width-to-thickness ratio requirement for highly ductile members (Table D1.1 of seismic provision)

[compe_ad]

Hi all! Lets say I have a beam element (assume similar to reduced beam section) which will be under compression so it has to meet table D1.1 for high ductile member. I am thinking since whole member will be in compression I need to satisfy this requirement at both section cut A and B (see fig). Obviously, it satisfies at the reduced section (region where inelasticity will occur) and it doesn't satisfy at other section (elastic region). Is this okay or does this requirement has to satisfy throughout the length? Please provide me your suggestion and references if any.

 

[JoshPlumSE]

In AISC 358-16, the chapter on Reduced Beam Sections (chapter 5) says:

When determining the width-to-thickness ratio of the flange, the value of bf shall not be taken as less than the flange width at the end of the center 2/3 of the reduced section provided that gravity loads do not shift the location of the plastic hinge a significant distance from the center of the reduced beam section.

So, the code definitely has a "liberalization" of that element slenderness requirement at the reduced section. But, it is a minor reduction.