constrained pipe wall buckling

[pad75]

It will be grateful to you if you clarify the doubt as given
Below.

Whenever cross-country pipe crosses roads/tracks, it is going through a culvert. Actually, pipeline is completely
buried at culvert locations and in those cases soil and pipe couple together to resist buckling forces. These buckling forces are depends on the stiffness of pipe and soil. In case relative stiffness between pipe and soil at
Culvert location causes buckling at proceeding horizontal pipelines. Is it require to put restraints at culvert locations if yes what special type of support to be used
to overcome buckling effects. Is there any effect in buckling if a use 30 deg 18d bend (6 inch fuel gas pipe) in place of 45 deg 5d bends? Kindly reply.

Regards
P.Padmanaban

 

[yogibear1]

Thrust restraint theory is pretty straight forward but practically it has several interacting factors; it's all about vectors and opposing thrust forces that can separate the joint. A short answer to your question: yes, apply thrust restraint if the bury depth is not adeqate; and the number of joints to restrain either side of a bend or any change in direction, varies with the angularity of the change in direction of flow. A dead end would produce the most thrust, a 30 degree bend would have less thrust than a 45 degree bend.