Concrete Pipe Saddles Restrained Piping Systems

[minorchord2000]

I am a structural engineer and have been tasked to design concrete pipe supports (saddles) founded on soil. I get conflicting information regarding the unbalanced forces acting along the longitudinal axis of the pipe, i.e. restrained fittings versus unrestrained fittings. The guy who laid out the piping system tells me that there are no unbalanced forces on the pipe line in the direction of the pipe axis and that the only load to resist is the vertical load tributary to each pipe support saddle.

The pipe system is steel pipe carrying water at pressures between 10 psi and 180 psi.

Is this, in fact, the case?

 

[bimr]

That is correct for welded pipe. Welded pipe is a restrained.

http://www.steeltank.com/Portals/0/pubs/Welded Steel Pipe 10.10.07.pdf

 

[rconner]

Additional references that may be of interest in your steel pipe on supports design work are AWWA Manual M11 for steel pipe as well as ASCE MOP 79 for steel penstocks (that has undergone revision not long ago).