Flexure Yielding Limit State for a solid steel beam 1

[Soicey75]

I am designing a spread sheet for analysis of a solid steel rectangular section that is larger than Lb*d/t^2. I am using AISC 360-16 to attain the flexure capacity of the member but I can't find a condition where my rectangular sections meets in chapter F. I tried using section F.11 for square bars but the yielding state equation can only be applied to members with a Lb*d/t^2 is less than 0.08*E/Fy and my dimensions are larger. Where else in the specs or in other codes can I find functions to work with my beam ?

 

[E720]

I think that probably the reason for the limits on the plastic moment equation is that if you have a longer beam then it will not be governed by the plastic moment equation, but rather LTB. I think that it would be permissible to use the same plastic moment equation for beams with bigger length to depth ratios where LTB didnt apply, like for minor axis bending or for a square beam.

 

[Hokie93]

Is your L_bd/t² ratio greater than 0.08E/F_y? If so, then Eq. (F11-2) or Eq. (F11-3) are what you need. If L_bd/t² exceeds 0.08E/Fy, then LTB is applicable. Those equations are on the next page in the Specification (AISC 360-16).

 

[BAretired]

A lower Fy could be assumed such that the condition is satisfied.

BA