Hello fellow Stressers!!

Do we need to manually input the hydrostatic compressive end cap force for submerged piping, say for a long horizontal pipe lying on a sea bed?

Thanks & Warm Regards,

Is the other end of the pipe somehow not being exerted onto by an equal and opposite hydrostatic compressive force?

Thanks Michael for the input. In this case, the input will be on a case by case basis depending on piping configuration and restraint types on the long run. If it is restrained in the axial direction in the middle, then maybe need to consider?

Any other opinion is greatly appreciated. Just correct any wrong statement I've made.

Cheers!!!

Consider a beach ball on the surface of the water. Consider the same beach ball at a depth of 1000'. The beach ball will be compressed on all sides semi-equally. Technically, the top will be compressed ever so slightly less than the bottom, based on the rho*g*h equation, where in this case, h is the diameter of the ball.

Consider now an extremely long idealized run of pipe, in the horizontal. It, too, will be compressed at the ends, equally, such that the displacement at the center will be 0, however, the ends will displace.

However, let's not assume we're analyzing the entirety of the line. Let's say we're only looking at 1/4th of the line. Ideally, our "partial analysis" will match "ideal analysis of the whole line." Our "partial analysis" should include this compression.

However, I contend that we should not view the compression of the pipe through the lens of "forces added to the ends," but rather an analog that we deal with everyday: temperature.

As we exert pressure to the outside of the pipe, it compresses and shrinks not terribly unlike that of temperature contraction. Do we expect monstrous loads onto supports and the like from a few degrees colder? Not really.

Note that this is only an analog for determining restraint loads.

To my knowledge, I know of no particular guidance of adding external pressure to internal pressure to thermal and occasional loads, except I know of no such inputs in CAESAR. ASME B31.8 might have additional information.

Thanks Michael for additional input. Actually, I've run a sample pipe and the result is negligible compared to the internal pressure and thermal load.

Any other opinion is greatly appreciated.I think the impact on the loading will not be much.

Just correct any wrong statement I've made.

Cheers!!!