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Pipeline design for earthquake 2

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KevinNZ

Mechanical
Joined
Jun 12, 2003
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NZ
Can anyone recommend a good referance on designing above ground pipelines for Earthquake using modal analyis.

I am intersted in the correct way to model soil stiffness at anchours and friction on supports etc.

Thanks
Kevin
 
Modal analysis alone won't help you, this is just a "natural frequency" determination. You likely want to perform a "response spectrum analysis". Search the web for articles.

Here is a good starting point:
[URL unfurl="true"]http://www.americanlifelinesalliance.org/pdf/Seismic_Design_and_Retrofit_of_Piping_Systems.pdf [/url]

You may also find this particular topic discussed in texts on "Pipe Stress Analysis". Check out Amazon.com to see what they have available.

I presume you have some sort of software on hand to perform this type of analysis. Contact your software vendor, they may have a course available which addresses this topic.


Richard Ay
COADE, Inc.
 
KevinNZ,
Someone advise me to use MSS SP-127 as a reference. However, I do not have such document on hand. This may be helpful. Please share your experience.
 
KevinNZ,
I agree with Richay. The reference that he mentioned is excellent to start with. Presuming that you will be using a software to do this, you'll definitely need to gather the soil data (soil type, soil denstiy, angle of internal friction, ...)for the corresponding location in order to be able to model the soil stiffness as springs at your anchor points. For a pipeline your anchor points will most likely be the foundation of your concrete sleepers or foundation of your steel frames supporting the pipe.
Another key piece of information which is usually provided by the client but not always, is some sort of RESPONSE SPECTRUM curve for that region. The one commonly used in seismic analysis is the ARS (accel. resp. spectrum) curve. If the client is not providing this data, there are a number of benchmark "ARS" curves from recorded earthquakes, such as ElCentro, available in the literature published on this topic. Seismology and earthquake engineering is a vast field and I know that this thread won't answer all your questions. It is very important to apply the appropriate modeling techniques per case, and for that you need to first grasp the fundamentals of earthquake engineering and its governing parameters. If you know a civil or structural engineer, please, consult with them too.
There are a number of good structural and Piping softwares that you can use to develope a good simulation of your piping system, but I am not sure if I am allowed to name any names in this forum. The software that I use, has a number of ARS curves available in its databank and it also has an option for modeling soil stiffnesses for BURIED PIPES only. I understand that you're dealing with an above ground pipeline. You have to sort of fool the software and use its tools to develope a model which is closest to your scenario.
good luck
 
Please name the software for all of us to share your knowledge. Many name Autocad, Pipelpapk, PDS etc in threads. The forum is here to spread knowledge. Even some sales people put interesting threads up. If they are honest and say they sell stuff what is the problem?

 
TEAM MEMBER'S:

TECHNICAL NOTE: Reference to "DOE" this technical information will be available in MARCH 2006.
 
stainer

I am currently using CAESAR II (4.4) which is the pipe stress analysis software developed by COADE. It has a customized input module which really speeds up modeling of piping systems. If you use the available tools in this software properly, you can go a long way. O.K., I am gonna stop right here because if I go on this is gonna sound like a commercial. Anyhow, if you're curious enough, I am sure you can do your own search on the net and get more familiar with the available options in commercial softwares.
 
MSS-127 Bracing for Piping Systems Seismic-Wind-Dynamic Design, Selection, Application

John
 
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