Deflection Diagrams

[440MoPar]

I want to display the deflection diagrams of my structure in RISA, but RISA is not even allowing me to check the boxes. How do I get RISA to display the deflection diagrams. (FYI: I have solved the structure in RISA.)

Thanks!

 

[bootlegend]

Did you run a Batch solution?
You can't display a deflected shape for and Envelope solution.

 

[440MoPar]

Well, I guess I have not been running a batch solution and am not exactly sure where to look either...

How do I determine this. Thank you.

 

[440MoPar]

I just looked through RISA help, it states:

In the Show Deflected Shape For... section of the tab you may specify that a deflected shape be drawn in the current model view based on either a load combination (if a single or batch static solution has been done) or a mode shape (if a dynamic solution has been done). You can control the magnification of the deflections with the Magnification Factor text box and specify whether an undeflected shadow is to be shown by checking the Include Undeflected Shadow box. For batch solutions you must choose which combination you want to view in the Combination To Use For Results Display drop down list.

It doesn't say that you need to perform a batch solution only in order view deflections. Maybe I am doing something else wrong?

Thanks.

 

[440MoPar]

I think I just figured out what you were talking about, johnny cash.

After you click solve, you select "Batch Solution of Marked Combinations" under solution choices.

However, I have moving loads (structural framing members for an overhead crane) and it brings up an error message:

"Load Combination 1 has a moving load included. Currently the program can not do a batch solution with moving loads.

Error code = 2046"

Any advice, besides just removing the moving loads and putting any equivalent static load at an anticipated worse case area?

Thanks again.

 

[bootlegend]

You could probably run the moving load case as a single case solution. I don't know for sure as I don't think I have ever used the moving load function other than just tinkering with it.

I usually try to pick the worst location for the load and run it as a static load case and include a dynamic/impact load increase factor if I consider it necessary.

From what I remember the moving load solver takes a really long time to reach a solution too.

 

[bootlegend]

Just saw the last sentence of your last post. So I gave the advice you didn't want to hear.

I would think you could easily model your situation as static.
A crane doesn't move that fast if it is supporting a design load anyway.

 

[JoshPlumSE]

There isn't a single deflected shape for a moving load. Rather there would be a different deflected shape for every position of the moving load.

Since there isn't a single deflected shape to display, RISA won't display any deflected shape.

Ideally, what you'd want to see is an animation of the deflected shape as the moving load transits through the structure. But, RISA just doesn't do that yet.

Josh

 

[440MoPar]

Thanks for the help, johnny cash.

JoshPlum: Does STAAD Pro do this?

Thanks

 

[JoshPlumSE]

I don't have much current knowledge about STAAD. But, from what I remember they do not. I think you'd have to look at a program that was more geared towards bridge design to see the deflections in this way.

 

[440MoPar]

Thanks for the posts everyone! I greatly appreciate your time and help!

 

[WillisV]

SAP will do it (the continuously updated animated shape for moving loads)