Cost to build Gerard K. O'Neill's "Island Three"

On Fri, 01 Oct 2010 12:49:35 -0400, Greg D. Moore \(Strider\) wrote:

Derek Lyons wrote:
"John F. Eldredge" wrote:

I find the Pantheon in Rome particularly impressive. It has an
unreinforced concrete dome that has survived 2,000 years in an
earthquake zone. A lot of current-day concrete structures start
crumbling within a decade after being built.

And a lot more don't.


And of course we no longer have examples of all the Roman architecture
that didn't survive because it was poorly built.

It's a self-selecting observation. Like folks in Florida who talk about
homes not destroyed by hurricanes. "They don't build them like they used
to!" Yeah but you're only the seeing the ones that survived, not all
the ones that had previously been wiped out.
D.

I realize that fact; still, surviving 2000 years of earthquakes is an
impressive result.

--
John F. Eldredge --
"Reserve your right to think, for even to think wrongly
is better than not to think at all." -- Hypatia of Alexandria

On Sat, 02 Oct 2010 09:25:38 +0100, Peter Fairbrother wrote:

Carey wrote:
Greg D. Moore (Strider) wrote:
wrote:
On Oct 1, 9:49 am, "Greg D. Moore \(Strider\)"
wrote:
...
But are you suggesting that the world's largest unreinforced concrete
dome, and the world's largest dome of any kind before 1881, is still
standing because it got lucky? That they could build it at all is an
engineering marvel.

There's no doubt it's an engineering marvel. But also keep in mind
they were building on previous experience, but successful and not so
successful.

So that's like - everybody, everywhere, at all times, throughout all of
history, right? Is there any time in engineering history when this
generalization isn't true?

(I have several books on the role of failure in engineering history
collectively showing its ubiquity, by the way, so this really is just a
rhetorical question.)

And there's a lot of stuff they "over-built" since they didn't know
any better.

So you are saying they used sufficient margins of safety to account for
the uncertainties in their designs and materials? Egads, what
outrageous deviation from engineering practice!

Is the stuff that didn't fall down in 2000 years of seismic history
actually "over-built" while the stuff that collapsed "properly built"?

Are we saying then that the Pantheon is standing because "they didn't
know any better"?

Parthenon?

Pantheon. The Pantheon is a temple in Rome, and still intact; the
Parthenon is a temple in Athens, and only the colonnade is still standing.

--
John F. Eldredge --
"Reserve your right to think, for even to think wrongly
is better than not to think at all." -- Hypatia of Alexandria

On Oct 2, 7:05*am, "Greg D. Moore \(Strider\)"
wrote:
Carey wrote:

Is the stuff that didn't fall down in 2000 years of seismic history
actually "over-built" while the stuff that collapsed "properly built"?

Yes.

That depends.

If a building is built so that it will last 100 years, and that land
is going to be re-used for another building in less than 50 years,
that certainly sounds reasonable.

However, a building that is built to last 100 years is presumably
somewhat more likely than a building built to last 2,000 years to
experience a catastrophic failure in 10 years - while still in use.

If we consider the cost of a building failure which results in one
fatality to not be _in the slightest_ an externality, but instead to
equal the cost of the medical care required to restore the fatality to
life and health - well, since that cost will include a potentially
unlimited amount of money spent on scientific research (nobody has yet
resuscitated someone pounded to jelly by a ceiling falling on him)...
spending the extra money to build buildings with an MTBF of 2,000
years is likely to be worth it.

A building that costs ten times as much to build is cheaper than an
*infinite* amount of liability.

Thus, in a society with a sufficiently high intolerance for imposed
risks, building standards can be very strict.

John Savard

In article
,
Quadibloc wrote:

On Oct 2, 7:05*am, "Greg D. Moore \(Strider\)"
wrote:
Carey wrote:

Is the stuff that didn't fall down in 2000 years of seismic history
actually "over-built" while the stuff that collapsed "properly built"?

Yes.

That depends.

If a building is built so that it will last 100 years, and that land
is going to be re-used for another building in less than 50 years,
that certainly sounds reasonable.

However, a building that is built to last 100 years is presumably
somewhat more likely than a building built to last 2,000 years to
experience a catastrophic failure in 10 years - while still in use.

If we consider the cost of a building failure which results in one
fatality to not be _in the slightest_ an externality, but instead to
equal the cost of the medical care required to restore the fatality to
life and health - well, since that cost will include a potentially
unlimited amount of money spent on scientific research (nobody has yet
resuscitated someone pounded to jelly by a ceiling falling on him)...
spending the extra money to build buildings with an MTBF of 2,000
years is likely to be worth it.

A building that costs ten times as much to build is cheaper than an
*infinite* amount of liability.

Thus, in a society with a sufficiently high intolerance for imposed
risks, building standards can be very strict.

I suggest you look up the term "opportunity cost" before spouting this
sort of nonsense again.

Oh right, I guess I forgot to killfile you in this group. In you go.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

"John F. Eldredge" wrote:

On Sat, 02 Oct 2010 09:25:38 +0100, Peter Fairbrother wrote:

Parthenon?

Pantheon. The Pantheon is a temple in Rome, and still intact; the
Parthenon is a temple in Athens, and only the colonnade is still standing.

"On 26 September 1687, an Ottoman Turk ammunition dump inside the
building was ignited by Venetian bombardment. The resulting explosion
severely damaged the Parthenon and its sculptures." (wikipedia)

Nothing like storing bombs in a building then losing it to artillery
fire to make it look like it was poorly built.
--
Tomorrow is today already.
Greg Goss, 1989-01-27

On 10/1/2010 12:17 PM, wrote:


But are you suggesting that the world's largest unreinforced concrete
dome, and the world's largest dome of any kind before 1881, is still
standing because it got lucky? That they could build it at all is an
engineering marvel.

WOW! This is like the grand old days of the Sperry Ball Turret
Evacuation Procedures thread, and the ever-legendary Railway Track
Gauges Through The Ages thread!
And we haven't even begun discussing the giant awnings on the Colosseum
or the Double Quinqueremes yet. :-)

Pat

On 10/1/2010 6:31 PM, Invid Fan wrote:

Was it the only dome they tried to build like that, or did they do a
number of them and it's the only one left?

If you count the Eastern Roman Empire, there's this little item:
http://en.wikipedia.org/wiki/Hagia_Sophia
Nero's Golden House had a pretty impressive dome on it also:
http://www.antinopolis.org/hernestus/ac991416.jpg

Pat

On 10/1/2010 8:01 PM, Greg D. Moore (Strider) wrote:

There's no doubt it's an engineering marvel. But also keep in mind they
were building on previous experience, but successful and not so successful.
And there's a lot of stuff they "over-built" since they didn't know any
better.

Better to overbuild a lot than to underbuild a little.
Beauvais Cathedral comes to mind:
http://en.wikipedia.org/wiki/Beauvais_Cathedral

Pat

On 10/1/2010 9:30 PM, Derek Lyons wrote:

The two statements are unconnected Carey, being an engineering marvel
is no guarantor of being a survivor. The Colliseum was an engineering
marvel, as was the Parthenon. Neither of them are looking too good
nowadays.

Yeah, but the Parthenon was destroyed by a gunpowder explosion in 1687,
not a earthquake.
They couldn't very well plan for that in Attic times. ;-)

Pat

On Sat, 02 Oct 2010 19:14:04 -0600, Greg Goss wrote:

"John F. Eldredge" wrote:

On Sat, 02 Oct 2010 09:25:38 +0100, Peter Fairbrother wrote:

Parthenon?

Pantheon. The Pantheon is a temple in Rome, and still intact; the
Parthenon is a temple in Athens, and only the colonnade is still
standing.

"On 26 September 1687, an Ottoman Turk ammunition dump inside the
building was ignited by Venetian bombardment. The resulting explosion
severely damaged the Parthenon and its sculptures." (wikipedia)

Nothing like storing bombs in a building then losing it to artillery
fire to make it look like it was poorly built.

I didn't make any comments about how well-built the Parthenon was, only
about what its current condition is. It never had a dome, by the way.

--
John F. Eldredge --
"Reserve your right to think, for even to think wrongly
is better than not to think at all." -- Hypatia of Alexandria