Modeling a Structure Column in STAAD

[reno1051]

I have a HSS28x28x5/8 column and I do not know how to create that section in STAAD. I currently have a full 2D model of the structure and all the loads/properties (was previously used for design), but now I need to analyze the column with a hand hole in the column section. As far as I know, this has to be done in a 3D model. I was trying to get away with doing it in 2D and making nodes at the top and bottom of the hand hole and inserting the properties at that section but the torsional constant reduced from 227 in^4 for the full section to 6.09 in^4 at the hand hole.

So basically I am asking, how do I insert my own steel sections and how can I properly model this column with the hand hole? Or is there an easier way to go about this? The structure works without the hand hole and I need to make sure that it still will be sufficient with the hand hole and same loadings.

 

[SethGuthrie]

You can define shapes with a user table, or using the graphical user interface you can define new shapes under General tab - Properties - Define...

The program Help has a few important sections for you:
User Interface; Properties - Whole Structure dialog box
User Interface; 2.2.3.1 General | Property Page
User Interface; 2.3.7.1 Commands > Member Property submenu

Keep in mind, if you use a "General" prismatic member you can't perform a steel code check on that, only analysis.

 

[reno1051]

quick question...i was doing a live chat with the bentley support and they told me that staad cannot represent a hole in a section. i was planning on making a 3D model and putting the hole where it is. is this true? if it is, what program should i be using?

 

[SethGuthrie]

True you can't have a hole in a section along the length of a member. You can have a member in three parts, however, say a tube from 1-2, then a custom section with smaller properties from 2-3 and another tube from 3-4. Analytically it should be all right, but like I said before the "design" of the middle section can only be done if it fits one of the standard profiles. Conversely, and more accurately, you can model the whole thing using thin plates and do a stress analysis of the metal.

 

[reno1051]

hmm i guess i gotta figure out how to model the plate elements. Also, are there 'easier' programs instead of STAAD? everything i read, its just people complaining about it.

 

[SethGuthrie]

Most of the general purpose Finite Element Analysis and Design applications are similar in this respect. Some have subtle advantages here or there but the nuts and bolts are the same. Ram Structural System is the only application I can think of that actually designs a steel beam with a hole in it, but that's limited to Wide flange beams, not for tube columns.