"ductile failure" of anchor bolts

[broncosfan]

I am designing a base plate of a special concentrically based frame. I understand that it is preferable to maintain a ductile failure mode. Does this just mean that the strength of the concrete embedment needs to be greater that the steel strength of the anchor bolts? Currently, I have 1 3/8" A36 anchor bolts with 30" embed. The design tensile strength of 4 bolts is 257k. The design breakout strength of the 4 bolt group is 279k. The amplified seismic uplift is 176k. So 279k is greater than 257k and the design is "ductile." Is this correct? Do I need to maintain a certain factor of safety for ductility? Thanks.

 

[civilperson]

No, you got it correct. The steel will yield prior to concrete breakout.