RE: Anchor Forces & Moments

> it is important that the pipe stress engineer understands a little
>about the design of the supports, and conversely, the structural engineer
>understands a little about the pipe force/moment design. Without this
>overlap of understanding, it is all too easy to produce an inefficient
>overall design.

Without careful coordination it's also possible for things to drop through the cracks. Things that may seem natural for one discipline aren't necessarily natural for anyone else. I've gotten into a couple of situations where someone doing the piping just assumed that a particular piece of equipment would act as an anchor. The equipment was a sheet metal air-to-air heat exchanger, which might have supported the dead weight, but not much else. The equipment manufacturer may or may not have told someone about load limitations on his box--no one remembered when the question of seismic loading came up, way down the line after everything had been pretty much set in concrete. Turned out that the equipment was OK with the assigned seismic loading, but good reason to believe that the piping was a lot more flexible than originally thought, because the support which was assumed was a lot more flexible than assumed.

The moral is that none of us works in a vacuum. Say what you want about 'not my job,' or 'just following orders,' but the person who's ultimately responsible for a disaster is the person or persons who could have prevented it. And it's so easy to prevent problems by checking with other disciplines about proper details or the actual intent of a design, rather than just assuming whatever's convenient at the moment.

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