Point Load on Pipe

[Rabbit12]

I have a situation where we have large diameter S10 stainless steel pipe that will be supported off a wide flange. My reviewer made a comment to consider the reaction on the wall of the pipe to make sure it doesn't bend our pipe wall.

I thought that would be relatively simple using AISC Chapter K. However, Table K1.1 is only applicable for D/t ratios of 40 or less. We have a D/t ratio of 91.

Are there any other standards for this type of check?

 

[JAE]

We've had to go the FEA route on large pipes.



Check out Eng-Tips Forum's Policies here:
faq731-376

 

[KootK]

Maybe look into the cold formed metal standard?

Worst case scenario, maybe you check it out as though it were a flat plate with no curvature and assume that's conservative.

Pipe wall bending = wall local buckling right?

I suppose that you could also detail your way out of trouble. Thick base plate or a split HSS round of similar dimensions as a stiffener in the beam etc...

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[KootK]

I think that I may have misunderstood the orientation of your pipe. I was thinking of a reaction parallel to your pipe walls. The reaction's really perpendicular to the pipe walls, right?

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[Rabbit12]

Koot, it's parallel to the pipe run. Similar to the "Longitudinal Plate T- Y-, and Cross-Connections" in Table K1.1 in the AISC manual.

 

[WARose]

You may want to try the HSS manuals. (Not sure if they make them anymore.)

Another resource might be a pressure vessel handbook. But that D/t ratio is kind of in the middle between AISC's world and the pressure vessel world. FEA might be a good backcheck for whatever method you go for.

 

[dhengr]

Rabbit12:
Take a look at Roark’s book for rings and pipe under various loads. Also, look at “Tubular Steel Structures, Theory and Design,” by M.S. Troitsky, Pub.by the Lincoln Arc Welding Foundation. Also, look at saddle supports for horiz. tanks, and various papers on pipe supports in general, by ASME and others. Of course, a simple FEA might be in order, as might a simple conforming/shaped repad or doubler pad with some friction reducing material btwn. the pad and the pipe.

 

[Rabbit12]

dhengr, are you referring to Roark's Formula's for Stress and Strain book?

 

[dhengr]

yes

 

[JStephen]

If the loaded area is circular or rectangular, there are methods available for checking stress in the tube, see WRC 107, WRC 297, etc., and these are implemented in some of the vessel software. For a line load, Bednar's pressure vessel handbook has an approximate formulation that can be very handy.

 

[UcfSE]

For tubular connections outside of Chapter K, we go the FEA route.

 

[TGS4]

This is a concern about the pipe, correct? If so, I would highly recommend that you secure the services of a mechanical engineer experienced with pressure vessels and piping stress evaluation. Depending on whether the pipe is full of liquid or not, the worst-case scenario may be with zero pressure, with a tendency to buckle the pipe. Depending on what you mean by "large diameter" (D/t of <100 is typical for most piping installations), a reinforcing pad on the bottom of the pipe may be cheaper than analysis.

 

[LittleInch]

The relevant piping code I(ASMe B 31.3?) might be of use here.

a lot depends on the other loads on the pipe and a piping stress analysis tool like Caesar is possibly needed.

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

 

[XL83NL]

I concur with TGS4. As to the OP's 1st question, get a copy of Peng & Peng's Pipe Stress Engineering, if thats (a part of) your scope of work. Refer to paragraph 6.7, "SUPPORT OF LARGE PIPES"

 

[NOLAscience]

Put a saddle under the pipe so that the point load is distributed over, asy, 75% of the pipes diameter, and of a width that is sufficient to reduce stress.

 

[Rabbit12]

NOLA, that's what I ended up doing.