Strength Limit States for Local Buckling 1

[DJYork]

I attended a seminar awhile back, and the most interesting thing was the subject of compact sections.
- Most W-sections are always compact
- Only one W-section has a chance to be non-compact for Fy=36ksi -- W6x15
- Only seven W-sections have a chance to be non-compact for Fy=50ksi -- W6x15, W8x10, W10x12, W12x65, W14x90, W14x99, W40x174 --- So if you do not use these members you do not need to check for compact sections, and if you do they are 95%+ of the time will be compact.
- All C-sections and MC-sections are compact for Fy=36ksi and Fy=50ksi

FYI

 

[Taro]

Except if you are resisting seismic forces. Then the compactness limits are more stringent.

 

[DJYork]

I personally have not calced every possible scenerio for the members, but for all cases (per AISC seminar) the above should hold true.

 

[henri2]

Taro, are you referring here to the requirements for compactness limits in AISC Seismic Provisions (Table I-8-1)versus LFRD Design Spec (Table B5.1)?

 

[Taro]

Yes, if you are using a response modification factor greater than 3, you need to use more compact sections to achieve the ductility.