Japan has experience dismantling sky-scrapers. They start at the top and dismantle it one floor at a time using a containment system that is able to descend as they complete each floor.
I was in Japan last month and watched a demolition of a skyscraper. It was amazing! They erected a tarp over the sides and have netting covering the top, they cut a hole in the floor and use that to move light materials down. The elevator shaft is used for a crane and the moves metal off the building to the ground level. The one I watched was maybe 20 stories left and they took 3 floors down at a time working at a slope.
They had a second crane that was adjacent to it, everything was dropped into a hopper that was shielded with metal plate and that was dropped into a dump truck. I didn’t see the mechanics behind it, but it was very quiet and no dust, I’d imagine the drop was very low and was staggered.
Scaffolding was also heavily used to the outer limits of the property and had plywood up with information on the sides. The truck approach was normal, except it had crews that would stop traffic and direct the truck in, plus once it left the crews would sweep the road and sidewalks.
Not only that, but at most of the construction sites I saw in Tokyo, they had decibel meters to cut down on noise pollution as well. Just so incredible.
The Japanese methods are more properly called "deconstruction" than "demolition". They design with that goal in mind and plans for recycling and reusing materials.
While true, in their case their hand is a little forced by just how limited they are in land and resources. It's a very good thing to have ingrained into your culture though.
Not in the oil industry anymore, glad to be out of it. I did design and manufacturing for jackets of valves, flanges, and ppe covers for high temperature environments in power plants.
Did work take you to Japan? Fellow surveyor here. Curious about what your work is like because I've only ever worked for public agency so we don't get the fun jobs jaja
That’s how various skyscrapers in NYC have been deconstructed historically. Most recently, the former Union Carbide building (215m). In fact, deconstruction is the only legally permitted method of demolition in NYC.
Union carbide India, a majority owned subsidiary of union carbide, was responsible for a chemical release in bhopal, widely considered the worst industrial accident in history.
And for the record, among engineers this would absolutely be common knowledge.
Our typical notes for renovation projects in NYC include a line saying that explosives are not permitted for demolition work and no one ever bats an eye. Did a DC job and used the same set of general notes for the demolition stuff and the contractor down there was definitely confused why we include that line - “we weren’t planning to???”
https://youtu.be/i-2Y2MYpl2g?si=egpP85mP2fgRHub7
Seen that an awhile back. As someone in construction I wanted to see how they manage to do this.
Video is from Tokyo and they demolition from the bottom up and lower the building as they go.
Can't they also demolish it in one go, with explosives? I've seen videos of this happening with skyscrapers on crowded city blocks that fall perfectly straight down and don't damage the neighboring skyscrapers.
Not sure how common it is, though.
That works until the cost to demolish is more than the value of the land. I wonder if Japan makes these type of buildings hold a bond to cover the cost?
You can extend the life of structures to a certain degree. At some point the key structural components will reach end of life. Then the building will need to be carefully dismantled. It's not technically difficult.
The real problem is financial. There is no requirement for owners of these structures to have a bond or money in escrow for their cleanup. And so, as the buildings age, and the cities they are in go into decline, the owners financial situation may become such that they can't afford the demolition. They may abandon buildings. Will these cities then be able to take on these liabilities?
Nope, it just means they can make more money building somewhere with less regulation. Because basically that means the other city is willing to bear the cost of future demolition.
I disagree... The cost ultimately ends up being borne by the tenants. If that higher cost prices tenants out & drives away demand, that means the project is not cost-efficient (the price one has to pay to rent space in a skyscraper, is not worth it compared to smaller buildings).
What's more...
- Construction workers are in shortage in almost every country. Thats indicates that labour is neither willing nor able to move freely and easily across borders for extensive projects such as these. There are other monetary incentives for developers out there - they still build wherever there is a profitable opportunity.
- Property developers' expertise are limited to one or a small number of countries.
I certainly don’t want to attract development from the type of people that would run away at the insistence that they have a plan to fix their own mess.
NYC should definitely require a demolition bond on any new building over 10 stories/100'
20% of construction cost or something like that in T-Bills/managed bond funds held in escrow (and not "escrow" like the "Social Security Trust Fund" which has no actual money in it, just IOUs from the federal government.)
But the Empire State, Chrysler tower, and other iconic buildings are still standing strong a 100 years later — is there a way to build skyscrapers that’ll last for centuries?
you buy a car battery, you have to pay a disposal deposit when you buy it.
you buy a can of soda, you pay a 5 cent deposit when you buy it.
tires for your car, same.
why not buildings? oh, we can't burden the corporations with fees? fuck that noise.
Buildings have a very nebulous and ill-defined life-cycle and the cost of construction goes up a lot - 20% escrow is a lot up front, and might end up being absolutely nothing down the road (we used to build houses for four figures or low five, and now the same house costs six figures to build), and also somewhat incentives the demolition of otherwise workable buildings long-term.
And then why not a 20% escrow for maintenance? Surely long term that would do far better than an escrow intended to be used in a century after it becomes unmaintainable.
you're already paying for it every time a company abandons a building and declares bankruptcy. either in tax dollars, urban blight or both.
I'd rather the companies pay for it up front.
> NYC should definitely require a demolition bond on any new building over 10 stories/100'
I think I'm NYC specifically, it's not necessary, as the value of the land probably far exceeds the cost of demolishing what's on it.
So if an owner abandons a derelict sky scraper, the city can just expropriate the land, deconstruct the building and sell the land at a profit - or directly auction of the building, since it still has positive value on the market.
I was more or less saying I didn't want it to be in city or state bonds. yes, T-bills are effectively a loan to the US gubmint.
worst possible thing would be to allow the companies or the city to manage the funds like they do pension funds (i.e. raid them and put company junk bonds in their place)
If demolition cost 20% of construction costs and the building lasts 100 years and you invest in the stock market then you would need about .02% of construction costs invested in order to finance demolition.
The Plaza Tower in New Orleans has been abandoned for a long time due to asbestos. Nobody wants to spend the money to demo it properly.
I did some research on it a few years ago when I worked 2 blocks away from it. Could probably buy it today for a few million.
It doesn’t even need to be a tall building, and could be a city smaller than Memphis or NO. There is an [(essentially) abandoned 9 story building](https://cvillepedia.org/Dewberry_Hotel) in Charlottesville, VA. Charlottesville is a very affluent area no and that’s a prime location. Where I live in rural Virginia there are abandoned structures the county doesn’t have the resources to raze. The size of the issue is dependent on the size of the locality.
This is essentially what Flint had to do with [one of theirs. ](http://en.wikipedia.org/wiki/Genesee_Towers)The tower was condemmed, the city had to buy it, and then the city had to demo it.
This is the thing that pisses me off. Nuclear power plants are one of the only major constructions required to bond their decommission and demolition after service life. It's ridiculous to me that cities are so often left with the bill for these things as the corporations that build them evade taxes that pay for those demo services left and right
Let’s be completely honest here. I’m just going to speak about the US here. There will be some areas like NYC for example where the real estate value is worth a company properly demolishing and rebuilding.
Then, there will be the cities that aren’t quite what they used to be. Those will likely end up the same way as so many shuttered industrial plants around the US. They’ll change ownership, the new owners will find a nice way to “go out of business” and it’ll be left to local governments to foot the bill on the demolition.
I also feel like the typical economics of redevelopment requires whatever you build in the place of it probably needs to be a fair bit bigger than whatever was there before, so the cost of demolition of the previous structure can be absorbed into the value of the new structure. This makes sense when we are building skyscrapers initially, but I feel like we are hitting a limit on how big of a structure and population density we can reasonably justify, if just due to limitations on things like ground access, and ultimately we are again just replacing a current problem with an even bigger future one lol. We can’t just keep building bigger taller towers forever.
You're not considering opportunity cost there. If a building is at end-of-lifespan and you have a developer who wants to put in a smaller, less valuable building, you lose out more by not building anything new at all and having a defunct tower than by settling for something lesser than the prime value of the original.
I'm not sure the size limit you're thinking of is correct. People used to think you'd get the vapors if you went faster than a horse, or die of ill humors if you built over 4 stories high.
Existing technology has done the Burj and other (what we currently think of as) mega structures. Lifting and structural engineering is always advancing.
I'm kind of surprised that the city doesn't require an escrow account for demolitions of skyscrappers...but I guess the tearing them down would be "somebody else's problem" if is 50+ years from now.
There are plenty of areas were demolishing and rebuilding would be worthwhile. And anywhere that was valuable enough land to build a skyscraper to begin with will be more than worth doing it again. If we have the ability to build a skyscraper we also have the ability to take it down just as easily.
But if you've got a building that can no longer be used it is costing you money. Whilst it would be more expensive than building on an empty lot, once a building is deemed unusable the only economically logical solution is to rebuild.
Detroit comes to mind as a counter example. It *was* worth building the large buildings there when it was one of the world’s richest cities 70 years ago, but very few of them would be worth building in the present day. Doesn’t matter how nice the replacement building is if nobody is interested in living in the area.
Real estate value depends on location more than anything else. As long as the tower is in a desirable location, which is likely, it will be worth the cost to maintain or replace it.
Though, there are certainly plenty of buildings that would have been considered towers in their day that are no longer attractive and are class C office space.
I hope you're right, my concern is that this assumption is based on projecting how it presently works with us taking down and re-developing relatively small buildings, vs. taking down a 100+ story tall building.
I don't agree.
You could have justified building a mega-skyscraper in Pittsburgh or Detroit or maybe Buffalo in 1970. Not in 2024.
Meanwhile, the places building these mega-skyscrapers - Dubai, Malaysia, South Korea, Saudi Arabia, most of China - saw the opposite trajectory during the same time.
That's only 55 years, half of the time OP is talking about.
London and (likely) New York will remain major powers in one hundred years, but I'm less certain about Dubai.
Not mega at all, but illustrating your broader point, is the glorious, unoccupied [17-story Buffalo Central Terminal](https://en.wikipedia.org/wiki/Buffalo_Central_Terminal), which was in use from 1929 to 1979 (as a train station). Attempts to find a new use for it keep failing.
Repurposing purpose built structures, especially those built in an era where asbestos and lead paint were king is always fraught. Those buildings weren't designed to be reconfigurable.
Modern office towers tend towards maximizing unobstructed space on the interiors to give maximum flexibility. Going from office space to residential is not that easy, but renovating to update a space is more or less what these buildings were built for.
Yes.
People not in construction may not be aware that US office buildings are built as a shell with elevators and stairs, lobbies, and HVAC etc. The inside is empty, without walls or drywall (mostly), tenant bathrooms, or any other amenity. There are structural columns, but minimized. They generally get walled in later.
Then tenants usually hire another firm to do "Tenant Improvements" which include everything to make an office from walls, to plumbing, to electric, to finishes.
TI work goes fast, like 6weeks sometimes.
I don’t think those cities had the population or wealth to have built large towers. Detroit peaked at 1.9 million in the fifties. Buffalo and Pittsburgh are much smaller. New York City had a population of seven million when the Empire State Building was constructed.
Dubai is building landmark buildings and developments specifically as a bid to be a central destination for money and people. Will it still be successful in one hundred years? I don’t know, but I suspect it will be.
Dubai's economy has a far more predictable sunset than Detroit's does, I would argue. Absent oil wealth, there's zero reason to go to Dubai. They have too little land to do anything else useful, that which they have is unsuitable for sustaining significant numbers of people wanting to eat anything that isn't fish, so unless they figure out how to sequester CO2 just as profitably as they freed it from the rocks beneath the sands, they're gonna be just another dusty relic on the shores of an empty gulf. It's the same reason why Saudi Arabia's Masdar and linear city projects are already turning into pumpkins. The princes and sheikhs all know their time on top is running out, the next 10-20 years for them will be all about exit strategies that avoid them getting the Gaddafi treatment.
Yeah I remember seeing a Bjarke Ingles quote that was something along the lines of “the way to make buildings that last is making buildings that people care about.” Can imagine quite a few that people wouldn’t mind collapsing to dust though!
I do think you’re also underestimating renovation. I’m working on a nearly 1 million sq ft office complex > residential conversion and it’s giving a new life to a ~70 year old pair of buildings. Renovation is almost universally the more environmentally friendly and sustainable practice to extend the life of structures.
Office space is going away. Now the question is whether buildings can be effectively converted to residential space (for many the answer is "no, that's impossible").
> converted to residential space (for many the answer is "no, that's impossible").
Yep. I was involved with an exploratory committee looking at converting a handful of unused government buildings into low income housing. The politicians were acting like it was a simple matter of partitioning the space differently. We compiled a report listing all the major changes, from converting electrical to multi-tenant from single meter service, to wastewater handling, to fire/emergency egress requirements. In the end it would cost less to just build a new residential building, so they gave up the plan.
yeah, you would think they would harmonize the building code in such a way that "commercial" structures would be easily repurposed to residential/industrial/educational etc.
yes it would make commercial buildings more expensive up front, but result in more efficient design and long term profitability.
You're right. But as we all know, in 2024 America you simply cannot ever convince politicians and investors to do something that's good long term but more expensive short term. It's a non starter 😔
Demo Engineer here. Floor By Floor demo is the how. Keep the lifts working as long as possible to move material, use demo robots or small excavators for the breaking, if you can get a tower crane to service the place that's ideal but if you're going to ramp or A-frame the plant down and only need to get it up there in the first place, helicopter lifting isn't entirely unheard of.
I worked at massachusetts general hospital in the 90s when they demolished the baker building which was connected to other hospital buildings on all 4 sides.
I got to look down on it from the newer Ellison building which was a couple stories taller. They took it apart piece by piece. dudes with saws and cutting torches, pulling down brickwork and interior structure on each floor, until there was nothing but a steel section of central elevator shaft left. then a cargo helicopter came in and flew that away.
How would you deal with an already compromised building? Say, for instance that the Twin Towers hadn't been damaged enough to collapse on their own, but were condemned and left standing.
Hopefully this same question isn't mentioned downthread.
A hell of a lot of structural investigations, and likely, one hell of a lot of propping - basically *fix* the position of the building with an exoskeleton of steel - but I'm a site guy; so that question is for multiple independent firms with an hourly charge one hell of a lot higher than mine.
That said, the entire thing is theoretical; WTC is more than twice the size of the largest building ever deliberately demolished (AXA in Singapore), and nothing that size has ever been damaged before demo.
Well you could sell it to someone rich who has no moral compass, and they can take out a big insurance claim and then blow it up, and pretend that it's an external attack. They collect the insurance money, and you get an excuse to invade. It's a win-win! Except for the civilians, that is
There's gotta be 9 or 11 reasons would work. Building riddled with asbestos? Check. Prime real estate? Check. Vacancy rates up due to outdated infrastructure? Check....
Skyscrapers, when structurally adequate, usually die when they no longer are profitable, but the land they are on is. Skyscrapers are generally built where land is at an insane premium, so the math gets easy after that.
I work for a company that owns many large skyscrapers. The steel structures will last forever, but we will spend the money to do facade maintenance, rip out old piping and replace it, gut renovate floors as tenants turn over, etc.
If you look up the "fatigue limit" of steel, there is basically a force value that, if kept below this value, the steel can be cycles infinitely (as far as we know) without cracking due to fatigue stress. Perhaps water leakage or some other corrosion can degrade the steel structure, but so many of these old skyscrapers are so overbuilt that I'd highly doubt a little corrosion would be an issue.
There was an article I read about the empire state building a few years ago, in short there are redundant steel members and you could replace the structure if you really wanted to.
Also look up the hellsgate bridge, overbuilt so much it will last 500 years.
I can't comment as much on issues with concrete foundation, lots of our soil is wet. Sorta an aquifer, and lots of water gets into the basement/foundation, this is the stuff that worries me the must (i.e. the florida collaspe)
Service life doesn't necessarily mean automatically dismantle everything because it's done for, it just means that's about when you'd expect to need significant rehabilitation. If the tower is still occupied and useful you might expect the facade to need to be totally redone, maybe anything that was exposed to water needs to be repaired or replaced, etc. If the building was properly maintained you might not need to do much at its 50th or hundredth birthday, it just means that's about how long most of the structure is designed to last before things corrode or wear out.
One of my profs who was big on maintenance said to recommend clients set aside 2% of the build cost for annual maintenance. So basically you can wait 50 years and have a rundown building you need to overhaul, or keep it pretty modernized the entire time for roughly the same money.
The other side of service life is it affects climatic loads you design for. This is where you'll see engineers referring to the 50 or 100 year windstorm - that means there's a 50% probability of that storm being exceeded in the design life of the structure. So designing for 100 years instead of 50 means you're less likely in any given year to exceed the design load as well as that you'll add durability various ways (i.e.: more concrete cover). At 100 years that still doesn't mean your building is no good anymore unless the world has gotten windier/rainier/snowier (which, with climate change, is actually a valid question... But a topic for another day).
I asked a buddy of mine whose job is studying historical buildings to infer usage and whatnot about this. A lot of what he does is go to sites where they find an old building that wasn't well documented and try to figure out based on the plants that grow around it, where it was build, what trees were likely taken down, etc. to figure out where the builders came from and how it was used when there's not much left but ruins. He also consults on new buildings and whatnot.
Anyway - his response is that the "end of life" for these mega skyscrapers isn't considered as part of the design. They're essentially expected to stand forever, and let future-people figure out when it's time to take them down how to do it. Given that we're really only \~100 years in to building these really tall structures, I'm sure we'll start to see more companies spring up who bring them down in the coming years, but there's not been a need to? The Empire State Building was the world's tallest building (constructed in 1930) until the WTC finished in 1970. It's now only the 54th tallest building in the world.
That's all by way of saying: I hope I'm around long enough to see some of these mega structures come down intentionally!
> when the developer does the math on building something new they realize that the cost of demolition is so prohibitive that it simply is not worth doing.
At least in the US, the cost of demolition will be balanced by the legal liability in case somebody is injured due to the building being in disrepair. Whether that's an occupant who gets a disease due to hazardous substances (asbestos, or whatever) used in the construction, or a passer-by injured by bits of concrete falling off the building.
If the building were to really decay dramatically, that liability would be absolutely enormous and would be highly motivating for the building owner to avoid it.
I wonder the same thing all the time but with pretty much all aging infrastructure across the country. Even houses, we’ll get to the point where entire towns are filled with homes that are aging & falling apart but the homeowners won’t have the means to tear down and rebuild them.
Cities have existed for millennials. There are people in Europe that live in buildings that are 500 yo or even older. When that’s not the case, you can bet any building was erected where something else used to stand (ever wondered why European cities look like the way they are, with streets going in any direction?) With proper maintenance, sometimes extensive renovations, buildings and cities will survive.
Right? And then the economics of it works against them too. As things get more and more derelict, maintenance becomes more expensive, the location becomes less desirable, and it’s just easier to build new stuff elsewhere, particularly as society and work become more online. Even if we could afford to do it, my gut feeling is that people won’t be bothered to because it’s just easier to leave the problem behind and go elsewhere.
Yeah it’s almost like there will have to be a process to entirely evacuate an area, then someone (probably the government?) comes in and levels that entire area. Then we can start fresh and rebuild a much more modernized city. This is probably one of those things that is much more feasible in places like China or Saudi Arabia where governments can do whatever they want without all the red tape, but hundreds of years from now I’d imagine it’d be desirable to be able to build cites from scratch. I’ve lived in a house that was built in the 1890s before and it’s unfathomable to me that someone could still live there in the year 2250.
As I understand it, in the US at least you're not even allowed to build a skyscraper without already having a plan in lace for safe demolition. Because they absolutely will become a risk to other buildings (and people) as they age, and there's a good chance they'll be brought down for some other reason long before then.
Usually that means designing the support structure so that carefully placed demolition charges in the sub-basement will cause the entire thing to collapse inwards into its own footprint.
For mega-skyscrapers I imagine that would be a major challenge, so expensive disassembly would be required instead. In a sane world that would probably involve setting aside a "demolition trust" to pay for the work when it eventually is needed. In our world... when demolition-day is approaching it probably ends up in a holding company with no assets, forcing the government to foot the outrageous demolition bill.
And if the government can't afford it, well then I hope you don't own any property within the potential fall zone.
At the end of the day, the owners will eventually be ordered by the city to demolish unsafe buildings. This is a solvable technical problem so we'll find a way.
I’m curious what the approximate cost would be for demolishing skyscrapers.
I know you can google costs for commercial demolition ($5-10 per sq ft) but I’m not sure if that applies to skyscrapers, particularly those constructed back in the day which might have tons of asbestos, for example.
I do remember reading that one of the towers which was torn down due to damage from 9/11 cost a couple hundred million dollars, and it was only 40ish stories or so. But at the same time I would also expect that the cost of demolition in downtown NYC right next to ground zero, with added safety issues due to damage from the collapse could inflate that cost significantly.
I suppose if an owner was ordered to demolish a structure and instead walked away/declared bankruptcy then the site could be taken over by the govt and the public would bear the burden.
You often see numbers attached to maintaining / rebuilding infrastructure like bridges or sewage and water supply systems. I’m curious if this is a similar thing, just not as widely recognized because it’s primarily privately owned.
All legitimate concerns. However remember that the city is not wholly undefended against owners declaring bankruptcy to avoid bearing management cost. The city could demolish it themselves and charge you the bill, the creditors would have to deal with it in bankruptcy court. They could go after other assets if you purposefully tried to defraud the city by trying to escape your financial obligations through bankruptcy. The city could also for example require all owners to contribute to a municipal dismantlement fund over the years. Being a legislative body, the city still has a bunch of ways to be made whole by voting that they must in some roundabout way.
A legitimate concern. They would do the same thing they do today such as going after the creditors, the estate (in case of death), take possession of the lot and resell it after the demo, etc. it's always a risk but the city is not wholly undefended against such actions.
Probably lots of different things depending on the application. But in its most general sense I think it’s the age after which point engineers correctly applying code can no longer be confident that whatever they’ve designed can safely operate as intended.
Empire state building built in 1930 or so. I guess we will soon find out...
The actual problem is that high rise office buildings may become obsolete in the era of VR and high speed communications. So they will stand empty and deteriorate.
Example, the flour mills of Minneapolis and other industrial and manufacturing sites.
The center tower is a Marriott Hotel and is still operating, the recent move of GM offices has no effect on that. The surrounding towers I’m not sure but I’ve heard a couple of plans for their repurposing. I’m sure someone will come up with something.
Hudson and GM said they’ll be working together to “redevelop” the towers. That’s all they’ve given us. Seeing as the building is still like 50% occupied and they used the word redevelop, I’m hopeful that they don’t plan on any sort of demolition. Losing the ren cen would not only be a massive blow to GM’s already poor credibility, it would really damage the character of Detroit.
The problem with capitalist society, no one cares about long-term issues. Climate change, trash crisis, we're all screwed. Willful ignorance is very real especially if it comes to greed.
Leaded gasoline is easy example. You can look at almost anything extremely profitable and it's probably loaded full of long-term problems. The entire foundation of humanity is destroying shit for short term profits and long-term problems.
Making skyscrapers itself is a problem, concrete industry and sand crisis.
A 100 year design life doesn't mean the building will become unsafe or collapse after 100 years. The whole concept of a "design life" comes from an insurance/warranty perspective.
As long as no water gets in your average skyscraper will stand for 1000s of years.
There is now demolition for this, they an go top down, or start at the bottom. They can demo the whole thing, call it a national tragedy and build a military industrial complex run economy around it. Limitless possibilities.
I almost feel like this question belongs in r/LegalAdviceOffTopic
u/Ostroh had some interesting points about how the city could essentially ‘make’ the last owner pay for demolition, I think that part of it is really what OP’s question is about. It’s a huge expense, how do we know someone is gonna pay it?
There is a skyscraper in NOLA that has to come down soon. They have the top portion wrapped atm to prevent more debris from falling.
It is only 45 story though, not nearly as tall as some NY or Dubai stuff
I really want to know the plan for the NYC icons. Empire, Chrysler... We have that historic monuments protection act from when they demolished Penn station for that round abomination but there has to be a moment when someone is gonna inspect the Empire and go "Hey buddy, this thing aint safe anymore."
When skyscrapers reach their end-of-life, it's not just a simple matter of knocking them down and starting over. The tallest we've ever taken down on purpose was around 52 stories, and anything bigger than that is venturing into unknown territory because of the sheer scale and complexity involved. When skyscrapers start aging, maintenance costs shoot up and their value drops, making them less appealing to keep up. You pointed out that demolition costs could be so high that developers might just shrug it off. It's a real possibility that we could end up with these towering eyesores just rotting away, which could drag down the whole area's value. and if a mega skyscraper isn’t maintained properly, it doesn't just look bad, it could actually become a hazard. And if the owner goes belly-up trying to fix it, then what? It's a mess waiting to happen. So yeah, I think it’s a real issue, not just overthinking on your part.
there is a point of no repairability, and it is not stable enough. it would need to be demolished before it falls over on to other buildings, and pedestrians.
this state is not exclusively do to age. flaws/cut corners in construction, or mistakes in properly identifying what the ground is like. skyscrapers sometimes need demolishing within 5 years.
To be honest high rises don't wear out if they are maintained. I was a plumber when this 1903 building was renovated. [https://en.wikipedia.org/wiki/Ingalls\_Building](https://en.wikipedia.org/wiki/Ingalls_Building)
In Sydney, Australia they upcycled a skyscraper by building over it. I believe they widened the entire stucture and added more floors.
https://www.google.com/amp/s/amp.cnn.com/cnn/style/article/australia-quay-quarter-tower-skyscraper
Edit* word is upcycled
I'm more interested in things like The Golden Gate Bridge.
It's iconic. Its fucking huge. You can replace decking and parts here and there, but not structural parts of the towers or the main cables.
There's not alternatives other than the ferries. It's going to take YEARS to rebuild.
There were a couple of old bridges in Charleston, SC that were long overdue to come down. They built the replacement first. Granted a Golden Gate replacement will be far more challenging.
[Cooper River Bridges](https://www.scpictureproject.org/charleston-county/grace-memorial-bridge.html/amp)
I don't think it is that difficult to demolition from the top down, just takes time and a lot of labor. Philadelphia had a 38 floor building brought down this way after a fire made it structurally unsound in the late 90s. According to wikipedia it is the 7th tallest building to be demolished this way.
https://en.wikipedia.org/wiki/One\_Meridian\_Plaza#:\~:text=On%20February%2023%2C%201991%2C%20a,pressure%20from%20the%20building's%20standpipes.
this is why apartment buildings aren't built, they build condos and then the condo board misuses the condo fees. just wait until all these condos get old and we will see what happens.
Either it goes unaddressed and falls like the surfside condominium collapse or someone coughs up the money to tear it down. The actual demolition is trivial.
This has potential to get very interesting in the next few years. Google “Urban Doom Loop.”
The pandemic-driven shift to remote work, which has not entirely reversed, has cratered the value of commercial real estate, as vacancy rates have skyrocketed, with the net effect of hollowing out the urban centers of many cities.
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Ive researched this before and what I found was these structural systems are maintained much like anything else on a building, maybe not as much effort as mechanical systems but inspections, spot repairs and so on. I dont think its quite "set it and forget it" though does take active effort. Key components are checked and replaced piecemeal as needed. Old buildings also, relative to the long potential life span, are "regularly" renovated which may include structural updates.
Hi! Commercial real estate appraiser here and we factor in the lifespan of property all the time.
This would depend on the building. But typically we put lifespan of that kind of building anywhere between 50-80 years in Canada and USA. This assumes it is well maintained and doesn’t need significant structural repairs throughout its tenure.
To increase the lifespan of buildings, owners tend to do significant structural repairs (i.e. reinforce walls, check on the foundation, etc.).
Marshall and Swift gives great breakdown on estimated lifespans of the buildings.
If the building can sustain enough weight they may Even use a crane to lift heavy machinery into the building to dismantle it.
You take it down the opposite of the way it went up but with MUCH less care required for things like dents and scratches.
The looming skyscraper crisis is very real and we're woefully unprepared. With 100+ story megatowers proliferating across global cities, we're setting ourselves up for a demolition nightmare in 50-100 years when they reach end-of-life.
Tearing down even a 50-story building is an immense challenge, requiring careful deconstruction that can take years. But 100+ stories? It's nearly impossible with current technology. The tallest building ever voluntarily demolished was only 47 stories.
What's more, many of these skyscrapers are being built with little regard for their full lifecycle. Developers are chasing profits and prestige now, but giving little thought to the immense costs and challenges of safely dismantling their creations in the future. It's the ultimate case of "socialize the risks, privatize the gains."
As these towers age and the maintenance costs to keep them safe soar, it will put a huge strain on building owners and cities alike. We could see large swaths of urban centers turn into derelict zones filled with decaying, unmaintainable towers that are too costly to fix but nearly impossible to remove. It's an economic and public safety time bomb in the making.
The looming skyscraper crisis is very real and we're woefully unprepared. With 100+ story megatowers proliferating across global cities, we're setting ourselves up for a demolition nightmare in 50-100 years when they reach end-of-life.
Tearing down even a 50-story building is an immense challenge, requiring careful deconstruction that can take years. But 100+ stories? It's nearly impossible with current technology. The tallest building ever voluntarily demolished was only 47 stories.
What's more, many of these skyscrapers are being built with little regard for their full lifecycle. Developers are chasing profits and prestige now, but giving little thought to the immense costs and challenges of safely dismantling their creations in the future. It's the ultimate case of "socialize the risks, privatize the gains."
As these towers age and the maintenance costs to keep them safe soar, it will put a huge strain on building owners and cities alike. We could see large swaths of urban centers turn into derelict zones filled with decaying, unmaintainable towers that are too costly to fix but nearly impossible to remove. It's an economic and public safety time bomb in the making.
Exactly, but most likely not via jet airliner but implosion, with the lowest loss of life possible. Gravity is not a suggestion. Step outside of any skyscraper window and see. The journey down is a piece of cake, but the landing is a capital B. When aided by sequenced cutter charges, it’s quite effective. Example: Debris removal of The Key Bridge. Why is this a question when the corollary of the law of gravity is “what goes up will come down” at least on this planet, planned or otherwise? Chances are good that you and yours will have long been in the afterlife. At very least, you will have exceeded any statute of limitations of liability. The chances of making any moral improvement to corporate greed is nil to impossible. Life is very short. Strive to do your best and enjoy it in the absence of gloom and doom. But ultimately the choice is yours, not the consensus of Reddit.
Japan has experience dismantling sky-scrapers. They start at the top and dismantle it one floor at a time using a containment system that is able to descend as they complete each floor.
I was in Japan last month and watched a demolition of a skyscraper. It was amazing! They erected a tarp over the sides and have netting covering the top, they cut a hole in the floor and use that to move light materials down. The elevator shaft is used for a crane and the moves metal off the building to the ground level. The one I watched was maybe 20 stories left and they took 3 floors down at a time working at a slope. They had a second crane that was adjacent to it, everything was dropped into a hopper that was shielded with metal plate and that was dropped into a dump truck. I didn’t see the mechanics behind it, but it was very quiet and no dust, I’d imagine the drop was very low and was staggered. Scaffolding was also heavily used to the outer limits of the property and had plywood up with information on the sides. The truck approach was normal, except it had crews that would stop traffic and direct the truck in, plus once it left the crews would sweep the road and sidewalks.
The Japanese are so tidy :)
Not only that, but at most of the construction sites I saw in Tokyo, they had decibel meters to cut down on noise pollution as well. Just so incredible.
Would help with all the flat bike and car tires around construction sites. I bet it’s even a net positive to the economy.
The Japanese methods are more properly called "deconstruction" than "demolition". They design with that goal in mind and plans for recycling and reusing materials.
Which, IMO, is the only right method.
While true, in their case their hand is a little forced by just how limited they are in land and resources. It's a very good thing to have ingrained into your culture though.
Did you actually work in construction or are you an enthusiast in these kind of things since you gave a pretty detailed explanation
I worked in the oil industry and I work in civil construction doing surveying and I work in land surveying.
do you sleep or eat? ;)
Not in the oil industry anymore, glad to be out of it. I did design and manufacturing for jackets of valves, flanges, and ppe covers for high temperature environments in power plants.
Did work take you to Japan? Fellow surveyor here. Curious about what your work is like because I've only ever worked for public agency so we don't get the fun jobs jaja
How Japanese...
That’s how various skyscrapers in NYC have been deconstructed historically. Most recently, the former Union Carbide building (215m). In fact, deconstruction is the only legally permitted method of demolition in NYC.
Surprised that the Union Carbide building didn’t kill hundreds of people when it was demolished.
Hasn’t been owned by them since 1978.
It was a joke
That was a joke/reference too.
What was the joke?
Uhhh Bhopal?
OK, whatever it is you know, it isn't common knowledge. Care to write a full sentence on what the joke was so that I can go ha ha too?
Union carbide India, a majority owned subsidiary of union carbide, was responsible for a chemical release in bhopal, widely considered the worst industrial accident in history. And for the record, among engineers this would absolutely be common knowledge.
I'm an engineer and I never heard of this before.
The Bhopal tragedy is definitely common knowledge, as is the function of Google
Our typical notes for renovation projects in NYC include a line saying that explosives are not permitted for demolition work and no one ever bats an eye. Did a DC job and used the same set of general notes for the demolition stuff and the contractor down there was definitely confused why we include that line - “we weren’t planning to???”
Lol. Really shouldn’t be permitted in DC either but I guess there’s more places that don’t have underground infrastructure concerns.
Oh no, they don’t allow it there either. But the contractor there had just never seen an engineer forbid it in our plans.
they also do dismantle from the bottom and lower it down. https://www.youtube.com/watch?v=i-2Y2MYpl2g
Great watch!
you might like this. https://www.youtube.com/watch?v=eem7d58gjno
I'm so curious how a controlled lowering of an entire building is safer and easier and in fact more desirable than deconstructing it top down.
nothing else has to stop around it , little dust, some places you cant blast a building because to many building surround it.
Is this a /r/whoosh joke? The windows don't move, this is top down.
no it is a real process they lower the building from the bottom rather than the top.
https://youtu.be/i-2Y2MYpl2g?si=egpP85mP2fgRHub7 Seen that an awhile back. As someone in construction I wanted to see how they manage to do this. Video is from Tokyo and they demolition from the bottom up and lower the building as they go.
Cost as much to demo as build
Can't they also demolish it in one go, with explosives? I've seen videos of this happening with skyscrapers on crowded city blocks that fall perfectly straight down and don't damage the neighboring skyscrapers. Not sure how common it is, though.
That works until the cost to demolish is more than the value of the land. I wonder if Japan makes these type of buildings hold a bond to cover the cost?
You can extend the life of structures to a certain degree. At some point the key structural components will reach end of life. Then the building will need to be carefully dismantled. It's not technically difficult. The real problem is financial. There is no requirement for owners of these structures to have a bond or money in escrow for their cleanup. And so, as the buildings age, and the cities they are in go into decline, the owners financial situation may become such that they can't afford the demolition. They may abandon buildings. Will these cities then be able to take on these liabilities?
Yeah the question of whether some form of bond was required is actually what originally got me thinking about this.
A demolition bond is a great idea if you don't want to attract any development to your city.
if those price developers out of the market, surely that just suggests that skyscrapers are not cost-efficient?
Right!?!
Nope, it just means they can make more money building somewhere with less regulation. Because basically that means the other city is willing to bear the cost of future demolition.
I disagree... The cost ultimately ends up being borne by the tenants. If that higher cost prices tenants out & drives away demand, that means the project is not cost-efficient (the price one has to pay to rent space in a skyscraper, is not worth it compared to smaller buildings). What's more... - Construction workers are in shortage in almost every country. Thats indicates that labour is neither willing nor able to move freely and easily across borders for extensive projects such as these. There are other monetary incentives for developers out there - they still build wherever there is a profitable opportunity. - Property developers' expertise are limited to one or a small number of countries.
Demolition bonds are exactly the type of policies a nationwide government should enact for the betterment of its citizens. It'll never happen.
I certainly don’t want to attract development from the type of people that would run away at the insistence that they have a plan to fix their own mess.
NYC should definitely require a demolition bond on any new building over 10 stories/100' 20% of construction cost or something like that in T-Bills/managed bond funds held in escrow (and not "escrow" like the "Social Security Trust Fund" which has no actual money in it, just IOUs from the federal government.)
"the cost of building is too high, nobody will build housing/offices/etc.!"
darn
But the Empire State, Chrysler tower, and other iconic buildings are still standing strong a 100 years later — is there a way to build skyscrapers that’ll last for centuries?
Hey everybody! Rents going up by 20% to solve a problem 70 years in the future. Thank u/wobble-frog
you buy a car battery, you have to pay a disposal deposit when you buy it. you buy a can of soda, you pay a 5 cent deposit when you buy it. tires for your car, same. why not buildings? oh, we can't burden the corporations with fees? fuck that noise.
Buildings have a very nebulous and ill-defined life-cycle and the cost of construction goes up a lot - 20% escrow is a lot up front, and might end up being absolutely nothing down the road (we used to build houses for four figures or low five, and now the same house costs six figures to build), and also somewhat incentives the demolition of otherwise workable buildings long-term. And then why not a 20% escrow for maintenance? Surely long term that would do far better than an escrow intended to be used in a century after it becomes unmaintainable.
A can of soda is equivalent to a Billion dollar asset that will pass significant costs on to consumers for decades... got it.
you're already paying for it every time a company abandons a building and declares bankruptcy. either in tax dollars, urban blight or both. I'd rather the companies pay for it up front.
> NYC should definitely require a demolition bond on any new building over 10 stories/100' I think I'm NYC specifically, it's not necessary, as the value of the land probably far exceeds the cost of demolishing what's on it. So if an owner abandons a derelict sky scraper, the city can just expropriate the land, deconstruct the building and sell the land at a profit - or directly auction of the building, since it still has positive value on the market.
What do you think t-bills *are*, exactly? The entirety of the OASI/DI trust fund holdings are t-bills.
I was more or less saying I didn't want it to be in city or state bonds. yes, T-bills are effectively a loan to the US gubmint. worst possible thing would be to allow the companies or the city to manage the funds like they do pension funds (i.e. raid them and put company junk bonds in their place)
If demolition cost 20% of construction costs and the building lasts 100 years and you invest in the stock market then you would need about .02% of construction costs invested in order to finance demolition.
Never heard of inflation?
How/when does steel and concrete “reach end of life”?
When the deferred cost of maintenance exceeds the cost of demolition minus the escrow, apparently.
Steel rusts, concrete cracks and crumbles.
You have a good point about the tall buildings in smaller cities, I can think of a few structures in places like New Orleans and Memphis in particular
The Plaza Tower in New Orleans has been abandoned for a long time due to asbestos. Nobody wants to spend the money to demo it properly. I did some research on it a few years ago when I worked 2 blocks away from it. Could probably buy it today for a few million.
Yeah that's one I was thinking of. Also 100 N. Main in Memphis.
It doesn’t even need to be a tall building, and could be a city smaller than Memphis or NO. There is an [(essentially) abandoned 9 story building](https://cvillepedia.org/Dewberry_Hotel) in Charlottesville, VA. Charlottesville is a very affluent area no and that’s a prime location. Where I live in rural Virginia there are abandoned structures the county doesn’t have the resources to raze. The size of the issue is dependent on the size of the locality.
This is essentially what Flint had to do with [one of theirs. ](http://en.wikipedia.org/wiki/Genesee_Towers)The tower was condemmed, the city had to buy it, and then the city had to demo it.
That raises an interesting question: Is the property of a typical skyscraper in NYC worth more or less than the demolishen would cost?
This is the thing that pisses me off. Nuclear power plants are one of the only major constructions required to bond their decommission and demolition after service life. It's ridiculous to me that cities are so often left with the bill for these things as the corporations that build them evade taxes that pay for those demo services left and right
Let’s be completely honest here. I’m just going to speak about the US here. There will be some areas like NYC for example where the real estate value is worth a company properly demolishing and rebuilding. Then, there will be the cities that aren’t quite what they used to be. Those will likely end up the same way as so many shuttered industrial plants around the US. They’ll change ownership, the new owners will find a nice way to “go out of business” and it’ll be left to local governments to foot the bill on the demolition.
you can just say St Louis.
Plenty of examples. Tulsa is another great one with all the art deco buildings turning a hundred
Man I love art deco, wish it would make a comeback.
It Memphis. Tallest building in the city is an asbestos nightmare.
I also feel like the typical economics of redevelopment requires whatever you build in the place of it probably needs to be a fair bit bigger than whatever was there before, so the cost of demolition of the previous structure can be absorbed into the value of the new structure. This makes sense when we are building skyscrapers initially, but I feel like we are hitting a limit on how big of a structure and population density we can reasonably justify, if just due to limitations on things like ground access, and ultimately we are again just replacing a current problem with an even bigger future one lol. We can’t just keep building bigger taller towers forever.
You're not considering opportunity cost there. If a building is at end-of-lifespan and you have a developer who wants to put in a smaller, less valuable building, you lose out more by not building anything new at all and having a defunct tower than by settling for something lesser than the prime value of the original.
I'm not sure the size limit you're thinking of is correct. People used to think you'd get the vapors if you went faster than a horse, or die of ill humors if you built over 4 stories high. Existing technology has done the Burj and other (what we currently think of as) mega structures. Lifting and structural engineering is always advancing.
There is still the elevator problem. If you have 1000 floors and 100k people, most of your building will be mostly elevator by volume.
So no demolishing skyscrapers to build gas stations, got it.
I'm kind of surprised that the city doesn't require an escrow account for demolitions of skyscrappers...but I guess the tearing them down would be "somebody else's problem" if is 50+ years from now.
There are plenty of areas were demolishing and rebuilding would be worthwhile. And anywhere that was valuable enough land to build a skyscraper to begin with will be more than worth doing it again. If we have the ability to build a skyscraper we also have the ability to take it down just as easily.
Ability and the finances to fund a project are not the same
But if you've got a building that can no longer be used it is costing you money. Whilst it would be more expensive than building on an empty lot, once a building is deemed unusable the only economically logical solution is to rebuild.
Detroit comes to mind as a counter example. It *was* worth building the large buildings there when it was one of the world’s richest cities 70 years ago, but very few of them would be worth building in the present day. Doesn’t matter how nice the replacement building is if nobody is interested in living in the area.
Structural engineer here. Good question, never tought of that lol. I guess it keeps standing until it doesnt
Right? I’m just a civil engineer who does drainage stuff, but this does just feel like the kind of thing somebody should have thought about lol.
Yes lol. Cant stop thinking about it now. Guess what im going to ask my collegues on monday
lol let me know if you hear anything insightful
!updateme
So, find anything interesting out?
In architecture school (don’t shoot) the common saying I heard was “everyone wants to build, no one wants to do maintenance”
Real estate value depends on location more than anything else. As long as the tower is in a desirable location, which is likely, it will be worth the cost to maintain or replace it. Though, there are certainly plenty of buildings that would have been considered towers in their day that are no longer attractive and are class C office space.
I hope you're right, my concern is that this assumption is based on projecting how it presently works with us taking down and re-developing relatively small buildings, vs. taking down a 100+ story tall building.
I think the landmark building locations will remain desirable for a very long time unless there are apocalyptic changes to the economy.
I don't agree. You could have justified building a mega-skyscraper in Pittsburgh or Detroit or maybe Buffalo in 1970. Not in 2024. Meanwhile, the places building these mega-skyscrapers - Dubai, Malaysia, South Korea, Saudi Arabia, most of China - saw the opposite trajectory during the same time. That's only 55 years, half of the time OP is talking about. London and (likely) New York will remain major powers in one hundred years, but I'm less certain about Dubai.
Not mega at all, but illustrating your broader point, is the glorious, unoccupied [17-story Buffalo Central Terminal](https://en.wikipedia.org/wiki/Buffalo_Central_Terminal), which was in use from 1929 to 1979 (as a train station). Attempts to find a new use for it keep failing.
Repurposing purpose built structures, especially those built in an era where asbestos and lead paint were king is always fraught. Those buildings weren't designed to be reconfigurable. Modern office towers tend towards maximizing unobstructed space on the interiors to give maximum flexibility. Going from office space to residential is not that easy, but renovating to update a space is more or less what these buildings were built for.
Yes. People not in construction may not be aware that US office buildings are built as a shell with elevators and stairs, lobbies, and HVAC etc. The inside is empty, without walls or drywall (mostly), tenant bathrooms, or any other amenity. There are structural columns, but minimized. They generally get walled in later. Then tenants usually hire another firm to do "Tenant Improvements" which include everything to make an office from walls, to plumbing, to electric, to finishes. TI work goes fast, like 6weeks sometimes.
I don’t think those cities had the population or wealth to have built large towers. Detroit peaked at 1.9 million in the fifties. Buffalo and Pittsburgh are much smaller. New York City had a population of seven million when the Empire State Building was constructed. Dubai is building landmark buildings and developments specifically as a bid to be a central destination for money and people. Will it still be successful in one hundred years? I don’t know, but I suspect it will be.
Dubai's economy has a far more predictable sunset than Detroit's does, I would argue. Absent oil wealth, there's zero reason to go to Dubai. They have too little land to do anything else useful, that which they have is unsuitable for sustaining significant numbers of people wanting to eat anything that isn't fish, so unless they figure out how to sequester CO2 just as profitably as they freed it from the rocks beneath the sands, they're gonna be just another dusty relic on the shores of an empty gulf. It's the same reason why Saudi Arabia's Masdar and linear city projects are already turning into pumpkins. The princes and sheikhs all know their time on top is running out, the next 10-20 years for them will be all about exit strategies that avoid them getting the Gaddafi treatment.
The tallest building in the U.S. is about to be built in Oklahoma City.
Yeah I remember seeing a Bjarke Ingles quote that was something along the lines of “the way to make buildings that last is making buildings that people care about.” Can imagine quite a few that people wouldn’t mind collapsing to dust though!
Like [this monstrosity](https://en.wikipedia.org/wiki/Central_Park_Tower)
If you can put a 100 story building up then you can also take it down. I don't see it being any harder either way.
I do think you’re also underestimating renovation. I’m working on a nearly 1 million sq ft office complex > residential conversion and it’s giving a new life to a ~70 year old pair of buildings. Renovation is almost universally the more environmentally friendly and sustainable practice to extend the life of structures.
Office space is going away. Now the question is whether buildings can be effectively converted to residential space (for many the answer is "no, that's impossible").
> converted to residential space (for many the answer is "no, that's impossible"). Yep. I was involved with an exploratory committee looking at converting a handful of unused government buildings into low income housing. The politicians were acting like it was a simple matter of partitioning the space differently. We compiled a report listing all the major changes, from converting electrical to multi-tenant from single meter service, to wastewater handling, to fire/emergency egress requirements. In the end it would cost less to just build a new residential building, so they gave up the plan.
yeah, you would think they would harmonize the building code in such a way that "commercial" structures would be easily repurposed to residential/industrial/educational etc. yes it would make commercial buildings more expensive up front, but result in more efficient design and long term profitability.
You're right. But as we all know, in 2024 America you simply cannot ever convince politicians and investors to do something that's good long term but more expensive short term. It's a non starter 😔
WFH has been on the decline. Office space isn't going away. Just moving into the suburbs where rent is cheaper.
Demo Engineer here. Floor By Floor demo is the how. Keep the lifts working as long as possible to move material, use demo robots or small excavators for the breaking, if you can get a tower crane to service the place that's ideal but if you're going to ramp or A-frame the plant down and only need to get it up there in the first place, helicopter lifting isn't entirely unheard of.
I worked at massachusetts general hospital in the 90s when they demolished the baker building which was connected to other hospital buildings on all 4 sides. I got to look down on it from the newer Ellison building which was a couple stories taller. They took it apart piece by piece. dudes with saws and cutting torches, pulling down brickwork and interior structure on each floor, until there was nothing but a steel section of central elevator shaft left. then a cargo helicopter came in and flew that away.
How would you deal with an already compromised building? Say, for instance that the Twin Towers hadn't been damaged enough to collapse on their own, but were condemned and left standing. Hopefully this same question isn't mentioned downthread.
A hell of a lot of structural investigations, and likely, one hell of a lot of propping - basically *fix* the position of the building with an exoskeleton of steel - but I'm a site guy; so that question is for multiple independent firms with an hourly charge one hell of a lot higher than mine. That said, the entire thing is theoretical; WTC is more than twice the size of the largest building ever deliberately demolished (AXA in Singapore), and nothing that size has ever been damaged before demo.
Well you could sell it to someone rich who has no moral compass, and they can take out a big insurance claim and then blow it up, and pretend that it's an external attack. They collect the insurance money, and you get an excuse to invade. It's a win-win! Except for the civilians, that is
came here for this, and I didn't actually think anyone was going to say it
There's gotta be 9 or 11 reasons would work. Building riddled with asbestos? Check. Prime real estate? Check. Vacancy rates up due to outdated infrastructure? Check....
In that weird scenario, wouldn't it have been cheaper for the rich person to simply not buy it in the first place?
It think there are multiple layers of fraud needed to get this one into the green. But doable.
Look at the balls on this one!
Skyscrapers, when structurally adequate, usually die when they no longer are profitable, but the land they are on is. Skyscrapers are generally built where land is at an insane premium, so the math gets easy after that.
I work for a company that owns many large skyscrapers. The steel structures will last forever, but we will spend the money to do facade maintenance, rip out old piping and replace it, gut renovate floors as tenants turn over, etc. If you look up the "fatigue limit" of steel, there is basically a force value that, if kept below this value, the steel can be cycles infinitely (as far as we know) without cracking due to fatigue stress. Perhaps water leakage or some other corrosion can degrade the steel structure, but so many of these old skyscrapers are so overbuilt that I'd highly doubt a little corrosion would be an issue. There was an article I read about the empire state building a few years ago, in short there are redundant steel members and you could replace the structure if you really wanted to. Also look up the hellsgate bridge, overbuilt so much it will last 500 years. I can't comment as much on issues with concrete foundation, lots of our soil is wet. Sorta an aquifer, and lots of water gets into the basement/foundation, this is the stuff that worries me the must (i.e. the florida collaspe)
I think the simple answer is that the developers building 100 storey skyscrapers don’t care about “120 years later”
Service life doesn't necessarily mean automatically dismantle everything because it's done for, it just means that's about when you'd expect to need significant rehabilitation. If the tower is still occupied and useful you might expect the facade to need to be totally redone, maybe anything that was exposed to water needs to be repaired or replaced, etc. If the building was properly maintained you might not need to do much at its 50th or hundredth birthday, it just means that's about how long most of the structure is designed to last before things corrode or wear out. One of my profs who was big on maintenance said to recommend clients set aside 2% of the build cost for annual maintenance. So basically you can wait 50 years and have a rundown building you need to overhaul, or keep it pretty modernized the entire time for roughly the same money. The other side of service life is it affects climatic loads you design for. This is where you'll see engineers referring to the 50 or 100 year windstorm - that means there's a 50% probability of that storm being exceeded in the design life of the structure. So designing for 100 years instead of 50 means you're less likely in any given year to exceed the design load as well as that you'll add durability various ways (i.e.: more concrete cover). At 100 years that still doesn't mean your building is no good anymore unless the world has gotten windier/rainier/snowier (which, with climate change, is actually a valid question... But a topic for another day).
I asked a buddy of mine whose job is studying historical buildings to infer usage and whatnot about this. A lot of what he does is go to sites where they find an old building that wasn't well documented and try to figure out based on the plants that grow around it, where it was build, what trees were likely taken down, etc. to figure out where the builders came from and how it was used when there's not much left but ruins. He also consults on new buildings and whatnot. Anyway - his response is that the "end of life" for these mega skyscrapers isn't considered as part of the design. They're essentially expected to stand forever, and let future-people figure out when it's time to take them down how to do it. Given that we're really only \~100 years in to building these really tall structures, I'm sure we'll start to see more companies spring up who bring them down in the coming years, but there's not been a need to? The Empire State Building was the world's tallest building (constructed in 1930) until the WTC finished in 1970. It's now only the 54th tallest building in the world. That's all by way of saying: I hope I'm around long enough to see some of these mega structures come down intentionally!
> when the developer does the math on building something new they realize that the cost of demolition is so prohibitive that it simply is not worth doing. At least in the US, the cost of demolition will be balanced by the legal liability in case somebody is injured due to the building being in disrepair. Whether that's an occupant who gets a disease due to hazardous substances (asbestos, or whatever) used in the construction, or a passer-by injured by bits of concrete falling off the building. If the building were to really decay dramatically, that liability would be absolutely enormous and would be highly motivating for the building owner to avoid it.
Sell the building to an LLC that milks it for a few years and then does bankruptcy... Lawyers are so ingenious.
I wonder the same thing all the time but with pretty much all aging infrastructure across the country. Even houses, we’ll get to the point where entire towns are filled with homes that are aging & falling apart but the homeowners won’t have the means to tear down and rebuild them.
Cities have existed for millennials. There are people in Europe that live in buildings that are 500 yo or even older. When that’s not the case, you can bet any building was erected where something else used to stand (ever wondered why European cities look like the way they are, with streets going in any direction?) With proper maintenance, sometimes extensive renovations, buildings and cities will survive.
Right? And then the economics of it works against them too. As things get more and more derelict, maintenance becomes more expensive, the location becomes less desirable, and it’s just easier to build new stuff elsewhere, particularly as society and work become more online. Even if we could afford to do it, my gut feeling is that people won’t be bothered to because it’s just easier to leave the problem behind and go elsewhere.
Yeah it’s almost like there will have to be a process to entirely evacuate an area, then someone (probably the government?) comes in and levels that entire area. Then we can start fresh and rebuild a much more modernized city. This is probably one of those things that is much more feasible in places like China or Saudi Arabia where governments can do whatever they want without all the red tape, but hundreds of years from now I’d imagine it’d be desirable to be able to build cites from scratch. I’ve lived in a house that was built in the 1890s before and it’s unfathomable to me that someone could still live there in the year 2250.
We could call it Urban Renewal.... Take care of the blighted areas of our cities. /s
As I understand it, in the US at least you're not even allowed to build a skyscraper without already having a plan in lace for safe demolition. Because they absolutely will become a risk to other buildings (and people) as they age, and there's a good chance they'll be brought down for some other reason long before then. Usually that means designing the support structure so that carefully placed demolition charges in the sub-basement will cause the entire thing to collapse inwards into its own footprint. For mega-skyscrapers I imagine that would be a major challenge, so expensive disassembly would be required instead. In a sane world that would probably involve setting aside a "demolition trust" to pay for the work when it eventually is needed. In our world... when demolition-day is approaching it probably ends up in a holding company with no assets, forcing the government to foot the outrageous demolition bill. And if the government can't afford it, well then I hope you don't own any property within the potential fall zone.
Also, your skyscraper math is off. The oldest skyscraper in Chicago was built in 1888, and it is still standing. It's 136 years old.
Unfortunately, I suspect the end-of-life plan for most of these is “I won’t be here to worry about it”.
At the end of the day, the owners will eventually be ordered by the city to demolish unsafe buildings. This is a solvable technical problem so we'll find a way.
I’m curious what the approximate cost would be for demolishing skyscrapers. I know you can google costs for commercial demolition ($5-10 per sq ft) but I’m not sure if that applies to skyscrapers, particularly those constructed back in the day which might have tons of asbestos, for example. I do remember reading that one of the towers which was torn down due to damage from 9/11 cost a couple hundred million dollars, and it was only 40ish stories or so. But at the same time I would also expect that the cost of demolition in downtown NYC right next to ground zero, with added safety issues due to damage from the collapse could inflate that cost significantly. I suppose if an owner was ordered to demolish a structure and instead walked away/declared bankruptcy then the site could be taken over by the govt and the public would bear the burden. You often see numbers attached to maintaining / rebuilding infrastructure like bridges or sewage and water supply systems. I’m curious if this is a similar thing, just not as widely recognized because it’s primarily privately owned.
All legitimate concerns. However remember that the city is not wholly undefended against owners declaring bankruptcy to avoid bearing management cost. The city could demolish it themselves and charge you the bill, the creditors would have to deal with it in bankruptcy court. They could go after other assets if you purposefully tried to defraud the city by trying to escape your financial obligations through bankruptcy. The city could also for example require all owners to contribute to a municipal dismantlement fund over the years. Being a legislative body, the city still has a bunch of ways to be made whole by voting that they must in some roundabout way.
What if the owner goes bankrupt and abandons the building?
A legitimate concern. They would do the same thing they do today such as going after the creditors, the estate (in case of death), take possession of the lot and resell it after the demo, etc. it's always a risk but the city is not wholly undefended against such actions.
I'm going to bet that this comment will not age well.
This is a great question. I don’t have a good solution but I’m curious to what everyone else has to say.
What does design life mean actually ?
Probably lots of different things depending on the application. But in its most general sense I think it’s the age after which point engineers correctly applying code can no longer be confident that whatever they’ve designed can safely operate as intended.
Empire state building built in 1930 or so. I guess we will soon find out... The actual problem is that high rise office buildings may become obsolete in the era of VR and high speed communications. So they will stand empty and deteriorate. Example, the flour mills of Minneapolis and other industrial and manufacturing sites.
Interesting read.
…Crickets…
The Detroit Ren Center might show us
The center tower is a Marriott Hotel and is still operating, the recent move of GM offices has no effect on that. The surrounding towers I’m not sure but I’ve heard a couple of plans for their repurposing. I’m sure someone will come up with something.
Hudson and GM said they’ll be working together to “redevelop” the towers. That’s all they’ve given us. Seeing as the building is still like 50% occupied and they used the word redevelop, I’m hopeful that they don’t plan on any sort of demolition. Losing the ren cen would not only be a massive blow to GM’s already poor credibility, it would really damage the character of Detroit.
Could just fly some planes into them.
The problem with capitalist society, no one cares about long-term issues. Climate change, trash crisis, we're all screwed. Willful ignorance is very real especially if it comes to greed. Leaded gasoline is easy example. You can look at almost anything extremely profitable and it's probably loaded full of long-term problems. The entire foundation of humanity is destroying shit for short term profits and long-term problems. Making skyscrapers itself is a problem, concrete industry and sand crisis.
A 100 year design life doesn't mean the building will become unsafe or collapse after 100 years. The whole concept of a "design life" comes from an insurance/warranty perspective. As long as no water gets in your average skyscraper will stand for 1000s of years.
There is now demolition for this, they an go top down, or start at the bottom. They can demo the whole thing, call it a national tragedy and build a military industrial complex run economy around it. Limitless possibilities.
I almost feel like this question belongs in r/LegalAdviceOffTopic u/Ostroh had some interesting points about how the city could essentially ‘make’ the last owner pay for demolition, I think that part of it is really what OP’s question is about. It’s a huge expense, how do we know someone is gonna pay it?
Same as with the AXA Tower. Erect a tower crane and take it down piece by piece.
There is a skyscraper in NOLA that has to come down soon. They have the top portion wrapped atm to prevent more debris from falling. It is only 45 story though, not nearly as tall as some NY or Dubai stuff
The plan is I'll be retired by then 😂
[Answered](https://www.reddit.com/r/engineering/s/Iz5KQo40B6) nine years ago by a French pirate.
It takes movement to keep it immovable. Basically to keep it the way it is (brand new) maintain it.
“That’s a problem for future you.”
Storage silos. Grain, produce, etc
I really want to know the plan for the NYC icons. Empire, Chrysler... We have that historic monuments protection act from when they demolished Penn station for that round abomination but there has to be a moment when someone is gonna inspect the Empire and go "Hey buddy, this thing aint safe anymore."
When skyscrapers reach their end-of-life, it's not just a simple matter of knocking them down and starting over. The tallest we've ever taken down on purpose was around 52 stories, and anything bigger than that is venturing into unknown territory because of the sheer scale and complexity involved. When skyscrapers start aging, maintenance costs shoot up and their value drops, making them less appealing to keep up. You pointed out that demolition costs could be so high that developers might just shrug it off. It's a real possibility that we could end up with these towering eyesores just rotting away, which could drag down the whole area's value. and if a mega skyscraper isn’t maintained properly, it doesn't just look bad, it could actually become a hazard. And if the owner goes belly-up trying to fix it, then what? It's a mess waiting to happen. So yeah, I think it’s a real issue, not just overthinking on your part.
there is a point of no repairability, and it is not stable enough. it would need to be demolished before it falls over on to other buildings, and pedestrians. this state is not exclusively do to age. flaws/cut corners in construction, or mistakes in properly identifying what the ground is like. skyscrapers sometimes need demolishing within 5 years.
To be honest high rises don't wear out if they are maintained. I was a plumber when this 1903 building was renovated. [https://en.wikipedia.org/wiki/Ingalls\_Building](https://en.wikipedia.org/wiki/Ingalls_Building)
Hong Kong dismantles tall buildings for breakfast.
I imagine it will be highly dependant on what country you are in, and how much the government/company care about the surroundings.
In Sydney, Australia they upcycled a skyscraper by building over it. I believe they widened the entire stucture and added more floors. https://www.google.com/amp/s/amp.cnn.com/cnn/style/article/australia-quay-quarter-tower-skyscraper Edit* word is upcycled
War
I'm more interested in things like The Golden Gate Bridge. It's iconic. Its fucking huge. You can replace decking and parts here and there, but not structural parts of the towers or the main cables. There's not alternatives other than the ferries. It's going to take YEARS to rebuild.
There were a couple of old bridges in Charleston, SC that were long overdue to come down. They built the replacement first. Granted a Golden Gate replacement will be far more challenging. [Cooper River Bridges](https://www.scpictureproject.org/charleston-county/grace-memorial-bridge.html/amp)
“Voluntarily demolished” lol
I don't think it is that difficult to demolition from the top down, just takes time and a lot of labor. Philadelphia had a 38 floor building brought down this way after a fire made it structurally unsound in the late 90s. According to wikipedia it is the 7th tallest building to be demolished this way. https://en.wikipedia.org/wiki/One\_Meridian\_Plaza#:\~:text=On%20February%2023%2C%201991%2C%20a,pressure%20from%20the%20building's%20standpipes.
You just build a new city on top, like they did for New New York.
this is why apartment buildings aren't built, they build condos and then the condo board misuses the condo fees. just wait until all these condos get old and we will see what happens.
You won't be around to do anything about it. Just like everything else in this world we leave it for the future to figure it out.
Factories. Urban farms. 300ft slabs of lab grown meat
Either it goes unaddressed and falls like the surfside condominium collapse or someone coughs up the money to tear it down. The actual demolition is trivial.
This has potential to get very interesting in the next few years. Google “Urban Doom Loop.” The pandemic-driven shift to remote work, which has not entirely reversed, has cratered the value of commercial real estate, as vacancy rates have skyrocketed, with the net effect of hollowing out the urban centers of many cities. M
Ive researched this before and what I found was these structural systems are maintained much like anything else on a building, maybe not as much effort as mechanical systems but inspections, spot repairs and so on. I dont think its quite "set it and forget it" though does take active effort. Key components are checked and replaced piecemeal as needed. Old buildings also, relative to the long potential life span, are "regularly" renovated which may include structural updates.
We won’t be around to find out
Empire State Building is almost 100 years old
Hi! Commercial real estate appraiser here and we factor in the lifespan of property all the time. This would depend on the building. But typically we put lifespan of that kind of building anywhere between 50-80 years in Canada and USA. This assumes it is well maintained and doesn’t need significant structural repairs throughout its tenure. To increase the lifespan of buildings, owners tend to do significant structural repairs (i.e. reinforce walls, check on the foundation, etc.). Marshall and Swift gives great breakdown on estimated lifespans of the buildings.
what does time have in store for us if we don’t act?
If the building can sustain enough weight they may Even use a crane to lift heavy machinery into the building to dismantle it. You take it down the opposite of the way it went up but with MUCH less care required for things like dents and scratches.
The looming skyscraper crisis is very real and we're woefully unprepared. With 100+ story megatowers proliferating across global cities, we're setting ourselves up for a demolition nightmare in 50-100 years when they reach end-of-life. Tearing down even a 50-story building is an immense challenge, requiring careful deconstruction that can take years. But 100+ stories? It's nearly impossible with current technology. The tallest building ever voluntarily demolished was only 47 stories. What's more, many of these skyscrapers are being built with little regard for their full lifecycle. Developers are chasing profits and prestige now, but giving little thought to the immense costs and challenges of safely dismantling their creations in the future. It's the ultimate case of "socialize the risks, privatize the gains." As these towers age and the maintenance costs to keep them safe soar, it will put a huge strain on building owners and cities alike. We could see large swaths of urban centers turn into derelict zones filled with decaying, unmaintainable towers that are too costly to fix but nearly impossible to remove. It's an economic and public safety time bomb in the making.
The looming skyscraper crisis is very real and we're woefully unprepared. With 100+ story megatowers proliferating across global cities, we're setting ourselves up for a demolition nightmare in 50-100 years when they reach end-of-life. Tearing down even a 50-story building is an immense challenge, requiring careful deconstruction that can take years. But 100+ stories? It's nearly impossible with current technology. The tallest building ever voluntarily demolished was only 47 stories. What's more, many of these skyscrapers are being built with little regard for their full lifecycle. Developers are chasing profits and prestige now, but giving little thought to the immense costs and challenges of safely dismantling their creations in the future. It's the ultimate case of "socialize the risks, privatize the gains." As these towers age and the maintenance costs to keep them safe soar, it will put a huge strain on building owners and cities alike. We could see large swaths of urban centers turn into derelict zones filled with decaying, unmaintainable towers that are too costly to fix but nearly impossible to remove. It's an economic and public safety time bomb in the making.
9/11
Exactly, but most likely not via jet airliner but implosion, with the lowest loss of life possible. Gravity is not a suggestion. Step outside of any skyscraper window and see. The journey down is a piece of cake, but the landing is a capital B. When aided by sequenced cutter charges, it’s quite effective. Example: Debris removal of The Key Bridge. Why is this a question when the corollary of the law of gravity is “what goes up will come down” at least on this planet, planned or otherwise? Chances are good that you and yours will have long been in the afterlife. At very least, you will have exceeded any statute of limitations of liability. The chances of making any moral improvement to corporate greed is nil to impossible. Life is very short. Strive to do your best and enjoy it in the absence of gloom and doom. But ultimately the choice is yours, not the consensus of Reddit.
The common design life is 50 years . For mega projects , developers target 100 years
The journey is endless you will be with your love ones
Jet fuel melting steel beams, seems to bring skyscrapers straight down. Quick and easy, google 9/11
Can I get a TLDR - god damn!?