Regarding Bracing for lateral torsional Buckling 1

[kaffy]

Good Morning Fellow Engineers,

(File attached)

For calculating the lateral-torsional buckling bracing, AISC Appendix 6 specifies minimum requirements for both flexural strength about the longitudinal axis and flexural stiffness.
- Yura provides the formulation for calculating the stiffness values for diaphragms & certain cross frame. For diaphragms, I can calculate the flexural strength (sigma*section modulus). But what about cross frame? How do we calculate the flexural strength of those cross frames?
- Given the field requirements, I need to use chevron bracing, as shown in the attachment, which illustrates the framework and my planned attachment method to the stiffener. for those custom frameworks, how do we calculate the flexural stiffness & strength?

 

[lexpatrie]

Include the image in line, please (use the camera icon with a jpeg).

 

[KootK]

The relevant AISC provisions are really geared toward an end result that creates effective rotational springs connecting the twin beams. In general, your strategy will be to confirm that your chevron frames can function as those springs. So figure out the criteria and then do some modelling / math to prove that your frames are able to resist rotation with the requisite amount of stiffness and strength. Unit load investigations etc.