Does AISC 13th Manual still allow 10% negative moment reduction?

[StructLin]

We usually reduce 10% negative moment in continuous W shape beam in our past design projects, which is allowed per LRFD Section A5.1. Now our company is going to change to use AISC 13th. I am not sure if it is still allowed to have this 10% reduction in negative moment. I can not find the same section in AISC 13th. Is it still allowed to have 10% reduction in AISC 13th.?


Thank you for your clarifications on this issue.

 

[frv]

Since I graduated after the 13th edition came out, I am unfamiliar with any other version.

Would you be referring to plastic design?

If so, Appendix 1 would be applicable.

Note that your sections must be compact to take advantage of plastic design.

 

[WillisV]

Yes - Appendix 1: Inelastic Analysis and Design: Section 1.3 "Moment Redistribution"

 

[Bagman2524]

The allowed 10% reduction comes from section F1.1 (pg 5-45) of ASD 9th edition. The moment design methodology is completely changed and is covered in chapter F in the 13th edition. Member design is based on plastic analysis with checks required for Lateral Torsional Buckling and other provisions depending on the type of section being used. I don't see anywhere where the 10% reduction is allowed. In section F1, at the bottom of page 16.1-46, there is a statement that available flexural strength >= maximum required moment causing compression in the flange being considered.