Custom plate washer to increase Appendix D capacity

[precast78]

On appendix D, the A_NC is calculated from the center of the bolt. If I add a thick custom washer, is there a way to increase this number? I feel like my A_NC should be higher? Does Appendix D cover this anywhere?

 

[Lion06]

I only have my ACI 318-05 at home with me. I'm almost certain that 318-08 allows you to calculate Anc starting from the edge of your plate washer, not the center. I've never used the provision, but I'm almost certain it's there.

 

[mike20793]

I've done this when I needed a ductile failure of the anchor rods. Just make sure the plate can handle the uplift load in bending, but that shouldn't be too difficult to achieve.

 

[BUGGAR]

You can use a little tiny washer if you put it and the head of the anchor bolt at the bottom of the footing and calling it a through-bolt, which isn't covered by App D.
You will have to excavate a pocket around the head of the anchor to provide adequate concrete corrosion cover. But this way, you can avoid App D altogether.