Structural Job 1

[n39]

Hi everyone, so I met this person who wants to consult to me about something.
As a structural engineering, I have no idea what kind of "structural" check needed to be done in this sinker pipe lines. It was obviously placed underground, and no structural components were holding it. If it was place upper ground and was supported by a bridge, and I am sure it is my job to calculate the bridge structure capacity. But I don't think this type of analysis correspond to structural calculation.

What are you thoughts about this, and if you are agree with me, how do I told the guy that he probably need to find a geotechnical engineers instead.

Thank you

 

[TLHS]

Ask them what they're looking to have done and what they want you to be responsible for? I have done lots of buried pipe work, but it falls in the grey area in-between land of structural, general civil, geotechnical and mechanical piping work. If you have the right experiences in one of those disciplines, you might look at this type of work.

Once you find out what they want, if you don't have the experience or comfort level, don't do it.

 

[n39]

They were asking to calculate for the stress pipe, I was thinking using ABAQUS to calculate the stress on the pipe due to soil. But I have narrow knowledge about soil, and I am not sure I will be able to calculate it. But what you said is correct, this kind of work falls in the grey area between soil and structural engineering
TY TLHS

 

[LittleInch]

Tell them to ask a PIPELINE engineer, not a piping engineer.

What's the issue exactly that anyone needs to "check". All looks pretty straightforward to me / no issue to check.

It's only if you're getting a large change in temperature or the ground sinks do you have a stress issue.

"but it falls in the grey area in-between land of structural, general civil, geotechnical and mechanical piping work." errr, no, that's what pipeline engineers do....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Asking ABAQUS to do anything on this pipe is using a very large hammer to crack the smallest nut you've ever seen. IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[ThomasH]

If you have access to ABAQUS you can use it. But it is a beam on a flexible bed so you need the beam section and the bedding module. Then you can also do a hand calculation or some type of frame software to check the stress.

 

[LittleInch]

There is no stress here. It's not a flexible bed. Its a pipe inside a sleeve under a "river" / stream (though unclear how the sleeve / casing is installed).

This is a non issue. I've been designing pipelines for >30 years and I've never even looked at a stress issue to do with a river crossing. Road / rail yes, but not rivers.

It's also a typical drawing so good luck in deciding how long the crossing is.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[HTURKAK]

This is buried pipeline and you are expected to check the stresses for the sleeve pipe subject to external loading ( water , soil pressure , uplift...) and for the pipe ( internal pressure, external loading ...)

In order to get the concept , i will suggest you to look ;

- AWWA Manual 11 , Steel Pipe- A Guide for Design and Installation,

- ASCE Manuals and Reports on Engineering Practice No. 119 (Buried Flexible Steel Pipe Design and
Structural Analysis,

- Buried Pipe Design (By A. P. Moser ,Steven Folkman )

And also the following doc. free of charge ..

In past, i have prepared Excell spread sheet to check the buried pipe stresses.. You may develop also ..








Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[LittleInch]

Of course you check it / design it, but it's very straight forward pipeline design here. Someone somewhere is trying to make a lot more of this that there is.

And in most codes nowadays you don't install casings or sleeves unless you really have to, even if it is trenchless.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[n39]

LittleInch
Thank you for your responses, it was really helpful.

ThomasH
I guess, I'm going have to agree with LittleInch that asking a pipeline engineers is better solution.

HTURKAK
I will make sure I check on the books and codes you have suggested. Maybe it can give me some insight whether this was really my job or they should ask for someone else.

Thank you everyone