Compressive Radial Load on Pipe
Compressive Radial Load on Pipe
(OP)
I am checking a 6" XS pipe in a crane lift configuration.
A 1.5" wire rope with a soft eye will be slung around each end of the pipe which is part of a skid holding a 50 000lb pump.
I'm trying to determine whether or not the pipe wall will buckle. The maximum sling tension is 38 350lbs.
A co-worker provided an unsubstantiated "Belt wrap formula" of Tension/Radius.
I have checked many formulas for a similar loading and have come up with differnet results.
If anyone can provide a definitive solution I will be eternally grateful.
Cheers!
A 1.5" wire rope with a soft eye will be slung around each end of the pipe which is part of a skid holding a 50 000lb pump.
I'm trying to determine whether or not the pipe wall will buckle. The maximum sling tension is 38 350lbs.
A co-worker provided an unsubstantiated "Belt wrap formula" of Tension/Radius.
I have checked many formulas for a similar loading and have come up with differnet results.
If anyone can provide a definitive solution I will be eternally grateful.
Cheers!





RE: Compressive Radial Load on Pipe
http://virtualpipeline.spaces.msn.com
RE: Compressive Radial Load on Pipe
http://virtualpipeline.spaces.msn.com
RE: Compressive Radial Load on Pipe
There are I-beams, which make up the sides of the skid, near both ends of the pipe. The webs are welded to the pipe wall. Thus the load from the pump is transferred to the pipe via the beams. It is not a point load at the centre of the pipe span.
The slings wrap around a 5" section of pipe that extends beyond the beam webs. Also the pipe is capped with an end plate. I'm not aware of the details of the plate.
I have to provide proof that the tension in the slings will not buckle the pipe so DNV will certify the lift. However, I've not been able to do this so far. At least not with the formulas I've found.
The belt wrap formula is the radial load I've been applying to the pipe to determine if it will buckle.
RE: Compressive Radial Load on Pipe
http://virtualpipeline.spaces.msn.com
RE: Compressive Radial Load on Pipe
Anyway the problem of a rope eye wound around a pipe can be attacked more or less as follows:
-from geometry determine the angle of contact of rope to pipe; as this will probably be larger than 180 deg, take 180 deg as a maximum
-assume a constant pressure acts on the contact and determine this pressure (a linear load in fact) by equating the vertical component of the distribution to your load
-now imagine that the same pressure will act on the full circumference: go to the first site below, and to Pipes -> Axisymm.loads -> Free-free -> Radial load. Calculate a section of pipe sufficiently long so that end effects are minor
-you now have a maximum compressive circumferential stress in the pipe wall to compare to the allowable compressive stress in a vessel wall subject to external pressure
This procedure should be quite safe, but I imagine that your pipe will be far from buckling, so you only need a rough check.
prex
http://www.xcalcs.com : Online tools for structural design
http://www.megamag.it : Magnetic brakes for fun rides
http://www.levitans.com : Air bearing pads
RE: Compressive Radial Load on Pipe
I'm not sure if I posted this image correctly. Hope this clarifies the situation.
I checked the section of pipe against ASME B31.3 Pipe Wall Thickness Under External Pressure. For 5 inches between stiffeners (i.e. web and end plate) I got a Maximum Allowable Pressure of 1515psi. My applied pressure is around 7750psi if I've calculated that correctly.
Thanks!
RE: Compressive Radial Load on Pipe
I would calculate the pressure as F/DL or 38350/6/5=1278 psi with your numbers.
With that formula the vertical resultant of pressure acting on the lower half of your pipe is equal to the load.
prex
http://www.xcalcs.com : Online tools for structural design
http://www.megamag.it : Magnetic brakes for fun rides
http://www.levitans.com : Air bearing pads
RE: Compressive Radial Load on Pipe
RE: Compressive Radial Load on Pipe
http://virtualpipeline.spaces.msn.com