentary isn’t very helpful. We need to wait for official reports, but the media will try to extrapolate from any tiny pieces of information in the mean time
Yeah, I noticed a lot of attention in the media is on the pool support corrosion, but it apparently did not collapse, though it seems to have emptied out. With the other anecdotal notes about the subfloor pumps wearing out and water pooling in the subfloor garage closer to the building, it seems more likely there was a longstanding leak that lead to a sinkhole forming or perhaps rebar corrosion. I recall from my civil engineering course that concrete has a high compression yield point but a poor tensile one, hence the need for rebar. Take away part of the foundation or wear away the structure in such a way that the weakened rebar is forced to take the load, and suddenly you have a catastrophic failure like the one that occurred.
If another part of the building was in such bad condition, there is a high probability that the part of the building that collapsed was also in bad condition.
The contractor was a pool contractor. He saw from experience that it looked bad, but was not in any position to pronounce on the structural integrity.
Semi related, I live in a very badly maintained major city, where driving under many bridges we can see cracking, big chunks of concrete that fell away, exposed re bar, etc. To me it looks very scary, but I have no real reference point. If a bridge collapses, the news will be able to interview someone who says what I said above about the appearance, but the only thing that really matters is an engineer's report.
I hate to say this, but almost anywhere in North America has the right weather conditions, and lack of local/state/federal funding models to cause this problem. I don't know enough about the south to comment, but I could believe MX and below have the same problem due to lack of capital works programs
I believe in the US governance space there was a proposal for a 10-40y roads and bridges reconstruction effort. I have no idea if it survived factional politics.
Well the contracter isn't a structural engineer so he can't make the determination that "this building will collapse in two days".
The media has definitely been exaggerating the evidence that management had, but it's still clear that they needed to be more aggressive in inspection and restoration.
I doubt either the HOA or the condo owners would have been amicable to a costly special a$$essment for restoration. Everyone is a good quarterback after the fact.
Indeed. The condo members could have easily been the ones fighting action.
My grandparents used to own a condo where the people there were unwilling to spend money on anything. What would have been a couple hundred dollar special assessment morphed into a several thousand one very quickly multiple times, as nobody was willing to spend the money fixing things.
> The president of the Champlain South Towers condo association told residents in April their building was in desperate disrepair and urged them to pay the $15 million in assessments needed to fix structural problems, in a letter reviewed by The Wall Street Journal.
> ...
> The purpose of the letter, dated April 9, 2021, was to explain to residents the worthiness of the construction projects for the 40-year-old building ahead of the following week’s meeting about a proposed special assessment of $15 million to be paid by residents.
Even if they had given the money, there’s no way the work would have been completed (or started, most likely) before the collapse. If anyone knew that the building was in danger of structural failure it should have been condemned, not renovated with residents in place.
In the "everything's rosy" universe where things go the right way, they would have had an engineer come out and start looking and then say "everyone get out."
Unfortunately, this isn't the "everything's rosy" universe.
---
That money... its about $120k/unit in the condo.
You can get a condo on Miami Beach for $225k. Some digging on Zillow suggests that a condo built within the last 20 years will get you into the $450k range without difficulty and very easy to go beyond that.
> The tower’s rooftop apartments would have added significant weight but they were accounted for in the revised design, said Roberto Leon, a professor of construction engineering at Virginia Polytechnic Institute and State University, who reviewed the building plans.
> The structural plans show that the size of the columns and reinforcements would have been typical for that time, and the roof would have had limited ability to redistribute the building’s load if one of the columns were to fail, he said.
> That could mean a failure in one column could bring down an entire structure, which could have been what occurred with this building, Mr. Leon said.
My understanding was that there's literal years of earlier documented to-be-fixed (fairly urgently) issues that this contractor wasn't looking at this go around.
Morabito Consulting did a survey almost 3 years before, listing repairs that needed to be done. I think images like this is just evidence that lawyers will accumulate. The media will just use these images to add drama.
In West Seattle, they shut down the bridge from cracks, but it did take them a while.
>>Those taut tendons serve to push the concrete together like giant rubber bands. They help the concrete resist the gravity and other forces that could crack or otherwise pull it apart.
>>“In most cases [of] cracked concrete, you're not too bothered about the concrete not operating properly,” Stanton said. “You are worried about the steel inside becoming corroded.”
oh wow, i'm from Seattle (abroad since 2013) and didn't know that bridge closed! Such a major artery to West Seattle being shut down. Getting in and out of Alki must be annoying af.
Obviously great that they caught it and have a rapid response, but pretty crazy.
They're referring to the West Seattle Bridge, which was recently closed due to structural issues. It seems you're referring to the Alaskan Way Viaduct, which was also not structurally sound, but was replaced with a tunnel.
> I keep hearing about lawyers, but who exactly gets sued?
Whoever arguably had an unfulfilled duty. I’d say the condo association and its individual officers (who would have received the damage reports and arguably failed in their duty of care to owners and indirectly renters with regard to them) would be a good candidate. For renters or their families, their individual landlords would also be potential targets.
The condo association officers are likely volunteers, elected by the condo owners, and indemnified by the association. They are just homeowners like everyone else, unlikely to have any expertise in engineering or understanding engineering reports. And possibly also now dead.
> The condo association officers are likely volunteers, elected by the condo owners, and indemnified by the association.
Indemnity tends to have limited scope, and whether a particular claim is within it is a question resolved in a lawsuit.
> They are just homeowners like everyone else
No, they aren't, because they are differently situated.
> unlikely to have any expertise in engineering or understanding engineering reports.
Special expertise is not required for culpabale negligence or culpable non-, mis-, or malfeasance. Whether, for instance, the reports they received provided sufficient notice of danger that they should, under the duty of carr applicable, have acted differently and their failure to so contributed to the harms to persons and property in the collapse is...precisely the kind of question resolved in a lawsuit.
> And possibly also now dead.
Death does not erase legal liabilities, generally. Its true that, after published notice of death, there is usually a limited time to file claims against the estate (which, with a live defendant, might have more time under applicable statutes of limitations, etc.) But that just adds urgency to identifying and acting on potential claims here, where, yes, some of the potential defendants might also have died in the event.
Depending on their insurance they may be able to sue themselves and have the insurance cover it. Sole trader workers compensation can work like this too.
What if they acknowledged the problem, and acted on the information available by commissioning the repair/redesign work that's necessary but the work didn't happen fast enough to avoid the failure? It seems feasible that some structural weaknesses might not be easily measured/assessed in situ.
The media has treated the report from from the consulting engineers as a semi-smoking gun, I read it - I have a background in civil construction and work in another engineering adjacent field, and if the issues they identified ends up being the root cause of this event, then I think that this will be a case study in how engineers need to learn to communicate both urgency and seriousness to non-engineers.
If this guy honestly felt that the building was at risk of imminent failure - which is what the media generally has been implying, it was not sufficiently communicated in the language used in the report, which fails to convey any sense of urgency. There is a whole bunch of pro-forma jargon, and pro-speak however, which seems to mask whatever its trying to say, and drains away the urgency from this.
Consider the de Soto bridge in Memphis, TN, the one that carries the I-40 over the Mississippi. A crack in a main truss was found earlier the year during a scheduled inspection, and the bridge was closed immediately. Some guy on a holiday took photos in 2016, and the crack was visible then: https://www.wmcactionnews5.com/2021/05/18/photos-show-i-brid...
So - yes, things hold up until they suddenly fall over.
You wonder if there were political reasons behind the language used - the building should have been condemned since it was at immediate risk of collapse, but rich people do not like to be inconvenienced. So the engineer decided to protect himself, he told and hid the truth at the same time.
>Morabito Consulting did a survey almost 3 years before, listing repairs that needed to be done.
It had more money budgeted for landscaping than actual replacement of anything structural (which was just 2500sqft of garage decking). Even that would probably better be described as waterproofing.
There was a lot of waterproofing, electrical, and HVAC work, as should be expected on a building that old.
But there was nothing in that proposal that would have done anything at all to prevent this.
The best case would have maybe been to uncover the real problems earlier, but most of the structural and waterproofing work was near the pool, which we know survived. So probably not.
I mean, the US has a huge culture of waiting for shit to happen before doing something about it. People don't take warning signs seriously.
It happens in buildings, it happens with electrical fire safety, it happens in healthcare (insurance and doctors largely don't believe in prevention in my experience).
Yes, but the US also generally takes pretty swift action to make regulatory changes when disasters happen. Florida (and Miami-Dade County in particular) is known for their strict building code now, and I'm sure we'll see some additional changes as a result of this.
I suppose, but people had to die for those changes to happen. They should have taken pictures of warning signs seriously. They should have had emergency forces onsite within hours of those pics getting to the bottom of what's going on, and evacuating the building.
The contractor was there to assess a cost for cosmetic improvements to the pool. If the building owners knew of the structure problems years in advance why was there a cosmetic improvement to the pool happening anyway?
Should have spent the money on actual improvements not cosmetic pool updates.
This is a common behavior. Maintenance is frequently deferred until something catastrophic (but hopefully not too catastrophic) forces it and then usually the cost is much higher than on-going maintenance would have been. Cosmetic improvements, on the other hand, get enough visibility to be addressed more readily.
Changing a building's facade, cleaning up the entry area and gardens, but totally neglecting cooling systems and water systems (as examples of systems needing maintenance but with usually less-than-fatal consequences when neglected). It's very frustrating, and common to most (if not all) industries.
The cosmetic improvements were going to be done as part of the same project to correct the structural issues.
> The contractor visited the condo building last week to put together a bid for a cosmetic restoration of the pool as well as to price out new pool equipment — a small piece of the multimillion-dollar restoration project that just was getting underway at the 40-year-old building.
When lots of people have to agree on something, it's easier to batch everything up into one vote. It's the same reason we get giant spending bills in Congress instead of more focused ones.
I think part of it is a need to feel like this isn’t something that can just happen. It helps to feel like “the system” or “someone” should have known but dropped the ball. That way we can tell ourselves if our building were in the same situation, we’d know. This wouldn’t (and couldn’t) happen to me is a comforting lie we like to tell ourselves whenever theres a tragedy.
I think maybe humans as a species aren’t so great at processing freak accidents. For some reason it’s easier to accept when we have someone to blame - real or imagined.
Well, you/one personally really can't worry about the structural safety of all buildings and infrastructure you're exposed to. You simply don't have knowledge, permission or time. That's why we need the system to take care of this and prevent such accidents from happening, as well as imposing general emergency safety in case of fire etc.. Otherwise, our current life would simply be impossible.
I live in a small building with just 3 units (again, only THREE owners). An issue w/ the building came up in January, it's been six months and we still haven't agreed on who are we going to hire, who is going to pay for what, etc...
I can only think it is essentially impossible to get 20+ tenants to agree on something that involves them spending money, time, inconvenience, ...
> We have covered so much ground already to get the project rolling, it’s not surprising everyone is still asking about those items. Everything reviewed in this letter has been publicly presented, discussed, and voted on as necessary. We have discussed, debated, and argued for years now, and will continue to do so for years to come as different items come into play.
Sounds like you're not far off with your assumption. From the author's tone, it feels like he's annoyed.
I worked in concrete repair for half a year, I mostly only used the jack hammer and angle grinder but I paid some attention.
Here is what I think I know:
When rebar corrodes it expands and that means even more air, water and salt can reach even further into the construction, meaning even more rebar is exposed and starts corroding. Edit: this probably weakens the concrete as well both because of exposure to the atmosphere and because of the cracking action but this last one is just an educated guess from my side.
How we worked was our foreman went first with an ultrasound device to detect the rebar and how much cover it had. He'd then sample the concrete by cutting into it, knocking out one side of the cut using a hammer and spray indicator fluid (I guess fenolftalein) on it. If the concrete turned pink it was healthy. You could measure how far out it was healthy.
If the measurements rebar was out in the damaged concrete we would expose it and apply protection before closing the wound. Sometimes we would also use a sledgehammer to adjust the rebar somewhat.
A number of factors influence how long concrete lasts before it needs maintenance:
- How far rebar is buried.
- The quality of the concrete as it leaves the mixer
- If the driver had lunch break or got stuck in traffic after loading the truck and added water to prevent anyone from noticing. Concrete starts curing immediately after mixing so you have limited time before it needs to be in the mould
- How well the concrete was vibrated to make sure it filled all gaps and that no significant air pockets was left
- How close you are to the sea
There's always someone on HN who knows something about everything and hopefully this was one of my turns to satisfy some of the curiosity for someone :-D
Edit: working with those older guys was really interesting. Seing a 70-year old bloke throw around tower lift parts that I figured I didn't have a chance of lifting. All the stories. The time I played with a bunch of cards and one of them askes to borrow it and started showing off crazy tricks; turned out he had a bronze medal from Nordic magic for juniors (and since he was now close to retirement and his hands were large and swollen I also got a chance to see what was really happening :-)
It was also the first place I know that actually practiced HSE. Others laughed but this team had 1-2% extra profit margin and I remember we got a nice bonus too. Ended up at around $15/hr which was close to twice what I used to get for much harder and dirtier work.
This was the spring of 2001. They liked me so when I left for school I got a nice job cleaning the work sites.
They didn't see a collapsing building 2 days ago. The article mentions water damage as early as 1990. Blaming the problem on the last person that touched the building is absurd.
I spoke with an engineer working on a job site near Seattle for a tech company, their soil stability test holes kept failing inspection but they were allowed to keep retrying in other areas. It took 15 tries to get a sample that would pass, and the state inspector was ok with it. They didn’t want to cause issues for such s big company in such a large project. I was cautioned to not go near that building ever.
I’ve always wondered how many other buildings are in the same state.
I know absolutely nothing about whistleblowing laws, but, like, shouldn’t this be driven by policy? I get that lawmakers might not have whistleblowers’ best interests in mind but this feels squarely on Congress to me. Might be an interesting space tho. What do I know.
The insurance and mortgage companies should have been interested in the information but I doubt whoever had the information would have thought to contact them and, even if they did, I doubt the companies would have had a reliable process for receiving and investigating that sort of “whistleblower” claim. It’s even more complicated when it’s a condo building and there are any number of different banks and insurers involved, rather than just one. Everyone assumes someone else is looking at X and so they all ignore it a bit more than they should.
But, if you’re looking for the business niche, I’d guess they’d be your customers. Basically a “bug bounty” program for underwriters of tenancy in common real estate.
Pretty sure there's some law in the US where you get a percentage of the judgement if you whistleblow. Maybe it's specific to the finance industry. Someone help me out.
They’re called qui tam suits[1] and in the US they’re commonly brought under the False Claims Act[2] which can apply to any government contractor but Medicare Fraud is a big piece. The way it works is the “whistleblower” files a civil suit with the allegations and then the government can choose whether or not they want to take over the case. If the government think your allegations are solid and the potential recovery is worth their while they’ll take the case and you’re entitled to 10% of anything they ultimately recover. If, for whatever reason, the government decides not to get involved, you can continue the case on your own (but kind of on behalf of the government... it’s a bit weird how it works) and anything you recover goes to the government but you get 30% for your trouble.
The SEC also has a whistleblower program that another commenter has linked and, as of recently, they have really been paying out a lot of money to whistleblowers. Larger sums and more frequent payouts than we’ve ever seen before.
Yeah, a Code Enforcement department for a large municipality would pay for reporting automation. I don’t think it would prevent this event. It’s a condo, so the building is probably maintained by a POA. Who would have an incentive to inspect the building? Who has a contractual obligation for maintenance? POA members. Who has to pay for repairs? POA members. Who now has an incentive to avoid repairs? POA members. Would you dime yourself out to be on the hook for repairs that may exhaust your discretionary income for many, many years? Or would you “touch up the X-ray” as Warren Buffet put it?
POAs are a terrible idea and I wish they didn’t exist. Distributed ownership always seems to incentivize bad behavior.
their soil stability test holes kept failing inspection
What do you mean by "stability test holes kept failing inspection"? If you're referring to geotechnical boreholes, there's nothing to inspect - it's a test of (among other things) soil strength. It's certainly possible to have soft/loose/low-strength soils (soft/loose solis frequently cause the borehole to collapse on itself, that's not unusual) but that doesn't speak toward safety. The building just has to be designed & constructed to account for that, usually by stiffening the soil and/or using a pile foundation.
I’ve always wondered how many other buildings are in the same state.
Given the loose soils and relatively high-water table in Seattle? Pretty much all of them. Structures can be built on soft ground, it just needs to be done right.
No. The point was that the engineers should have fixed the design, but since the job was already started, it would cost too much to change or delay, so others decided to keep testing to find a result to Cherry pick.
Also, no, not referring to buildings on normal engineering. I’m talking about buildings built with corners being cut. This was also not in Seattle and wasn’t low lying, was on a hill.
A quote I often hear referred to in inspections: "It's not our job to catch you, it's your job to follow the law". If someone wants to deliberately avoid certain inspections, it's not that hard.
But your friend's story doesn't make a lot of sense. The foundation would have been engineered for the soil that was there, not designed, then tested to see if the soil matched. Even cutting corners, it doesn't make sense to do the steps out of order. So I imagine there's more to the story.
of course you need piles deep enough, and boreholes soil test results probably factor into the decision of how deep it should be. The $100M fix for the tilting and sinking 58-story SF tower built in 2009 with "floating" piles not reaching the bedrock :
"The solution, likened to putting a bumper jack next to a flat tire, will involve the installation of 52 piles along the north and west sides of the tower. The piles will be beneath the sidewalk, 250 feet into the bedrock of downtown San Francisco, and be tied with the original 60-90-feet-deep foundation piles."
A floating foundation can be safe. But not if you dig a giant hole next to it and pump out all the water. SF quietly settled and paid for most of the repairs.
Soil stability and it's ability to support a building depends a lot on water situation.
reminded - back at University i worked summers on construction mostly doing foundations in Siberia in permafrost zone. The most memorable part of the quick introduction to the profession there was when they showed us several buildings which didn't have piles deep enough - most of those you could easily spot from a distance by the building shape defects like tilting, bended roofline, etc... because if piles aren't deep enough the foundation pretty much becomes really "floating" during warm season after several cycles of freezing/thawing.
Poor soils can be managed with good foundations. You can put a building on water with the right foundation design. In the case of an office, the safety factors in design are usually pretty high. I’m assuming soil sampling is for modified proctor density. Usually, the criteria for those are fairly arbitrary. Some soils are so sensitive to moisture content that density measurements aren’t very informative. Not blowing up a multi-million dollar construction schedule over a few mm of consolidation is probably a reasonable take.
If he’s doing the CE&I and let it pass, then he has nobody to blame but himself. Knowing it’s wrong and certifying that it’s right entails a lot of professional risk in this industry. I suspect his concerns aren’t too serious or someone else is certifying the work.
One other situation I can imagine is that the risk is outside his domain. Example: I saw a company scrape flat clays out of a roadway and use that material as fill for slab-on-grade foundations of duplexes. I wouldn’t expect those to last long, but the developer is also the owner, so he’s only hurt himself. I don’t find the owner to be particularly sympathetic, I only certified the road construction, and the only person to report the poor practice to is the owner himself, who also hired the crew.
I guarantee you one thing - no matter the ultimate observable precursors, I bet there are thousands of buildings across the states that have the same precursors and nothing will be done.
Fundamentally maintenance is just not prioritized. This is true both in software and in general. If you want to scare yourself just Google elevator death. Elevators are a perfect example of the issue in that there are regular inspections but inspections do not imply maintenance.
I am not even sure how exactly you foster a culture of maintenance at this point.
After reading your comment, I did Google "elevator death", expecting to be dismayed. I came away oddly reassured. It seems that fatal elevator accidents are rare, and that you have much more to fear from your fellow elevator passengers than the apparatus itself, if the news articles are anything to go by.
> In the pool equipment room, located on the south side of the underground garage, the contractor saw another problem — exposed and corroding rebar in the concrete slab overhead.
Imagine if the building was not in a wealthy neighborhood. Most news would focus on the contractor being racist and how dare they take their lives of underprivileged communities.
As long as the building is in a fancy neighborhood, this is not big news.
Generally speaking, I think two things went wrong here.
1. Almost anyone seeing all the warning signs probably didn’t think an entire building could collapse or partially collapse. Things could look terrible, but maybe not enough to say, “I need to get out of here before this building collapses.” Yes, that is said in old building and homes but it just doesn’t compute in building this size. That is why a professional inspector needed to be involved.
2. Time was also a problem here. In the US, a modern city with a 40 year old building just doesn’t compute. It’s actually kind of old in the US, especially with problems like this. Similar to #1, it didn’t compute a building this size could collapse this way. That is why a professional inspector needed to be involved.
how can any engineer or inspector know that what they can see from a surface inspection means a building is about to collapse? How many buildings do they inspect with damage that don't collapse? all of them until this one. So when they see damage they say, this should be repaired, and then when the repair gets underway, maybe people see that it needs more than anticipated, and it all gets fixed. Probably by that point in time the inspector is out of the picture.
>also, when performing any concrete restoration work, it is impossible to know the extent of the damage to the underlying rebar until the concrete is opened up. Oftentimes the damage is more extensive than can be determined by inspection of the surface.
This wasn't something that flew under the radar. They had done a lot of due diligence on it and were about to start an extremely expensive and complicated project to fix it.
I suspect that some of the delay was due to the amount of work it took to get the huge special assessment lined up. It's likely that some of the residents who were killed had been fighting the condo association to avoid paying so much.
Here's a long letter that the condo board recently wrote to the unit owners about the concrete repair work.
>that estimate indicated that the concrete damage observed would begin to multiply exponentially over the years, and indeed the observable damage such as in the garagehas gotten significantly worse since the initial inspection.When you can visually see the concrete spalling (cracking), that means that the rebar holding it together is rusting and deteriorating beneath the surface.Please note that the original scope ofwork inthe 2018 report has expanded. The concrete deterioration is accelerating. The roof situation got much worse, so extensive roof repairs had to be incorporated.
>Because so muchof the needed concrete/waterproofingwork is underground, we must pull up almost the entire ground level of the lot to access the areas that requirerepair. That means we have to put itall backat the end. This includes the pool deck, the entire entrydriveand ground level parking,north side contractor parking,and planters/landscaping. Electrical work and plumbingare involved almost everywhere. Balcony concreterequires repair/waterproofing,and the railingsrequire repair. And-we have to bring all this up to current codewhen repairs are completed.
interesting they only had $168,000 earmarked as structural repairs out of $15,000,000. Clearly they did not know the extent of the damage. Most of the work was in waterproofing and balcony repairs.
129 comments
[ 2.7 ms ] story [ 175 ms ] threadHow long should a pump motor last? Anyone know?
Our sump here runs all the time when it rains, but then it goes for weeks without moving any water (especially in the winter). When we moved into this house, the pump was broken, but there was also water damage in the basement. First thing i did was replace it and now its a common sound to hear the pump running.
quality, conditions, actual duty cycle vs designed, etc.
They luckily don't have large organic deposits (that I'm aware of), so total subsidence will be much less than New Orleans, but same concept.
Back to your question, the pumps were probably designed or spec'd for a capacity that they are having to exceed in increasing amounts.
https://en.wikipedia.org/wiki/Raising_of_Chicago
Pumping drainage and the ground water table is probably drawing salt water, but at shallow depths. Not deep enough for actual water wells.
Obviously it depends a lot on the specific type of pump, motors are - generally speaking - very long lasting, I would say (proper type of pump, properly dimensioned, used according to specs, and maintained/repaired) anything between 10 and 20 years.
The more common issues are outbound leaks (from the axle gasket) in external pumps and inbound leaks (from the outer case or gaskets) in submersible pumps, and of course from time to time you need to change the bearings.
In the case of submersible pumps, leaks usually mean also a motor failure (again it depends on the type of pumps) expecially on rarely used pumps as bearings will clog and the motor will then likely need too power, and overheat.
On the other hand, external pumps (air cooled) often overheat because of the poorer cooling, if subjected to lots of "start and stop", electrical motors, particularly if large, tend to create a huge drain of power (often 3x to 5x) when starting (as compared to normally running) and this inrush of current translates in a huge amount of heat (and more generally stress to the motor), so many starts in a limited time are not good for the life of the motor, lately things were mitigated by electronic starters that allow for smoother (less peak Amps) starting.
The electrical setup/controls may also play a role, a good, well calculated pumping station (such as those used to evacuate leaks in an underground construction) is generally 100% redundant (i.e. two pumps when only one is needed, in some cases 300%), and have automations that alternate the use of pumps (so that each motor and bearings actually run when pumping is required) and use "the other pump" if there are too many motor starts in a given hour, plus there can be a sort of valve that allows to pump the water within the reservoir, so that even if there is no need to pump water "out" pumps are "exercized" periodically, this latter is also often used to avoid too many starts, once a pump is started, it runs for a given number of minutes minimum, part of which is actually used to pump water outside - i.e. responding to the event that triggered the start - and the rest it runs "idle" pumping water within the reservoir through the by-pass valve, so that if a new event re-triggers the start, the pump is already running and only the valve is closed to make it pump water out.
But otherwise what you routinely (I would say every two-three years for external pumps and maybe 5 years for submersible ones) do is check gaskets and bearings and replace them if needed.
The contractor clearly thought it was "a lot of work" but not to the level of "this building needs to be condemned immediately".
So many articles are screaming "look at that paint chipping and concrete exposure, obviously the building was going to go collapse"
I don't think it's so obvious or am I just naive?
That said, if the building had a pattern of these it’s probably not very well maintained.
But it's highly dependant on size and location.
There should have been 'oh shit' levels of cracking and rebar exposed, and in specific places. That's not what the infamous "inspection" showed.
And even then, it should have tolerated multiple complete local failures before cascading catastrophic failure.
ETA: It's hard to see in these photos bc of the the quality, but the rebar in the pool pump room is more concerning than anything in the 2018 report, but still doesn't look anywhere close to failure.
(Actual structural inspections should be able to clearly show cracks 1/16th" or smaller, at a resolution you can measure them from the picture)
Edit 2:
The equipment room in that picture didn't even collapse.
A- major proportion of civil/structy engineers are going into retirement, their numbers not supplanted by new blood. It's just not a calling anymore.
B- USACE redacts their dam and bridge inspection databases by zeroing out inspection dates. They're obviously managing the external perception of this process, and internally prioritizing best they can.
C- they only have ~32k employees, of which there are only so many pertinent engineers, handling 200k bridges and 90k dams. Overwhelmed is an understatement. Then there's the budget situation.
D- then there's the buildings.
High paying jobs are always in fashion and the demand for those jobs should increase because the public doesn't like seeing children dead in rubble.
https://imgur.com/gallery/ZSMg1pZ
They cleaned up the chunks of concrete that had fallen from the beam.
[0]: https://www.google.com/maps/@42.5194293,-70.9935589,3a,75y,3...
[1]: https://www.arcgis.com/home/webmap/viewer.html?url=https%3A%...
[2]: https://hwy.massdot.state.ma.us/ProjectInfo/Main.asp?ACTION=...
Still, I think it is an illuminating case study. Given how big the death toll is, I'm very open to the idea that building inspections need more transparency or more technology.
> The equipment room runs along the southern wall of the building — an area that did not collapse.
The internet commentary isn’t very helpful. We need to wait for official reports, but the media will try to extrapolate from any tiny pieces of information in the mean time
Semi related, I live in a very badly maintained major city, where driving under many bridges we can see cracking, big chunks of concrete that fell away, exposed re bar, etc. To me it looks very scary, but I have no real reference point. If a bridge collapses, the news will be able to interview someone who says what I said above about the appearance, but the only thing that really matters is an engineer's report.
I believe in the US governance space there was a proposal for a 10-40y roads and bridges reconstruction effort. I have no idea if it survived factional politics.
The media has definitely been exaggerating the evidence that management had, but it's still clear that they needed to be more aggressive in inspection and restoration.
My grandparents used to own a condo where the people there were unwilling to spend money on anything. What would have been a couple hundred dollar special assessment morphed into a several thousand one very quickly multiple times, as nobody was willing to spend the money fixing things.
https://www.wsj.com/articles/miami-area-building-collapse-co...
> The president of the Champlain South Towers condo association told residents in April their building was in desperate disrepair and urged them to pay the $15 million in assessments needed to fix structural problems, in a letter reviewed by The Wall Street Journal.
> ...
> The purpose of the letter, dated April 9, 2021, was to explain to residents the worthiness of the construction projects for the 40-year-old building ahead of the following week’s meeting about a proposed special assessment of $15 million to be paid by residents.
Unfortunately, this isn't the "everything's rosy" universe.
---
That money... its about $120k/unit in the condo.
You can get a condo on Miami Beach for $225k. Some digging on Zillow suggests that a condo built within the last 20 years will get you into the $450k range without difficulty and very easy to go beyond that.
There are other things coming to light too... like they added a penthouse ( https://www.wsj.com/articles/miami-area-condo-that-collapsed... )
> The tower’s rooftop apartments would have added significant weight but they were accounted for in the revised design, said Roberto Leon, a professor of construction engineering at Virginia Polytechnic Institute and State University, who reviewed the building plans.
> The structural plans show that the size of the columns and reinforcements would have been typical for that time, and the roof would have had limited ability to redistribute the building’s load if one of the columns were to fail, he said.
> That could mean a failure in one column could bring down an entire structure, which could have been what occurred with this building, Mr. Leon said.
This is not an example of a random collapse. It is an example of what happens when you do absolutely everything wrong.
In West Seattle, they shut down the bridge from cracks, but it did take them a while.
>>Those taut tendons serve to push the concrete together like giant rubber bands. They help the concrete resist the gravity and other forces that could crack or otherwise pull it apart.
>>“In most cases [of] cracked concrete, you're not too bothered about the concrete not operating properly,” Stanton said. “You are worried about the steel inside becoming corroded.”
https://www.kuow.org/stories/city-has-known-about-cracks-in-...
Obviously great that they caught it and have a rapid response, but pretty crazy.
Whoever arguably had an unfulfilled duty. I’d say the condo association and its individual officers (who would have received the damage reports and arguably failed in their duty of care to owners and indirectly renters with regard to them) would be a good candidate. For renters or their families, their individual landlords would also be potential targets.
Indemnity tends to have limited scope, and whether a particular claim is within it is a question resolved in a lawsuit.
> They are just homeowners like everyone else
No, they aren't, because they are differently situated.
> unlikely to have any expertise in engineering or understanding engineering reports.
Special expertise is not required for culpabale negligence or culpable non-, mis-, or malfeasance. Whether, for instance, the reports they received provided sufficient notice of danger that they should, under the duty of carr applicable, have acted differently and their failure to so contributed to the harms to persons and property in the collapse is...precisely the kind of question resolved in a lawsuit.
> And possibly also now dead.
Death does not erase legal liabilities, generally. Its true that, after published notice of death, there is usually a limited time to file claims against the estate (which, with a live defendant, might have more time under applicable statutes of limitations, etc.) But that just adds urgency to identifying and acting on potential claims here, where, yes, some of the potential defendants might also have died in the event.
If this guy honestly felt that the building was at risk of imminent failure - which is what the media generally has been implying, it was not sufficiently communicated in the language used in the report, which fails to convey any sense of urgency. There is a whole bunch of pro-forma jargon, and pro-speak however, which seems to mask whatever its trying to say, and drains away the urgency from this.
So - yes, things hold up until they suddenly fall over.
It had more money budgeted for landscaping than actual replacement of anything structural (which was just 2500sqft of garage decking). Even that would probably better be described as waterproofing.
There was a lot of waterproofing, electrical, and HVAC work, as should be expected on a building that old.
But there was nothing in that proposal that would have done anything at all to prevent this.
The best case would have maybe been to uncover the real problems earlier, but most of the structural and waterproofing work was near the pool, which we know survived. So probably not.
It happens in buildings, it happens with electrical fire safety, it happens in healthcare (insurance and doctors largely don't believe in prevention in my experience).
Should have spent the money on actual improvements not cosmetic pool updates.
Changing a building's facade, cleaning up the entry area and gardens, but totally neglecting cooling systems and water systems (as examples of systems needing maintenance but with usually less-than-fatal consequences when neglected). It's very frustrating, and common to most (if not all) industries.
> The contractor visited the condo building last week to put together a bid for a cosmetic restoration of the pool as well as to price out new pool equipment — a small piece of the multimillion-dollar restoration project that just was getting underway at the 40-year-old building.
When lots of people have to agree on something, it's easier to batch everything up into one vote. It's the same reason we get giant spending bills in Congress instead of more focused ones.
I think maybe humans as a species aren’t so great at processing freak accidents. For some reason it’s easier to accept when we have someone to blame - real or imagined.
I can only think it is essentially impossible to get 20+ tenants to agree on something that involves them spending money, time, inconvenience, ...
> We have covered so much ground already to get the project rolling, it’s not surprising everyone is still asking about those items. Everything reviewed in this letter has been publicly presented, discussed, and voted on as necessary. We have discussed, debated, and argued for years now, and will continue to do so for years to come as different items come into play.
Sounds like you're not far off with your assumption. From the author's tone, it feels like he's annoyed.
So no you shouldn't interpret that as "about to fail".
Here is what I think I know:
When rebar corrodes it expands and that means even more air, water and salt can reach even further into the construction, meaning even more rebar is exposed and starts corroding. Edit: this probably weakens the concrete as well both because of exposure to the atmosphere and because of the cracking action but this last one is just an educated guess from my side.
How we worked was our foreman went first with an ultrasound device to detect the rebar and how much cover it had. He'd then sample the concrete by cutting into it, knocking out one side of the cut using a hammer and spray indicator fluid (I guess fenolftalein) on it. If the concrete turned pink it was healthy. You could measure how far out it was healthy.
If the measurements rebar was out in the damaged concrete we would expose it and apply protection before closing the wound. Sometimes we would also use a sledgehammer to adjust the rebar somewhat.
A number of factors influence how long concrete lasts before it needs maintenance:
- How far rebar is buried.
- The quality of the concrete as it leaves the mixer
- If the driver had lunch break or got stuck in traffic after loading the truck and added water to prevent anyone from noticing. Concrete starts curing immediately after mixing so you have limited time before it needs to be in the mould
- How well the concrete was vibrated to make sure it filled all gaps and that no significant air pockets was left
- How close you are to the sea
There's always someone on HN who knows something about everything and hopefully this was one of my turns to satisfy some of the curiosity for someone :-D
Edit: working with those older guys was really interesting. Seing a 70-year old bloke throw around tower lift parts that I figured I didn't have a chance of lifting. All the stories. The time I played with a bunch of cards and one of them askes to borrow it and started showing off crazy tricks; turned out he had a bronze medal from Nordic magic for juniors (and since he was now close to retirement and his hands were large and swollen I also got a chance to see what was really happening :-)
It was also the first place I know that actually practiced HSE. Others laughed but this team had 1-2% extra profit margin and I remember we got a nice bonus too. Ended up at around $15/hr which was close to twice what I used to get for much harder and dirtier work.
This was the spring of 2001. They liked me so when I left for school I got a nice job cleaning the work sites.
I’ve always wondered how many other buildings are in the same state.
But, if you’re looking for the business niche, I’d guess they’d be your customers. Basically a “bug bounty” program for underwriters of tenancy in common real estate.
https://www.sec.gov/news/press-release/2020-266
The SEC also has a whistleblower program that another commenter has linked and, as of recently, they have really been paying out a lot of money to whistleblowers. Larger sums and more frequent payouts than we’ve ever seen before.
[1]https://en.m.wikipedia.org/wiki/Qui_tam
[2]https://en.m.wikipedia.org/wiki/False_Claims_Act
POAs are a terrible idea and I wish they didn’t exist. Distributed ownership always seems to incentivize bad behavior.
What do you mean by "stability test holes kept failing inspection"? If you're referring to geotechnical boreholes, there's nothing to inspect - it's a test of (among other things) soil strength. It's certainly possible to have soft/loose/low-strength soils (soft/loose solis frequently cause the borehole to collapse on itself, that's not unusual) but that doesn't speak toward safety. The building just has to be designed & constructed to account for that, usually by stiffening the soil and/or using a pile foundation.
I’ve always wondered how many other buildings are in the same state.
Given the loose soils and relatively high-water table in Seattle? Pretty much all of them. Structures can be built on soft ground, it just needs to be done right.
Also, no, not referring to buildings on normal engineering. I’m talking about buildings built with corners being cut. This was also not in Seattle and wasn’t low lying, was on a hill.
But your friend's story doesn't make a lot of sense. The foundation would have been engineered for the soil that was there, not designed, then tested to see if the soil matched. Even cutting corners, it doesn't make sense to do the steps out of order. So I imagine there's more to the story.
Sometimes what is on site is not always what was in the report. And sometimes land nearby becomes unstable and retesting is required.
Also codes change on projects that take years. The current data center they are building gets changed to the prints almost daily.
of course you need piles deep enough, and boreholes soil test results probably factor into the decision of how deep it should be. The $100M fix for the tilting and sinking 58-story SF tower built in 2009 with "floating" piles not reaching the bedrock :
https://www.sfgate.com/news/editorspicks/article/SF-s-sinkin...
"The solution, likened to putting a bumper jack next to a flat tire, will involve the installation of 52 piles along the north and west sides of the tower. The piles will be beneath the sidewalk, 250 feet into the bedrock of downtown San Francisco, and be tied with the original 60-90-feet-deep foundation piles."
Soil stability and it's ability to support a building depends a lot on water situation.
reminded - back at University i worked summers on construction mostly doing foundations in Siberia in permafrost zone. The most memorable part of the quick introduction to the profession there was when they showed us several buildings which didn't have piles deep enough - most of those you could easily spot from a distance by the building shape defects like tilting, bended roofline, etc... because if piles aren't deep enough the foundation pretty much becomes really "floating" during warm season after several cycles of freezing/thawing.
Related, at a bigger scale, global warming affecting foundations in the permafrost zone https://www.theguardian.com/cities/2016/oct/14/thawing-perma...
One other situation I can imagine is that the risk is outside his domain. Example: I saw a company scrape flat clays out of a roadway and use that material as fill for slab-on-grade foundations of duplexes. I wouldn’t expect those to last long, but the developer is also the owner, so he’s only hurt himself. I don’t find the owner to be particularly sympathetic, I only certified the road construction, and the only person to report the poor practice to is the owner himself, who also hired the crew.
I guarantee you one thing - no matter the ultimate observable precursors, I bet there are thousands of buildings across the states that have the same precursors and nothing will be done.
Fundamentally maintenance is just not prioritized. This is true both in software and in general. If you want to scare yourself just Google elevator death. Elevators are a perfect example of the issue in that there are regular inspections but inspections do not imply maintenance.
I am not even sure how exactly you foster a culture of maintenance at this point.
I do have a new fear of drowning in an elevator, though: https://www.israelhayom.com/2020/01/05/young-couple-drowns-i...
I'm curious if it was a saltwater pool.
https://www.pentair.com/en-us/products/residential/pool-spa-...
https://www.miamiherald.com/latest-news/28th3w/picture252421...
Notice the feed line marked 'chlorine' on the wall, and it doesn't look like there's any salt chlorine generators in-line with the plumbing.
As long as the building is in a fancy neighborhood, this is not big news.
1. Almost anyone seeing all the warning signs probably didn’t think an entire building could collapse or partially collapse. Things could look terrible, but maybe not enough to say, “I need to get out of here before this building collapses.” Yes, that is said in old building and homes but it just doesn’t compute in building this size. That is why a professional inspector needed to be involved.
2. Time was also a problem here. In the US, a modern city with a 40 year old building just doesn’t compute. It’s actually kind of old in the US, especially with problems like this. Similar to #1, it didn’t compute a building this size could collapse this way. That is why a professional inspector needed to be involved.
>also, when performing any concrete restoration work, it is impossible to know the extent of the damage to the underlying rebar until the concrete is opened up. Oftentimes the damage is more extensive than can be determined by inspection of the surface.
from the HOA letter: https://s.wsj.net/public/resources/documents/miamiletter0628...
I suspect that some of the delay was due to the amount of work it took to get the huge special assessment lined up. It's likely that some of the residents who were killed had been fighting the condo association to avoid paying so much.
Here's a long letter that the condo board recently wrote to the unit owners about the concrete repair work.
https://s.wsj.net/public/resources/documents/miamiletter0628...
>that estimate indicated that the concrete damage observed would begin to multiply exponentially over the years, and indeed the observable damage such as in the garagehas gotten significantly worse since the initial inspection.When you can visually see the concrete spalling (cracking), that means that the rebar holding it together is rusting and deteriorating beneath the surface.Please note that the original scope ofwork inthe 2018 report has expanded. The concrete deterioration is accelerating. The roof situation got much worse, so extensive roof repairs had to be incorporated.
>Because so muchof the needed concrete/waterproofingwork is underground, we must pull up almost the entire ground level of the lot to access the areas that requirerepair. That means we have to put itall backat the end. This includes the pool deck, the entire entrydriveand ground level parking,north side contractor parking,and planters/landscaping. Electrical work and plumbingare involved almost everywhere. Balcony concreterequires repair/waterproofing,and the railingsrequire repair. And-we have to bring all this up to current codewhen repairs are completed.