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Topic Title: Designing For Earth Quakes
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Created On: 15 February 2012 01:40 PM
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 15 February 2012 01:40 PM
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stevefleming

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Joined: 25 July 2008

I was wondering does any one have any experience of designing building services in earth quake zones and can they advise of any guidance or standards that are available.
 20 February 2012 01:28 PM
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OMS

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Your looking at a subject that encompasses "seismically qualified non structural components and systems"

There may well be specific codes or standards depending on the building type and location and will usually set the design criteria (ie one in ten thousand year earthquake event of given magnitude).

Essentially what you are then trying to achieve is equipment that meets criteria for Design ground motion, Component Importance Factor and horizontal force/vertical force ratios amongst other things

It can get quite complex particularly in safety related systems

Not enough information on where you are or what you are trying to achieve to be more specific

Regards

OMS

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Failure is always an option
 27 February 2012 09:23 AM
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HarryJMacdonald

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A lot of stuff would have been published at the time of building Torness / Heysham power stations and probably Sizewell as well. How much is relevant to building services,(as distinct from major electrical installations) I don't know. The main thing I remember was that everything was taken off to a lab and shaken and also that we could not assume that the floor to ceiling height stayed the same, i.e. all columns had fixings in the ceiling that allowed for vertical movement.
 18 May 2012 08:38 AM
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buildingangel

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I'd Say Use really soft or really hard stuff

Roofing Services
 18 January 2013 08:23 AM
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JakeRoll

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Joined: 20 December 2012

I am not yet an engineer so i do not have any experience about that but... I have seen site and books that tackles about that thing. During my research I just found out ACM Facility Safety and I think it really helps. Just a thought.
 30 October 2013 01:59 PM
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christait

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BS EN 1998 for general use in the UK (note there are national annexes specific to the UK). This does not necessarily cover sites were other regulations may also apply, e.g. Nuclear, were licence conditions may be far more stringent.
 23 November 2013 02:13 AM
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Rowsell34

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It is a good idea to design a house for earthquake
 27 November 2013 10:31 AM
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kengreen

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hello,

Do bear in mind that there hardly exists a standard model of anything; there is always the chance of a bigger, or different, happening. This surely is a subject where you have to learn as you progress and try always to benefit from past failures - you will have "past failures". in such as earthquakes there can be no definitive design - it seems to me to be a worthy career that is doomed to disappointment!
Ken Green
 27 November 2013 05:31 PM
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OMS

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Isn't that what a postulated earthquake is based on Ken - a combination of historic and measured data and a mathematical model that extrapolates to the required design basis - say a 1 in 10,000 year or 1 x 10^-4 event at a given location.

From that model, the design can then extend beyond design basis to the cliff edge failure and demonstrate that there is sufficient margin to give confidence in the design.

There is nothing unworthy or disappointing in that - it's just another design challenge

Regards

OMS

-------------------------
Failure is always an option
 27 November 2013 05:43 PM
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kengreen

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OMS,

Absolutely true,

I did not mean to imply that there was anything unworthy just that, in circumventing the effects of earthquakes, you are battling a no-win situation?

Ken Green
 27 November 2013 06:33 PM
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OMS

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How no-win ?

I've been involved in the design of structures and services that have been exposed to real earthquakes and have survived, and provided great benefit to those who also survived but suffered injury, loss of homes, etc etc. Keeping hospital facilities standing and thier infrastructure intact and operational offers huge advantages to communities in earthquake situations.

I've also been involved in some of the engineering analysis of real earthquakes where it's true to say that even minor design changes could have had a benefit far beyond the actual value to implement - so adding to a pool of knowledge and experience data for others to use. Christchurch, New Zealand taught us how complex electrical infrastructure operates in real situations - so engineers now know how to keep the power on (or more of the power on) in given situations - not all of which are seismic

I'd say that was win-win

For sure they may be a bigger earthquake around the corner, than that designed for, but it would be a pretty extreme event, and no one said we could keep everyone safe all of the time - it's about keeping more people safe most of the time.

Regards

OMS

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Failure is always an option
 28 November 2013 10:37 AM
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kengreen

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OMS,

You may rightly claim a win-win situation when you have designed, constructed and proved an erection that withstands such as Krakatoa, the eruption that wiped Pompeii from the face of civilisation, those events of the past to see whose handiwork you need diving equipment and, while we are at it, a meteor impact?

Ken Green
 28 November 2013 11:10 AM
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OMS

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I disagree - we could design structures to withstand the most extreme events but there is no economic point in doing so.

Without doubt, we could escalate the next 10 posts to come up with more and more extreme conditions - but we would also have to admit that with each increase in severity, we would also see a decrease on probability and then factor in the geography.

If you know the likely meteor impact we could design for it - as it is, most meteor impacts are small and we tend not to design for something like Meteor Crater or Tunguska as probability shows us that it is a once a mellenia experience and even then it is just as likely to hit a totally unoccupied area as a densely populated one.

I guess my point is that of course we don't take into account the worst possible threat - but we do account for a large number of threats - It's what risk assesment and ALARP principles account for. It's a bit like saying we can't deal with an extinction event magnitude so therefore we shouldn't do anything at all ?

Regards

OMS

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Failure is always an option
 28 November 2013 03:46 PM
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kengreen

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OMS,

I am encountering increasing difficulty in trying to decide whether you share my thinking or perhaps you share my thinking. Surely I have made it clear that I don't believe at all that it is possible to design for survival under any conditions of disaster. The matter entails limits (i.e. safety margins, tolerances) and this is the area in which you face no-win situations and the attendant disappointments?

Ken Green
 28 November 2013 05:50 PM
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OMS

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I guess we see things differently then Ken - I have no disappointment in designing buildings to survive some events even if I know that they won't survive the most extreme events. It's basically what we face every day isn't it.

Regards

OMS

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Failure is always an option
 29 November 2013 08:30 AM
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ectophile

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Originally posted by: kengreen

OMS,



I am encountering increasing difficulty in trying to decide whether you share my thinking or perhaps you share my thinking. Surely I have made it clear that I don't believe at all that it is possible to design for survival under any conditions of disaster. The matter entails limits (i.e. safety margins, tolerances) and this is the area in which you face no-win situations and the attendant disappointments?



Ken Green


Perhaps OMS isn't such a pessimist as you. If you design a building, and a few years later it gets hit by an eathquake, doesn't fall down, and nobody inside gets killed, then to me that's a success.

It's still a success even though the building would have fallen down had it been hit by the biggest earthquake the World has ever known.

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S P Barker BSc PhD MIET
 29 November 2013 12:02 PM
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kengreen

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very true indeed ectophile,

But your weakness lies in that word "IF"; you forgot to turn over the penny and examine any alternatives? I object to your word pessimist - I believe in being a realist! What if the building DOES fall down?

Ken Green
 01 December 2013 06:22 PM
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sandip

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Research point of view past experience/data can lead a relation between intensity of earth quake with respect to failure of a structure of specific over all height / plinth level or other criteria.

Once such relations are established from past record then research work on the same line may produce little optimistic result.

However this is just one of the views.

Sandip Roy MIET
 01 December 2013 06:55 PM
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kengreen

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Roy,

I think you have taken us back into the matter of interpolation and extrapolation; both are rigourous techniques when kept within proper limits.

Of course we have no choice at all except to look at our painfully-gathered data and attempt to extrapolate into the realm of the biggest yet disturbance. That which I find in error is the idea that we can oppose the forces of nature - they can be truly beyond our ability to contain them; equally of course we can only do our best.

Ken Green
 02 December 2013 11:00 AM
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OMS

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Originally posted by: kengreen

very true indeed ectophile,



But your weakness lies in that word "IF"; you forgot to turn over the penny and examine any alternatives? I object to your word pessimist - I believe in being a realist! What if the building DOES fall down?



Ken Green


Well - at risk of prolonging this, we can reasonably predict how it will fall down - and elastic design and partial and progressive collapse are all techniques that are used.

So we take a building, we give it a damn good shaking (in a model) and we can see how it responds - bits might fall off, external services may be lost, but that doesn't make the building totally unuseable as a shelter building, as a first aid centre, as a control and command centre etc.

As I mentioned earlier, you can ascertain the design basis, you can ascertain the threats and the combination of those threats (for example sesimic event of predicted magnitude coupled with an extreme wind event, extreme hot or cold event etc etc, coupled with a potential sesmically induced fire event) - from there you can design for that condition, and you can design for "beyond design basis" to determine where the cliff edge of failure exists (if it does exist) and determine both the margins and the nature of how those margins influence the way in which the structure responds along with how the services respond.

So, if the building does eventually fall down that can be mitigated within the bounds of the postulated condition.

We certainly can't protect the building and occupants from all conditions - but that doesn't mean to say we can't offer that protection for some conditions, rather than do nothing at all.

If you want to be a realist then you need to consider what that means - it's not just a case of dreaming up the worst possible threat and saying if you can't meet that then do nothing - a realist uses the principles of ALARP I would have thought, for both deterministic and probabalistic assessment

Regards

OMS

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Failure is always an option
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