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Default Can some building guru explain how the earth can move but cause no structural damage?

After last night's 'quake, which I felt most strongly, I can't
understand how this much shaking results in no discernible damage, not
even new hairline cracks.

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak? So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?

Or is it down to build quality and would older or newer properties be
at greater risk?

MM
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Following up to MM wrote:

Or is it down to build quality and would older or newer properties be
at greater risk?


I'm as far from a guru as it gets but one opinion I can pass on about
really old houses is that when bombs dropped in WW2 they just sort of
lifted up as separate bits and settled back down again in roughly the
same place :-)
--
Mike
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On Wed, 27 Feb 2008 09:11:16 +0000 someone who may be MM
wrote this:-

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak?


That's partly it. If one part of the land on which the house is
built moves one way and the rest of the land moves the other way
then the house will be re-arranged.

So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?


At the low energies of this relatively minor earthquake. At higher
energies more buildings are not able to cope with the shaking.

Not all buildings are the same, but as a generalisation the better
built will stand up better. In an areas prone to large earthquakes
some buildings have now been built with active systems to lessen the
effect of earthquakes, for example some tall buildings in Japan.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54
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Default Can some building guru explain how the earth can move but causeno structural damage?

AIUI it's a combination of local soil conditions & foundations (how
much quake energy is transferred to your building), the natural
resonant frequency of the building compared to the vibrational
frequency of the quake (certain sizes and shapes of buildings are more
vulnerable) and the strength and elasticity of the building's
structural elements and the connections between them (timber good,
unreinforced masonry bad).

As another poster pointed out, this is a very small shake -
insufficient to crack even old mortar on poorly maintained buildings -
apart from a few chimneys that were probably in a state where they
could have been lifted off the building by hand. (And I'm rather glad
I dismantled a chimney in that condition within the last few months).
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Default Can some building guru explain how the earth can move but causeno structural damage?

MM wrote:
After last night's 'quake, which I felt most strongly, I can't
understand how this much shaking results in no discernible damage, not
even new hairline cracks.

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak? So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?

Or is it down to build quality and would older or newer properties be
at greater risk?

MM

You would be surpised at how elastic soil, and even concrete steel and
brick structures can be, let alone timber frames.

I remember watching the MOT over the clay soil here going down about 4"
when a 30 tonner backed in the drive, and then coming back up again
afterwards..



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Default Can some building guru explain how the earth can move but cause no structural damage?

The Natural Philosopher wrote:

You would be surpised at how elastic soil, and even concrete steel and
brick structures can be, let alone timber frames.

A couple of years ago I was watching the demolition of a large
Victorian building (Derby Carriage Works C Shop, for those who
knew it).

The gable ends were brickwork about 500 mm thick and 15 m high,
and the demolition excavator had to work very gingerly to bring
it down piecemeal in the right place. Simply nudging near the
apex caused the entire wall to flex to and fro quite alarmingly.
Perhaps it was largely held in place by gravity.

Chris
--
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On Wed, 27 Feb 2008 11:50:09 +0000, The Natural Philosopher
wrote:

MM wrote:
After last night's 'quake, which I felt most strongly, I can't
understand how this much shaking results in no discernible damage, not
even new hairline cracks.

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak? So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?

Or is it down to build quality and would older or newer properties be
at greater risk?

MM

You would be surpised at how elastic soil, and even concrete steel and
brick structures can be, let alone timber frames.


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.


I remember watching the MOT over the clay soil here going down about 4"
when a 30 tonner backed in the drive, and then coming back up again
afterwards..


MOT?

MM
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Default Can some building guru explain how the earth can move but causeno structural damage?

Chris J Dixon wrote:
The Natural Philosopher wrote:

You would be surpised at how elastic soil, and even concrete steel and
brick structures can be, let alone timber frames.

A couple of years ago I was watching the demolition of a large
Victorian building (Derby Carriage Works C Shop, for those who
knew it).

The gable ends were brickwork about 500 mm thick and 15 m high,
and the demolition excavator had to work very gingerly to bring
it down piecemeal in the right place. Simply nudging near the
apex caused the entire wall to flex to and fro quite alarmingly.
Perhaps it was largely held in place by gravity.


Well if it used lime mortar, it certainly wouldn't have been held
together by that ;-)

Largely I suspect the way blockwork developed, was that early man piled
up stones , then plugged the gaps with sand, then discovered the sand
washed out. But a bit of lime in the sand stopped it washing out.


Which is really all lime mortar is. Sand that doesn't wash away.;-)



Chris

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Default Can some building guru explain how the earth can move but causeno structural damage?

MM wrote:
On Wed, 27 Feb 2008 11:50:09 +0000, The Natural Philosopher
wrote:

MM wrote:
After last night's 'quake, which I felt most strongly, I can't
understand how this much shaking results in no discernible damage, not
even new hairline cracks.

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak? So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?

Or is it down to build quality and would older or newer properties be
at greater risk?

MM

You would be surpised at how elastic soil, and even concrete steel and
brick structures can be, let alone timber frames.


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.

I remember watching the MOT over the clay soil here going down about 4"
when a 30 tonner backed in the drive, and then coming back up again
afterwards..


MOT?


Ministry Of Transport Type I road base material. Essentially crushed
limestone.

MM

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Default Can some building guru explain how the earth can move but cause no structural damage?


"MM" wrote in message
....


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.


Even more solid when it falls on you :-(

Mary





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On 27 Feb, 16:03, "Mary Fisher" wrote:
"MM" wrote in message

...



Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.


Even more solid when it falls on you :-(

Mary



This is why timber houses are preferred in earthquake zones in the
states.
Thing is, if you are also in a tornado/hurricane zone, then your light
timber house entirely blows away.
Simon.
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On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:


"MM" wrote in message
...


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.


Even more solid when it falls on you :-(


Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM
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Default Can some building guru explain how the earth can move but causeno structural damage?

On 27/02/2008 20:54, MM wrote:

Imagine trying to mount, say, a whole village on some kind
of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device.


http://en.wikipedia.org/wiki/Tsar_Bomba
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Default Can some building guru explain how the earth can move but cause no structural damage?

on 27/02/2008, MM supposed :
There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.


The Brum one a few years ago, despite being further away and not as
big, seemed to be much stronger here. That one managed to wake me up
from a very deep sleep and gave me quite a start.

This one managed to wake me, but I was just at the dozing off stage so
I caught the whole thing. A quiet rumble initially which gradually
built up then just stopped.

I suppose the difference might have been the subterrainian rock strata
and the direction it lays in.

Probably my most startled moment from a natural phenomena whilst in a
deep sleep - was several years ago when the church steeple a 100 yds
away was severally damaged by a lightning strike. I actually think I
was so startled I lifted off the bed :-) The pulse from the strike
caused us quite a bit of damage to our electronics.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


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"MM" wrote in message
...


Yes, I can believe that. But having experienced that tremor as the
first in my life,


SNIP

Totally mind-boggling to me, that tremor last night.

Sorry to highjack your post, but am I alone in 'Tremors' being my favourite
all time film?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257





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"MM" wrote in message
...

Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation.


Well, interestingly enough, not necessarily.

If you're trying to shift rock, eg for road building or quarrying, you use
explosive. Put it near the surface and you get a bang and lots of little
bits of rock flying anywhere - but not much volume shifted.
Put it deep, and it looks a lot less spectacular - but shatters rather more
rock, provided you put enough in.

So if you go deep enough, you'll end up with a shock wave, ie earthquake.
See underground nuclear tests - how do you think they're detected? Locally
stuff is pulverised, but futher away it's more like what you want.

But yes, it is an interesting reminder of the scales involved in plate
tectonics - which is significantly larger than what we experienced last
night.

cheers,
clive

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On Thu, 28 Feb 2008 02:26:30 -0000 someone who may be "Clive George"
wrote this:-

If you're trying to shift rock, eg for road building or quarrying, you use
explosive. Put it near the surface and you get a bang and lots of little
bits of rock flying anywhere - but not much volume shifted.
Put it deep, and it looks a lot less spectacular - but shatters rather more
rock, provided you put enough in.


The same was true in Ye Olden Days with depth charges. If it made a
big spout of water then it was likely to have been set off for a
film or photograph. Ones used against submarines made little
disturbance on the surface of the water.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54
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Default Can some building guru explain how the earth can move but causeno structural damage?

The Medway Handyman wrote:
"MM" wrote in message
...

Yes, I can believe that. But having experienced that tremor as the
first in my life,


SNIP

Totally mind-boggling to me, that tremor last night.

Sorry to highjack your post, but am I alone in 'Tremors' being my favourite
all time film?


First earthquake I noticed was the Lleyn Peninsula one back in 1984. The
building I was in (had got in to work very early) was a concrete 1950s
thing in Fleetwood. When trolleys were pushed up and down the corridors
the whole building sounded (and to a very minor extent, felt) like an
earthquake. Funnily enough, the earthquake sounded and felt like a
trolley... but a very big one. :-)

I saw it many years ago knowing absolutely nothing of it beforehand.
Brilliant. (Not so sure I would wish to view it again - case of right
film, right time.)

Damn sight better than Dune. Which should have been sunk in Waterworld.

--
Rod
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"Rod" wrote in message
...
The Medway Handyman wrote:
"MM" wrote in message
...
Yes, I can believe that. But having experienced that tremor as the
first in my life,


SNIP

Totally mind-boggling to me, that tremor last night.

Sorry to highjack your post, but am I alone in 'Tremors' being my
favourite all time film?


First earthquake I noticed was the Lleyn Peninsula one back in 1984. The
building I was in (had got in to work very early) was a concrete 1950s
thing in Fleetwood. When trolleys were pushed up and down the corridors
the whole building sounded (and to a very minor extent, felt) like an
earthquake. Funnily enough, the earthquake sounded and felt like a
trolley... but a very big one. :-)

I saw it many years ago knowing absolutely nothing of it beforehand.
Brilliant. (Not so sure I would wish to view it again - case of right
film, right time.)

Damn sight better than Dune. Which should have been sunk in Waterworld.


Well, I liked the sets in Dune but the screenplay and the complete
*******ising of the story at the end were fairly breathtakingly awful. And
am I alone in thinking that the casting of Sting and Kyle McLachan (assuming
they were the only two available) was the wrong way round? Waterworld just
exists really.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

--
Rod



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On Thu, 28 Feb 2008 00:29:50 +0000, dave wrote:

On Wed, 27 Feb 2008 20:54:03 +0000, MM wrote:

On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:


"MM" wrote in message
...


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.

Even more solid when it falls on you :-(


Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM

I agree entirely with your sentiments on this. The amount of energy
needed to do such a thing is incredible! I thought about a simple
man-made task say of shoveling some soil for a few feet - then to
think of most of the whole country wobbling for a few seconds - gives
some practical idea of the scale/energy involved. Amazing.

Almost inspired me to start building one of these...
http://users.viawest.net/~aloomis/seismom.htm

but I guess would need a PC running all the time as a data-logger.
It could be quite fun (in an anorak kind of way). Maybe we could setup
a UK amateur network of sites :-)


I can tell that you think a bit off-the-wall, like I do all the time!
Imagine being able to harness earthquake power to drive a generator!
Or lightning, for that matter.

MM


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On Thu, 28 Feb 2008 02:26:30 -0000, "Clive George"
wrote:

"MM" wrote in message
.. .

Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation.


Well, interestingly enough, not necessarily.

If you're trying to shift rock, eg for road building or quarrying, you use
explosive. Put it near the surface and you get a bang and lots of little
bits of rock flying anywhere - but not much volume shifted.
Put it deep, and it looks a lot less spectacular - but shatters rather more
rock, provided you put enough in.

So if you go deep enough, you'll end up with a shock wave, ie earthquake.
See underground nuclear tests - how do you think they're detected? Locally
stuff is pulverised, but futher away it's more like what you want.

But yes, it is an interesting reminder of the scales involved in plate
tectonics - which is significantly larger than what we experienced last
night.


I suppose it isn't actually power as such that shifts the surface of
the earth we happen to be on at the time when an earthquake or tremor
happens, but simply the effect of gravity on very large masses of rock
miles down.

MM
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"David Hansen" wrote in message
...
On Wed, 27 Feb 2008 09:11:16 +0000 someone who may be MM
wrote this:-

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak?


That's partly it. If one part of the land on which the house is
built moves one way and the rest of the land moves the other way
then the house will be re-arranged.

So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?


At the low energies of this relatively minor earthquake. At higher
energies more buildings are not able to cope with the shaking.

Not all buildings are the same, but as a generalisation the better
built will stand up better. In an areas prone to large earthquakes
some buildings have now been built with active systems to lessen the
effect of earthquakes, for example some tall buildings in Japan.


In San Francisco the footings have to be exactly 49 foot deep.

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MM wrote:
On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:

"MM" wrote in message
...

Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.

Even more solid when it falls on you :-(


Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM


A 15km deep atomic bomb would have had the same effect by and large.

Google 'tallboy' bomb and the earthquake bombs that Barnes Wallis developed.

Used to get tremors all the time like this in Johannesburg. Blasting in
the mines and rock bursts..

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Doctor Drivel wrote:

"David Hansen" wrote in message
...
On Wed, 27 Feb 2008 09:11:16 +0000 someone who may be MM
wrote this:-

Is it because the whole "plate" on which the area is situated moves in
one lump, so to speak?


That's partly it. If one part of the land on which the house is
built moves one way and the rest of the land moves the other way
then the house will be re-arranged.

So the whole house moves this way and that, but
doesn't actually flex within itself? Is that how it works?


At the low energies of this relatively minor earthquake. At higher
energies more buildings are not able to cope with the shaking.

Not all buildings are the same, but as a generalisation the better
built will stand up better. In an areas prone to large earthquakes
some buildings have now been built with active systems to lessen the
effect of earthquakes, for example some tall buildings in Japan.


In San Francisco the footings have to be exactly 49 foot deep.

And thats just for the garden shed..

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MM wrote:
On Thu, 28 Feb 2008 00:29:50 +0000, dave wrote:
On Wed, 27 Feb 2008 20:54:03 +0000, MM wrote:
On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:
"MM" wrote in message


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.

Even more solid when it falls on you :-(

Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM

I agree entirely with your sentiments on this. The amount of energy
needed to do such a thing is incredible! I thought about a simple
man-made task say of shoveling some soil for a few feet - then to
think of most of the whole country wobbling for a few seconds - gives
some practical idea of the scale/energy involved. Amazing.

Almost inspired me to start building one of these...
http://users.viawest.net/~aloomis/seismom.htm

but I guess would need a PC running all the time as a data-logger.
It could be quite fun (in an anorak kind of way). Maybe we could setup
a UK amateur network of sites :-)


I can tell that you think a bit off-the-wall, like I do all the time!
Imagine being able to harness earthquake power to drive a generator!
Or lightning, for that matter.

MM


Lightning power has been done. But the strikes last an extremely
short time, yet the equipment has to handle the full strike energy,
and theres a lot of time between strikes. Those make for marginal
economics at best. The nearest thing I can think of to practicality
with lightning strikes is to use them to heat a pool. This minimises
equipment cost, and the large thermal capacity of the pool can
work with such an intermittent energy source. There is some place,
I forget where, where strikes are frequent, several per day, and thats
where these techs have been played with. But nothing is economically
competitive yet.


NT


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The Natural Philosopher wrote:

Largely I suspect the way blockwork developed, was that early man piled
up stones , then plugged the gaps with sand, then discovered the sand
washed out. But a bit of lime in the sand stopped it washing out.


Which is really all lime mortar is. Sand that doesn't wash away.;-)


yes, both mortar types are. The crush strength of sand is far
greater than that of lime or cement, those just hold the sand in
place so it takes the compressive forces.

Well if it used lime mortar, it certainly wouldn't have been held
together by that ;-)


FWIW lime mortared walls actually are more likely to survive
movement. Its one of the reasons SPAB et al advise its use in
buildings with little or no foundations.


NT
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Default Can some building guru explain how the earth can move but cause no structural damage?

On Thu, 28 Feb 2008 11:11:29 +0000, The Natural Philosopher
wrote:

Used to get tremors all the time like this in Johannesburg. Blasting in
the mines and rock bursts..


Do the houses withstand the constant buffeting? This the night before
last in Lincolnshire was once in 25 years.

MM
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On Thu, 28 Feb 2008 04:38:35 -0800 (PST), wrote:

MM wrote:
On Thu, 28 Feb 2008 00:29:50 +0000, dave wrote:
On Wed, 27 Feb 2008 20:54:03 +0000, MM wrote:
On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:
"MM" wrote in message


Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.

Even more solid when it falls on you :-(

Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM
I agree entirely with your sentiments on this. The amount of energy
needed to do such a thing is incredible! I thought about a simple
man-made task say of shoveling some soil for a few feet - then to
think of most of the whole country wobbling for a few seconds - gives
some practical idea of the scale/energy involved. Amazing.

Almost inspired me to start building one of these...
http://users.viawest.net/~aloomis/seismom.htm

but I guess would need a PC running all the time as a data-logger.
It could be quite fun (in an anorak kind of way). Maybe we could setup
a UK amateur network of sites :-)


I can tell that you think a bit off-the-wall, like I do all the time!
Imagine being able to harness earthquake power to drive a generator!
Or lightning, for that matter.

MM


Lightning power has been done. But the strikes last an extremely
short time, yet the equipment has to handle the full strike energy,
and theres a lot of time between strikes. Those make for marginal
economics at best. The nearest thing I can think of to practicality
with lightning strikes is to use them to heat a pool. This minimises
equipment cost, and the large thermal capacity of the pool can
work with such an intermittent energy source. There is some place,
I forget where, where strikes are frequent, several per day, and thats
where these techs have been played with. But nothing is economically
competitive yet.


Well, unleaded went up another 2p today where I live (near Spalding).
Now 106.9p in some places. Sooner or later, a 1000 litre oil tank
refill (domestic heating oil) will cost £1000, and people will be
becoming desperate for ANY alternative. Anyone who can design an
alternative power system now could be quids in later, even if SOME
leccy/mains gas still has to be burned to even out the cold/warm
periods.

MM
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Default Can some building guru explain how the earth can move but causeno structural damage?

MM wrote:
On Thu, 28 Feb 2008 11:11:29 +0000, The Natural Philosopher
wrote:

Used to get tremors all the time like this in Johannesburg. Blasting in
the mines and rock bursts..


Do the houses withstand the constant buffeting? This the night before
last in Lincolnshire was once in 25 years.


They semed to, Its no worse than having and underground station under
you, or living 20 yards away from a motorway..

Mind you whete the shocks were worst was the commercial area..all steel
and concrete. I didn't see any brick at all in Joburg. Concrete block,
or poured concrete, or wood.

MM



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Default Can some building guru explain how the earth can move but causeno structural damage?

MM wrote:
On Thu, 28 Feb 2008 04:38:35 -0800 (PST), wrote:

MM wrote:
On Thu, 28 Feb 2008 00:29:50 +0000, dave wrote:
On Wed, 27 Feb 2008 20:54:03 +0000, MM wrote:
On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:
"MM" wrote in message
Yes, I realise that this must be the case, but a brick building just
seems so solid when one is standing right next to it.
Even more solid when it falls on you :-(
Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM
I agree entirely with your sentiments on this. The amount of energy
needed to do such a thing is incredible! I thought about a simple
man-made task say of shoveling some soil for a few feet - then to
think of most of the whole country wobbling for a few seconds - gives
some practical idea of the scale/energy involved. Amazing.

Almost inspired me to start building one of these...
http://users.viawest.net/~aloomis/seismom.htm

but I guess would need a PC running all the time as a data-logger.
It could be quite fun (in an anorak kind of way). Maybe we could setup
a UK amateur network of sites :-)
I can tell that you think a bit off-the-wall, like I do all the time!
Imagine being able to harness earthquake power to drive a generator!
Or lightning, for that matter.

MM

Lightning power has been done. But the strikes last an extremely
short time, yet the equipment has to handle the full strike energy,
and theres a lot of time between strikes. Those make for marginal
economics at best. The nearest thing I can think of to practicality
with lightning strikes is to use them to heat a pool. This minimises
equipment cost, and the large thermal capacity of the pool can
work with such an intermittent energy source. There is some place,
I forget where, where strikes are frequent, several per day, and thats
where these techs have been played with. But nothing is economically
competitive yet.


Well, unleaded went up another 2p today where I live (near Spalding).
Now 106.9p in some places. Sooner or later, a 1000 litre oil tank
refill (domestic heating oil) will cost £1000, and people will be
becoming desperate for ANY alternative. Anyone who can design an
alternative power system now could be quids in later, even if SOME
leccy/mains gas still has to be burned to even out the cold/warm
periods.


They already are quids in. I am up 30% on my British Energy
(coal/Nuclear) shares..

At these prices Nuclear is already cheaper by about 25-30%..

At about 1 quid a liter, nuclear electric heating will be cheaper than oil.

Just think. No more burners, fans, flues, pilot lights, CO2 checks, CO
checks..Just a nice fat immersion heater.

I can't wait.



MM

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Default Can some building guru explain how the earth can move but cause no structural damage?


"The Natural Philosopher" wrote in message
...
MM wrote:
On Thu, 28 Feb 2008 04:38:35 -0800 (PST), wrote:

MM wrote:
On Thu, 28 Feb 2008 00:29:50 +0000, dave wrote:
On Wed, 27 Feb 2008 20:54:03 +0000, MM wrote:
On Wed, 27 Feb 2008 16:03:44 -0000, "Mary Fisher"
wrote:
"MM" wrote in message
Yes, I realise that this must be the case, but a brick building
just
seems so solid when one is standing right next to it.
Even more solid when it falls on you :-(
Yes, I can believe that. But having experienced that tremor as the
first in my life, I just marvel at the way mother nature can gather
enough energy to wobble an entire country a few inches this way and
that. It is to me as fascinating as trying to explain television to
Charles Dickens would have been. There is nothing comparable that is
man-made. Explosives would merely result in devastation. Imagine
trying to mount, say, a whole village (just a village, not an entire
country!) on some kind of manufactured plate, then inventing some
device that could extert the energy needed to shift it like an
earthquake can. I don't think human beings could ever devise such a
device. Totally mind-boggling to me, that tremor last night.

MM
I agree entirely with your sentiments on this. The amount of energy
needed to do such a thing is incredible! I thought about a simple
man-made task say of shoveling some soil for a few feet - then to
think of most of the whole country wobbling for a few seconds - gives
some practical idea of the scale/energy involved. Amazing.

Almost inspired me to start building one of these...
http://users.viawest.net/~aloomis/seismom.htm

but I guess would need a PC running all the time as a data-logger.
It could be quite fun (in an anorak kind of way). Maybe we could setup
a UK amateur network of sites :-)
I can tell that you think a bit off-the-wall, like I do all the time!
Imagine being able to harness earthquake power to drive a generator!
Or lightning, for that matter.

MM
Lightning power has been done. But the strikes last an extremely
short time, yet the equipment has to handle the full strike energy,
and theres a lot of time between strikes. Those make for marginal
economics at best. The nearest thing I can think of to practicality
with lightning strikes is to use them to heat a pool. This minimises
equipment cost, and the large thermal capacity of the pool can
work with such an intermittent energy source. There is some place,
I forget where, where strikes are frequent, several per day, and thats
where these techs have been played with. But nothing is economically
competitive yet.


Well, unleaded went up another 2p today where I live (near Spalding).
Now 106.9p in some places. Sooner or later, a 1000 litre oil tank
refill (domestic heating oil) will cost £1000, and people will be
becoming desperate for ANY alternative. Anyone who can design an
alternative power system now could be quids in later, even if SOME
leccy/mains gas still has to be burned to even out the cold/warm
periods.


They already are quids in. I am up 30% on my British Energy (coal/Nuclear)
shares..

At these prices Nuclear is already cheaper by about 25-30%..

At about 1 quid a liter, nuclear electric heating will be cheaper than
oil.

Just think. No more burners, fans, flues, pilot lights, CO2 checks, CO
checks..Just a nice fat immersion heater.

I can't wait.


Nor can the landlords who have to pay CORGI each year for a certificate.

Adam

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Default Can some building guru explain how the earth can move but cause no structural damage?

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Doctor Drivel"
saying something like:

In San Francisco the footings have to be exactly 49 foot deep.


That's a miner issue.
--

Dave
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Default Can some building guru explain how the earth can move but cause no structural damage?

On Thu, 28 Feb 2008 16:30:59 +0000, The Natural Philosopher
wrote:

They already are quids in. I am up 30% on my British Energy
(coal/Nuclear) shares..

At these prices Nuclear is already cheaper by about 25-30%..

At about 1 quid a liter, nuclear electric heating will be cheaper than oil.

Just think. No more burners, fans, flues, pilot lights, CO2 checks, CO
checks..Just a nice fat immersion heater.

I can't wait.


Fuel cells? What about them? Don't we keep getting told that these
will be the power of the future and our car exhaust pipes will pump
out steam and nothing else?

MM
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Default Can some building guru explain how the earth can move but causeno structural damage?

Huge wrote:
On 2008-02-29, MM wrote:
On Thu, 28 Feb 2008 16:30:59 +0000, The Natural Philosopher
wrote:

They already are quids in. I am up 30% on my British Energy
(coal/Nuclear) shares..

At these prices Nuclear is already cheaper by about 25-30%..

At about 1 quid a liter, nuclear electric heating will be cheaper than oil.

Just think. No more burners, fans, flues, pilot lights, CO2 checks, CO
checks..Just a nice fat immersion heater.

I can't wait.

Fuel cells? What about them?


What about them? The fuel to run them has to come from somewhere.


And they don't run cool either..



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Default Can some building guru explain how the earth can move but cause no structural damage?

In article ,
The Natural Philosopher writes:

However the tensile strength of cement approaches that of bricks..


Cement is only used as concrete or mortar, but it's irrelevant
as tensile strength of both is too low to be used in building.
Walls flex because they fail in tensile strength.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
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Default Can some building guru explain how the earth can move but causeno structural damage?

The Natural Philosopher wrote:
wrote:
The Natural Philosopher wrote:


Largely I suspect the way blockwork developed, was that early man piled
up stones , then plugged the gaps with sand, then discovered the sand
washed out. But a bit of lime in the sand stopped it washing out.


Which is really all lime mortar is. Sand that doesn't wash away.;-)


yes, both mortar types are. The crush strength of sand is far
greater than that of lime or cement, those just hold the sand in
place so it takes the compressive forces.

Well if it used lime mortar, it certainly wouldn't have been held
together by that ;-)


FWIW lime mortared walls actually are more likely to survive
movement. Its one of the reasons SPAB et al advise its use in
buildings with little or no foundations.



However the tensile strength of cement approaches that of bricks..


Its far higher than lime, but mortar tensile strength doesnt seem to
have much effect on building survival in movement in UK. I really
doubt British earthquakes are strong enough to move a building
fast enough to put it in tension, not when its a brick house weighing
a hell of a lot. If that did happen, loads of old lime mortared
houses
would be collapsing in quakes, and they dont, so I conclude it
doesnt happen.

Timber frame structure compressed joints go into tension in
countries with hurricanes and quakes etc, but even with those
here it not necessary to use ties round the joints. Re brick wall
ties in UK, I'm not sure they would make a lot of difference.

The fact that so little building collapsing occurred in the quake
tells
me the only things that fell down were things where the mortar was
totally and utterly shot, with nothing more than gravity holding the
chimney bricks in place.


NT
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