Steel Seismic Moment Connection

[haynewp]

I am just looking for a quick verification on moment connections for steel in seismic design category C with R=3 (steel not detailed for seismic). I believe that you are still allowed to show end reactions of moment frame beams and have the steel detailer design the connections for these moments only, and not for the full capacity of the beam. I know the AISC seismic provisions have a lot of minimum connection requirements for moment frames in order to develop the required energy dissipation, but I am only designing for R=3 so I don't think I have to develop the full capacity of the beam by way of the connection. (Yielding in the connection is allowed in order to warrant the R=3, therefore the connection can still be designed for the moments from an elastic analysis derived from R=3 even if the rest of the system could deliver a larger force to the connection).

 

[prsconsultant]

haynewp:

Your assumptions are correct. When you are using an R=3, your seismic design forces are high (compared to an SMF system with R=8). By using R=3, you are required to design the connections only for the member design forces not the full expected strength of the member. If you have access to AISC seismic design handbook, there are examples showing OMF connection design for R=3.

 

[haynewp]

thanks-