Calculate torsion on beam with bracing?

[bigrod223399]

I have a calculation that is capable of doing torsional analysis of an unbraced beam, but how about in the case where there are bracing elements at third points? There are almost no examples that I can find on this and virtually no piece of software can do this. Is it reasonable to use a force diagram and calculate/apply some type of ratio of torsion on unbraced-to-torsion on braced beam to check flange/web stresses?

 

[le99]

Internal braces act as a support with the proper joint releases of fixity.

 

[bigrod223399]

Internal braces act as a support with the proper joint releases of fixity.

I understand this part, but I guess my question or issue is that I'd like to try to avoid reinventing the wheel (as you may know, AISC's Design Guide 9 is very long-winded and doesn't cover this scenario). I have software that is capable of designing members in torsion but it's limited to only unbraced ones. I'm trying to see if there's a way to transform those results into one where there is point bracing.

 

[le99]

Have you tried 3D software?

 

[human909]

I understand this part, but I guess my question or issue is that I'd like to try to avoid reinventing the wheel (as you may know, AISC's Design Guide 9 is very long-winded and doesn't cover this scenario). I have software that is capable of designing members in torsion but it's limited to only unbraced ones. I'm trying to see if there's a way to transform those results into one where there is point bracing.

You wouldn't be reinventing the wheel. You'd be basic doing engineering.

le99 has already answered your question. Just design the beam for the lengths between the braces using the suitably calculated loads. Breaking up a structure or members into smaller parts for analysis is pretty much engineering 101.