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Steel Pipe Stress

Steel Pipe Stress

Steel Pipe Stress

(OP)
Hi all,
New to this community.
I am going through a problem that I cannot figure out how to solve. I need to find stress and evaluate whether pipe/pips suppoetis safe.

The steel pipe needs to be installed with Horizontal Directional Drilling. In this method, a long welded string of pipe(approx 1200 feet of 36 inch dia) will be pulled into the hole. To achieve this, pipe needs to be lifted up to make it align it to a borehole(borehole is 10 degrees to Horizontal, ground surface where pipe is to be lifted at is sloping down, with borehole being at higher elevation and other end of pipe being at lower elevation). The pipe string will be lifted with string(attached to crane) at maybe 2 location along the length(Thats what I need to design/calculate). So how do I go about doing this calculations? There will be self weight of pipe, and load at supports of crane.what codes/calculations do I use? Can I use beam/simply supported beam? I need to know how to calculate the stress induced under such conditions and find number of supports/cranes required along the length. Thank you everyone.

RE: Steel Pipe Stress

What is the ground surface, soil, concrete, steel plate - mainly concern friction? What is the procedure for pipe pulling - lift a segment at a time, or..? What is capacity of the pulling machine?

RE: Steel Pipe Stress


Dear Pkandel ;

There are expert companies for HDD business. Nowadays, there is a tool GOOGLE .. write ( Horizontal Directional Drilling ) and search the web.. one of the descriptive video link is ;

https://www.youtube.com/watch?v=hPsghHCkXlg

Is this thread for a real question? If it is, the calculation report is prepared by HDD expert company with some inhouse data.

The spool 1200 ft is prepared and laid on roller supports and lifted some portion with sideboom cranes( while remaining still on the roller supports ).

You may ask specific questions after watching this video or better, there is another forum ( Pipelines, Piping and Fluid Mechanics engineering ) to post this thread to get more responds...

RE: Steel Pipe Stress

What you are doing is fine for estimating, but real installation must be designed by the HDD contractor to have any creditibility.

These are not usually simple supported. Continuous beam of 3, 4 or more supports will probably be necessary. Do not yield the pipe or create local buckles. First consider defining maximum allowed curvature, then you can draw any pipe profile as needed, as long as it falls inside that limit and has the appropriate number and location of support points. That depends on sideboom or cranes available and their capacity. A pipeline-beam will take a cubic spline curve profile between all supports. Bending moment will be proportional to resulting curvature at any point.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

RE: Steel Pipe Stress

The sketch below just to show the magnitude of this task as described.

[Correction] P(min)= 60 Tons



I don't think this the way how Directional Drilling does.

RE: Steel Pipe Stress

P KANDEL

You're doing this all wrong.

10 degrees is too big as an entry angle. 5 to 7 is more normal to avoid a huge height of crane

The pipe should be a curve of around 500 D min to avoid overstress and buckling. For a 36" pipe you probably need a support every 50 to 70m.

You need to contact some companies that do this for a living to avoid making some huge errors. IMHO.

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

RE: Steel Pipe Stress

You can have a snake configuration with forward and reverse curves
Its not lifted as a straight pipe.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

RE: Steel Pipe Stress

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

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