ductile failure of anchor bolts
 

"ductile failure" of anchor bolts
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.

no, you got it correct. the steel will yield prior to concrete breakout.