karma-dharma 8

As a student in London in the 1980s, I lived in a succession of buildings built in the late 19th Century with a design life of 100 years (without anticipating the maintenance neglect consequent upon two periods of total war). I drove past one of them last summer and was mildly surprised (no, considering the state we'd left it in, jaw-droppingly astonished) to see it still there.

It's simply not the end when everything begins to fail. Old buildings (and their infrastructure) will stagger on for decades provided their owners think there's value in maintaining them or if there's a ready enough supply of tenants willing to swap a lot of dilapidation for an almost-affordable rent. Buildings between those extremes get knocked down earlier. It's the breadth of this spectrum that spreads the burden of renewing old housing stock and which cushions the shock.

The Palace of Versailles was built in 1623, mostly, and is both standing and operating, as a museum, with way more people roaming around than even at the height of its prominence. So, that's 400 years, this year, but admittedly in a tectonically stable part of the world with relatively benign weather.

But, the issue isn't really an issue; not all of the infrastructure collapses at the same time, and we either find the money to rebuild, or we abandon and move elsewhere. It's not like we're living cheek to jowl EVERYWHERE; there's still plenty of space in the world. Additionally, most buildings will continue to survive, so long as there aren't natural disasters like earthquakes or tsunamis, etc. Roads are a different matter, since there's tons of wear and tear, and we've deferred the repairs on lots of roads, so we might need to do like Schwarzenegger and repair our local streets ourselves.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list

@a-rai, thats a very un-engineer like question. Of course things fails and run out of use full life span - but then its repaired or replaced! Forthunately not everything fails at the same time - and somethimes politicians even put money aside for this ;-) Why should repairs or replacement be impossible? That makes no sense.

--- Best regards, Morten Andersen

The Palace of Versailles doesn't have the metro under it.

A product recall exemplifies systemic failure within a time frame. Large-scale urban projects are typically built in one go. Carbon copy bridges of yesteryear will show signs of distress simultaneously.

How many parts of structures and infrastructure are inaccessible? The materials are left to their nature and struggle with time.

MortenA, which one?

a-rai said:

Carbon copy bridges of yesteryear will show signs of distress simultaneously.

Click to expand...

Not so much. Just because the design is the same doesn't mean a) they were built exactly the same b) maintained exactly the same or c) exposed to the same things.

Differences in loading will create differences in wear, different environmental factors (even micro-climate factors like how much sun hits the deck) will change the stresses and damage caused. A bridge of identical design in New Jersey and Georgia will probably not last as long in New Jersey if the maintenance is the same due to heavier use of de-icing salts. Two bridges in New Jersey a mile apart - one near a manufacturing plant and one serving a primarily residential area. The manufacturing plant will have significantly more truck traffic and greater wear. Two bridges a quarter mile apart with similar traffic but with a city border between them - one city invests in maintaining a bridge and the other doesn't. One will fail earlier than the other.

We had a huge building boom and, in many cases, a large period of neglect. That's absolutely true. And it's true that a lot of it will age into obsolescence in a shorter period than is comfortable. But your use of hyperbole does nothing to engage intelligent discussion on the topic. Post-apocalyptic films of the past? Really? The level of apathy required to end up there is a bit hard to imagine, even if many governments are increasingly unable to function properly.

phamENG, I'm not interested in discussion. I'd simply like to know what you all think about this. There seems to be divergence of opinion already. IRstuff thinks the issue isn't an issue whereas you acknowledge it as such. It would be great if others chime in to understand what the engineering community leans toward. Perhaps then the replacement of the sewage system of an urban agglomeration, for example, could be discussed.

Your premise is completely wrong.

a-rai said:

I'm not interested in discussion. I'd simply like to know what you all think about this.

Click to expand...

Umm...what?

a-rai,

Buildings last a very long time when they are useful and people care for them.

Ancient Rome's problem is that they lost control of their empire, their military, and north Africa where all their food came from. The population dropped and they stopped caring for their buildings and infrastructure. Medieval Bagdhad's problem is that Hulagu Khan captured the place and killed everyone.

--
JHG

I don't think the problem is whether we can maintain individual bridges, buildings, etc. It's how we will pay for maintaining all of them.

One big area of concern is the amount of civil infrastructure - streets, water, sanitary sewer and stormwater pipes, treatment plants, fire and police stations, schools, and so on - needed to support suburban lifestyles. Compare the revenue they generate to the maintenance costs. I strongly suspect the ratio will be less than one. How much longer will this be sustainable? Will we have to triage neighborhoods? If so, how?



This chart represents the change in infrastructure per capita in Lafayette, Louisiana before and after suburbanization. Yes, now we have more durable materials than clay pipe and tar-macadam, but it still shows an increased burden in infrastructure costs per household.





My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

act... I didn't realise there was that huge escalation... likely representative of everywhere. thanks...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

Our cities are a big bang of construction. A few Chinese built 57 stories in 19 days. Ask yourself what China builds in 365. According to the Council on Tall Buildings and Urban Habitat, 14 cities now have more than 100 buildings at least 150 m (492 ft) tall. Nobody maintains the foundation of a skyscraper. Consequently, what goes up must come down. Earthquakes aside, time is a disaster in the making. It will trigger a domino effect.

Where's a Billy goat when you need one?

Nobody maintains the foundation of a skyscraper.

Click to expand...

What maintenance are you referring to? There are lots of buildings in excess of 200 years old that probably haven't anyone maintain their foundations.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list

Most modern architecture will be functionally obsolete in 200 years.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

"Consider the amount of structures and infrastructure (electrical and plumbing systems, etc.) built in a relatively short period of time. What will happen when everything starts to fail?"

We are already at the point where perfectly good buildings are destroyed because it is economically 'better' to build something different.

The failure of infrastructure is going full speed, bridges are falling down due to no maintenance, for example.

I think what will happen is that the infrastructure will need replacing and will consume a higher and higher portion of budgets, but everyone will simply carry on as if this is fine.

I must be missing something as a history and architecture buff bc stateside our cities look nothing like they did a century ago. Popular landmarks have survived but most everything else is replaced after a half-century or so.

CWB1, 13 years ago CBRE (the world's largest commercial real estate services and investment firm) had this to say about Manhattan: the average larger midtown commercial building is 57 years old; the average midtown south one is 92; and downtown it's 63. This is based on buildings measuring over 75,000 square feet in midtown south and downtown, and over 150,000 square feet in midtown. The majority of these buildings - 55.1% in midtown, 93.7% in midtown south and 55.5% in downtown - are over 50. The Bloomberg administration's PlaNYC stated the following: by 2030, almost 70% of the power plants that supply the city will be more than 50 years old.

More recently, New York City's strategic plan has this: much of the city's infrastructure was built a century ago and has suffered from historic disinvestment, neglect, and poor maintenance. On average, our sewer mains are 85 years old, water mains are 70 years old, and the electric grid dates back to the 1920s.

Here is a picture of New York City in 1928. Notice the Woolworth Building. It was the tallest building in the world in the 1920s. The Chrysler Building was completed 2 years after this photo was taken, and the Empire State Building became the tallest structure of any kind 1 year after that.