Pipelines On bottom stability

[robb4]

Hi,

I'm involved in on bottom stability study of a offshore pipeline. Due to extreme enviromental loads we are thinking about use of mattresses to ensure the stability during design life.

Since the DNV codes (RP 305 and RP F109) don't consider this situation, do you have any reference or standard practices or calculation methodology for calculation of stability of system (pipeline + mattresses)?

Thank you for your support.

 

[BigInch]

The mattress does not contribute directly to the stability of the pipeline itself. The pipeline would still need to be weight coated for negative buoyancy. A mattress only prevents the erosion of underlying soil cover over the pipeline from washing away and exposing the pipeline to wave and rift current forces that might tend to leave the pipeline spanning too far, vibrating or allowing the currents to drag the pipeline laterally along the sea bottom.

The mattress must be made of components that minimize drag yet provide enough weight (weight in water) so that the mattress is too heavy to move when those drag forces from the wave and rift currents are acting on it.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

 

[BigInch]

BTW robb I almost didn't see your "pipeline" post in the Offshore Forum. Please post your future pipeline questions, on, or offshore, in the Pipelines, Piping and Fluid Mechanics forum.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso