R value for drift calcs

[EBF]

I am working on a bridge. The framing in the short direction is a steel moment frame. This sits on a concrete girder and concrete pier (forming a T on which the moment frame sits) at each end. I was using and R value of 2.2 per 1997 UBC for cantilevered column structures. Can I use this same value when calculating the inelastic displacement, Dm = 0.7*R*Ds? or do I need to use the R value for a steel moment frame, R = 8.5?

 

[Taro]

Use the same R factor you used to calculate your forces.