Combined Section Wide Flange w/ Channel

[iv63]

I have created combined section (Wide Flange w/ Channel) using Section Wizard and exported it to STAAD as general section. How does STAAD perform AISC check code for this section?
Thank you,
iv

 

[JoshPlumSE]

I saw a presentation from STAAD about this 10+ years ago. What I remember is that they merely did an equivalent section code check. I'm not sure how they determined the properties of the equivalent section though. That will dictate how accurate (or inaccurate) the code check is.

My strong recommendation is that you only use what STAAD gives you as a starting point.... maybe for determining what forces, location and load combination will result in the worst case code check. Then YOU perform the code check by hand.

1) Use the A, I, J, and Z for the built up section.
2) The b/t ratio of the web will be the same as for the original I beam. b/t ratio for the flange is probably not going to be a problem. But, I'd base it on the combined t of the channel web and Ibeam flange, then on half the height of the channel. Noting that this this is a stiffened section on both ends.
3) For strong axis bending, I might neglect the flange tips of the channels from the properties (I and Z) of the section when doing my code check. If not, then I'd also look at the AISC section about compression buckling of the stem of a WT section.

That's all that immediately comes to mind.

 

[iv63]

Thank you Josh. I hope somebody from Bentley will chime in.
iv

 

[Sye123]

Section Wizard calculates the cross sectional properties of the built up section based on the geometry. When exporting the section as a General Section from Section Wizard to STAAD.Pro, the calculated properties are shown (for your reference) within the General Section form that is displayed within Section Wizard before the export happens. Once you provide the section name for the built up section and click on the OK button at the bottom of that form, the information is written down in a .upt file that can be read by STAAD.Pro as an external user table file. STAAD.Pro classifies the section based on the slenderness of the individual elements of the cross section and the section is then designed following the rules applicable for wide flanges.

 

[iv63]

Sye, so this section (Wide Flange + two Channels) STAAD treats as wide flange during design?
iv

 

[Sye123]

Yes it applies the same rules as you would apply when designing a wide flange. The cross sectional properties used are for the built up section.