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Pipe Thrust Forces

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Pipe Thrust Forces

I know Lusk recently posted some files on this, but it was not really what I was looking for. I am trying to be able to generate a table of thrust forces at select junctions in my pipeline. Currently, it is set up for one pressure, but I want to evaluate multiple scenarios in this sheet. Pressure for steady state, test, surge (e.g. 20, 50, 35). The middle one only has a static component, but the others require analysis. The other problem I need to figure out, may be a programing issue, is the restraint for a dead end. The X component using 90 degrees is correct; however, you plug in 0 for your angle and the result is 0. Functions, programming, etc. are all fair game. I'd like a CSV dump to send to a spreadsheet when all is said and done. Your help is greatly appreciated in

24 REPLIES 24

Re: Pipe Thrust Forces

Worked on the file last night. Here is my latest file.

MathCAD 15 M030

Re: Pipe Thrust Forces

Beta of zero degrees means a straight pipe. Where will the thrust come from?

Re: Pipe Thrust Forces

For situations with no flow (velocities = 0) there should be no external forces--pressure causes stresses and strains, but there are no unbalanced forces.

Re: Pipe Thrust Forces

Fred, not no flow...no angle, as in a dead end. I think this needs to be a program loop. If b=0 only PA applies.

I think that this whole sheet can be made into a function with a program loop.

Re: Pipe Thrust Forces

ELSID wrote:

Fred, not no flow...no angle, as in a dead end. I think this needs to be a program loop. If b=0 only PA applies.

I think that this whole sheet can be made into a function with a program loop.

Or you could add this condition to F.sx and F.sy for simplicity.

Putting the whole sheet into a program loop will make it very complicated and difficult to check. The current layout is the better option IMO.

Re: Pipe Thrust Forces

ELSID wrote:

I'd like a CSV dump to send to a spreadsheet when all is said and done. Your help is greatly appreciated in

Can you use WRITEEXCEL function for this?

Re: Pipe Thrust Forces

If you have a dead end, by definition (and the continuity equation) there is no flow. And all of the "end cap" pressure would normally react at tension in the pipe wall.

If you're thinking of "water hammer," that's a wave phenomenon, not flow.

Re: Pipe Thrust Forces

Fred Kohlhepp wrote:

If you have a dead end, by definition (and the continuity equation) there is no flow. And all of the "end cap" pressure would normally react at tension in the pipe wall.

Correct and would only create stresses if the pipeline is restrained.

Re: Pipe Thrust Forces

Mike, there was no attachement or function. I am having an issue with the B=0 as my loop is still calculation 0 instead of 80 KIP. See F.sx in the attached

Fred, I have a straight run going into a vault using a thrust collar. Structural is asking for the thrust force at the the collar to design the concrete; hence the angle B is zero.

I hate the scalar error in MathCAD. Help? F.sx second value is supposed to be 80 KIP. Updated the file