S-lay

[S0606]

Hello,

Can anybody tell me how to find the maximum curvature of the pipeline during S-laying process. (Sag-bend curvature)

regards

 

[BigInch]

Assume a catenary curve and calculate tension required to maintain the beam bending stresses due to beam curvature + the tension load below total allowable stress.

"If everything seems under control, you're just not moving fast enough."
- Mario Andretti- When asked about transient hydraulics

http://virtualpipeline.spaces.msn.com

 

[S0606]

Hello,

Can you please give me more details how to do that as I have the tension, depth and pipeline specifications and I want to calculate the maximum sag-bend curvature.

Regards,

 

[S0606]

please I need it urgently

 

[BigInch]

M/I = E * (1/R - 1/Ro)

as described here,

http://www.grantadesign.com/resources/shapes/solutions/elastic.htm

Use a catenary equation describing the pipe from the stinger exit point, with a slope equal to the stinger exit angle, a catenary height equal to water depth - end of stinger depth below water and a pipeline slope at the mud line equal to 0.

The 1/2 catenary horizontal distance will vary according to the tension force applied. That changes the horizontal dimension of the catenary and now you can figure the curvature.

Pipeline axial and bending stress = TensionForce/Area_of_Steel +/-
M * c/I

M = Moment (due to curvature) from the M/I = E * 1/R
I = Moment of Inertia of the pipe section
c = distance from Neutral Axis (center of pipe) to the Outside pipe wall.

"If everything seems under control, you're just not moving fast enough."
- Mario Andretti- When asked about transient hydraulics

http://virtualpipeline.spaces.msn.com