No of Anchor Bolt Along Width / Depth Edge
nbw and nbd are for side-face blowout check use.

* Side face blowout resistance only needs to compare with the
   sum of tensile force of anchor bolts close to an edge
   (Reference ACI 318-14  R17.4.4.2)
* nbw and nbd are the number of bolt along each edge. These two
   inputs are used to calculate the applicable portion of tensile
   force acting along each edge for side face blowout check use.
* nbw is the no of bolt along pedestal width edge (bc edge), one
   side only
.
* nbd is the no of bolt along pedestal depth edge (dc edge), one
   side only
.

ACI 318-14 R17.4.4.2