SCBF Beams - Highly Ductile or Moderately Ductile

[d.krausz]

Hello!
I am studying for the SE exam, and noticed a new change in the newest (blue) seismic manual; In the table at the front, it now lists SCBF beams as highly ductile members, where they used to be moderately ductile. This is also reflected in the F2.5a Basic Requirements section in the AISC 341 chapter. Can everyone confirm this is correct?

**note, in the blue seismic manual, there is discrepancy within examples, on p5-150 and p5-158 one says moderately ductile, the other says highly ductile. In AISC 341 section, p9.1-66, it says beams are highly ductile, but in section F2.4b (b) is refer to beam bracing for Chevron type braces as moderately ductile.

Thanks!
Dorian

 

[psustruct]

I believe the changes are due to extensive testing and field studies. This article might spell it out, if anyone has access to it:
https://ascelibrary.org/doi/pdf/10.1061/9780784481325.022

As for the difference between the two differnet requirements, there are correctly printed. Page 5-150 is for BRACING requirements. Page 5-158 is for Width-to-Thickness requirements. This is my interpretation.

Back to your question about if it is correct, I may send a question to AISC to be sure. Especially since Table 1-2 does not differentiate between the two requirements. But the notes for Table 1-3 on page 1-30 elude that Table 1-2 is for width-to-thickness requirements.......

Some other significant changes are Table A3.1 and Table D1.1. And the NEW classification of Multi-Tier for OCBF and SCBF.

Terry