Re: Friction Effects in Piping Systems

>Do you have a clear design criteria for the friction
>load?

The closest I can come to a clear criterion is that I never depend on friction to help. But as it's been said a couple of times in this thread, friction needs to be assessed intelligently case by case--there's no friction cookbook with a one-size-fits-all recipe.

Sometimes you have to make a couple of passes, sometimes with high friction sometimes with low friction. That's what was needed with free-standing spent fuel storage racks. Low friction gave reduced base shears and lower stress, since the racks were free to slide; high friction gave lower sliding displacements but greater uplifting displacements and higher stress.

If you're looking for friction to act as a restraint, say to support a span against lateral seismic motion, forget it.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)