• To: <seaint(--nospam--at)seaint.org>
• Subject: RE: STAAD Results interpretation
• From: Christopher Wright <chrisw(--nospam--at)skypoint.com>
• Date: Tue, 18 May 99 08:11:41 -0500
```>I'm trying to figure out the Fx, Fy, Fxy and angle ( for Print Element
>Forces) and is still in the process of doing so up to now. I hope you could
>help me out on this.
Although I'm certain the force convention is covered in the docs, this is
something you should dope out for yourself--it's the only way to verify
FEA results.

Run a simple problem with a known obvious answer like an end loaded
cantilever beam. Print out all the results. The Fx, Fy and Fxy numbers
should be immediately recognizable from what you know about the force
distribution in a cantilever. Just to be sure you put in the properties
correctly, check the end deflection from elementary theory. If the
effects of orientation aren't obvious, model the beam at a 45 degree
angle with the coordinate axes. Try it again with gravity loading so you
can see where that enters in. After you've figured it out for the
cantilever go back into your real problem and verify your conclusions by
checking equlibrium with a couple of elements. Draw a free body diagram
and apply the loads as you found them from your demo problem. Calculate
the resultant forces and moments and verify that the equations of statics
are satisfied. If you can't get no satisfaction, either you have the
blues or you've made a mistake applying the loads, guessed wrong for the
sign convention or there's a program bug at work (with the likelihood
pretty much in that order). If you can't do this equiibrium check, work
at it until you can; otherwise you'll forever be at the mercy of every
bug or documentation error the program has to offer.

Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw

```