i was wondering... roughly, for how many years are skyscrapers supposed to stand?

after what age does it's structure begin to exhibit serious signs of stress requiring it to be demolished?

given that glass is an amorphous solid, it will inevitably morph (studies show that a piece of glass' own weight will cause it to morph - becoming fatter at the bottom). how will this affect skyscrapers where the facade actually holds the structure together (e.g. 30 st mary axe/swiss re)? does this mean that a building like 30SMA will have a much shorter life than concrete-cored buildings further supported by concrete (e.g. eureka tower)?

what are (approximate) life expectancies of supertalls like the WTC (if 9/11 didnt happen), sears tower, and burj dubai when built?

Assuming the Empire State Building is still intact (built 1936), it could be well over 100-150 years.

That's a pretty interesting question, one that I've been wondering myself.

When the life of a super-tall structure, like the Sears Tower for example, does come to an end though it'll be interesting to see how they're going to try to demolish it without having it fall over onto the other buildings...or maybe they'll just take it apart piece by piece..?

The thing I've wondered is about Chinese skyscrapers. Do they use imported steel for them, because I've heard that Chinese steel is only good for about twenty years or so.

It depends on many factors including the materials, location, climate/environment, and overall structural and engineering techniques used, but I would expect an 'average' skyscraper to survive at least a few hundred years.

I hope we never ever see a skyscraper like the ESB, Sears Tower, or any of them have to be demolished because of age in our lifetimes.

They'd have to do it slowly too I guess, piece by piece.

I think wjfox2002 is right, it depends on alot of factors that he's listed.

Assuming the Empire State Building is still intact (built 1936), it could be well over 100-150 years.

I wouldnt compare the Empire State Building with nowadays skyscrapers because its structure is much heavier than those of todays.

Actually the life of the skyscraper is subordinated to the costs of the maintenance of the structure. When the costs and the technological efforts are higher than the building revenues the building is usually demolished. For example the first iron beam building (mainly industrial revolution factories) are very expencive to maintain. They need a (quite expencive) Fireproof coat to allow them to resist fire for a bit longer (allowing the building to evaquate). Reinforced concrete structures are more fireproof since the concrete protects the steel inside. but if the concrete cracs and expecially if water or humidity can enter in contact with the steel the performance of the concrete beam drastically decrease. Concrete servicing is by far more expencive but it surely lasts longer. In the skyscrapers constant monitoring helps saving more money in maintenance.
Answering to the main question let's say that Golden Gate bridge and Empire state building will be already collapsed without any maintenance.

I can't see why a skyscraper couldn't last hundreds of years. Except maybe if the foundation had alot of water damage.

Entire floors in all skyscrapers are gutted for tenant renovations. I would imagine that this would provide a good opportunity for any major structural or mechanical renovations.

I do wonder about buildings that have an all glass facade. Would a glass facade stand up over time?

thats what i was wondering about glass facades... cos it's amorphous, it'll deform over a sufficient period of time.

now this is not really a problem for buildings where glass is simply a facade (i.e. nearly all new buildings 7wtc, eureka, 2ifc, trump tower etc) as it can simply be replaced panel-for-panel.

but what about buildings where glass actually supports the structure (only example i can think of is 30 st marys axe/swiss re)? how would you go about replacing the glass structure in a few decades time?

well, if old cathedrals around europe are several centuries old, modern skyscrapers should last as long or even longer given that they are far more technologically advanced. if the ESB is maintained properly, i don't see why it can't last a few centuries.

all-glass facades should be easy to replace overtime; gradually replace panels as they warp...

the 1136' aon center in chicago had an entirely new facade put on and that building was only built in '73/'74

Those in Yemen are over a thousand years old, made of mud bricks and stone, are still standing.

Those in Yemen are over a thousand years old, made of mud bricks and stone, are still standing.

But are made from natural resources.

Modern skyscrapers are a production of the industrial revolution which dates back to the 19th century at the very earliest.

We have no idea how they are going to last.

thats what i was wondering about glass facades... cos it's amorphous, it'll deform over a sufficient period of time.

Sure replacing the panels is not a huge issues in down often in smaller structures

stone also deforms over time, its called erosion. the pyramids are a classic example of this. that said, where i live we have houses of over 1000 years old, the local church is approaching its 1200th birthday. old buildings often dont have a very good shelf life because of things like poor foundations, they need a massive amount of work to keep them up and running, just check out the leaning tower of piza to see what i mean.
as for glass, glass tends to last. i just did some work on stained glass windows which were done in 1357, this is the first time they have ever been restored. had they been cleaned properly theyd not need this work even.

oh, and i remember reading (i dont know if this is true) that heron quays in canary wharf has been designed for a shelf life of 30 years. portcullis house in london opposite parliament has been designed to last a minimum of 300 years. the actual shelf life of a building isnt dependent on that though, if it was the effiel tower would not be standing.

Most skyscrapers have an overhaul every 30 years or so. The facade is cleaned, the structure is checked, repairs and additions are made. The John Hancock center just went through its first overhaul. As long as people inhabit supertalls, they won't be torn down. Most of their structures are kept in air conditioned, relatively low humidity enviroments that reduce corrosion. Any real aging is experienced only by the facade. which if need be can be torn out and replaced.

Also, skyscrapes are rudundant, modular strutures that even if a beam was in a really bad condition (i.e. rusting apart) it could be taken out and replaced with a new one. Doing this would be fairly expensive, but compared to trying to tear the tower down, its a bargain.

So I really don't see a "life expectancy" for skyscrapers. I would imagine, if it was still being mantainted, the Hancock Center could easily be standing 1,000 years from now.

thats what i was wondering about glass facades... cos it's amorphous, it'll deform over a sufficient period of time.

now this is not really a problem for buildings where glass is simply a facade (i.e. nearly all new buildings 7wtc, eureka, 2ifc, trump tower etc) as it can simply be replaced panel-for-panel.

but what about buildings where glass actually supports the structure (only example i can think of is 30 st marys axe/swiss re)? how would you go about replacing the glass structure in a few decades time?
Did you really think the glass itself supports (some of) the building?

Of course not. The facade itself (meaning the steel and/or concrete in it) might support the building, but not the glass.
Glass is far too breakable and weak for that. It could only support a part of the weight, and you could get the building down by just breaking all the panels with a baseball bat.

Contrary to poular belief glass flows at a rate so slow that it takes hundreds of thousands of years for a sheet of glass to begin to lose its shape to the naked eye.

Shortly, i think scyscrapers are designed to last during the economic lifetime of the building, and then some more. Designing a scyscraper to stand for 400 years is a waste of time and money, because its almost never going to happen.

This is an interesting question. But please... if you don't know what you are talking about, don't try to pass it off as fact... Not speaking to anyone inparticular.

ArchITA and ie Turbo explanations sound most logical though.

Most skyscrapers have an overhaul every 30 years or so. The facade is cleaned, the structure is checked, repairs and additions are made. Any real aging is experienced only by the facade. which if need be can be torn out and replaced.


Thats precisely whats happening here in Singapore.

The High Street Centre which is a little over 30 years is undergoing a dramatic makeover. The old facade is torn off and its getting a new glassy one. Theyre even going as far as to change the design of the top :)

Before
http://picas.nhb.gov.sg/data/tn_pcd/19980002919-8262-3202-1096/img0110.jpg

Now - undergoing transformation
http://img51.exs.cx/img51/7618/hs3110.jpg

^ ^ Yep, same is happening in my city too.

There are three points of a building that are of concern. The facade, the foundation and the structual elements.

*Foundation:
Since everything sits on it, it must be in good shape for the building to have a long lifespan. This factor is ultimately at the mersy of the geological effects of the area its built on. If the site is stable, the materials that were used were of good quality and the design was done well, the foundation may have a very very long lifespan. Many ancient structures have proven that a well designed structure can continue to work for centuries.

*Structual Elements:
These are the support beams, girders or anything that supports the structure that ties into the foundation. Because of the motion of the building, metal can and will be fatigued over time no matter the specs that the building is built too. Same goes for concrete as shearing or twisting motion can crack the concrete. There is also geolocialy caused motions such as earthquakes that may not destroy buildings but certainly limit their lifespan.

Ultimately, structual elements are usually made up of two types of materials that are done to different qualities. These elements are metal (mostly steel and iron alloys) and concrete. Often both are used in the same element for the reason that steel is better under tension than compression where it is much weaker. Concrete is the exact opposite, it is weak in tension but strong in compression.

What ever the motion that causes structual failure, it usually happens in the end because concrete is put in tension, metal is put in compression, or a combination of both.

*Facade:
It was mentioned earlier in this thread that the Aon Center in Chicago(one of my fav buildings) had its facade replaced. I know in Toronto, the tallest building First Canadian Place has a similar facade of white mable. I know that FCP has had a hard time with its facade panels comming off back in the 70's due to high wind conditions. This was as a result of an under designed facening system used to keep the panels where they are suposed to be.

So the question with facades is "what does it have to do with the rest of the structure". The answer is that the facade keeps the effects of weathering away from the structure and foundation and if it fails, things in rain and the air can prematurely age the structure and foundation. The facade is a buildings first line of defence from the elements!

The good news here is that most buildings built with removable facades can have them overhauled making there lifespan irrelevent as all it needs is for the rest of the building to remain standing.

As for older buildings where the facade is part of an outer load bearing wall, most are built with hard stone like granite and limestone that are very hard and resistant to weathering and thus should last as long as, well a mountain provided that gaps between joints are kept water tight.







Hope thats informative!

In Montreal (Canada), some skyscrapers are 40 years old and look almost new.
They should last forever...

Is it true that the first Skyscraper ever built is the Chrysler building in NY?
Could it be a building (I dont remember the name) in Chicago?

After so much money is poured into the construction of a skyscraper they still need to spend a lot on maintenance. I doubt they are so fragile as we think. There is many technology involved. Norman Foster's new tower in NYC is adding a 40-storey building on top of a very antique structure. That probably consumed thousands of dollars in technology so that all of the 1920's construction would stand the weight and not collapse.

I can't imagine the Eiffel Tower needing to be shut down because of iron problems. I think it will last forever, unless a bomb falls over it.

Is it true that the first Skyscraper ever built is the Chrysler building in NY?
Could it be a building (I dont remember the name) in Chicago?
depends on what you call a skyscraper.
If it's a structure over 319m tall, then yes.
But that would leave such buildings such as the Woolworth building a lowrise ;)
and leave Europe with only one skyscraper, in Frankfurt :D
But the second guess is right, it's a building in Chicago, thouhg I do not remember it's name either

I think you may mean the Home Insurance Building - built 1881 and demolished 50 years later. It was the first building ever to be supported by a metal skeleton of vertical columns and horizontal beams and was 10 stories and 55 m high.

Well, look at the world in 100 years into the future, buildings that we now consider new and awesome like Swiss RE, will be pulled down and a newer and more superior skyscraper will be built, it's just evolution.

if they pull down a skyscraper (like Taipei 101) how do they do it? do they blow it up? :D

The simple explanation for the lifespan of a modern skyscraper can be summarised thus: If the building is designed only for a functional use (like a residential tower), then it doesn't last more that 4 to 5 decades. OTOH, if buildings are designed for more prestige issues than mere functionality, they tend to be built to last for atleast a couple of centuries. We all know, that Chrysler building and Empire State building, were more products of envy and pride rather than mundane functionality. It's not surprising that they are still standing, and would continue to do for several future generations. And yet within the NY CBD, there are examples of skyscrapers built in the 50's, which have already been brought down. So, I guess the lifespan of a skyscraper is basically an input-output quotient. The more you put into it, the more you would like to keep it standing. ;)