Re: Friction Effects in Piping Systems

From: <Christopher>
Date: Wed Apr 23 2003 - 16:18:00 EDT

>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 <a href="/group/PipingDesign/post?postID=Zb-O3k3xIZMH_nlFkXB5-Sq8eSvdiSSQ62q6mHqDcERfoj6BewMY3n58RJiNamT0cJEOIT8jgViI_2N8CLM">chrisw@skypoint.com</a> | this distance" (last words of Gen.

___________________________| John Sedgwick, Spotsylvania 1864)

<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a> Received on Wed Apr 23 16:18:00 2003