Required length for column anchors

1. When  piers (concrete columns) are used, concrete breakout capacity alone cannot transfer the significant level of tensile forces from the steel column to the concrete base (due to the small dimensions of the pier cross-section).
2. In these instances, steel reinforcement in the concrete is used to carry the force from the anchor rods. 
3. The reinforcement must be sized and developed for the required tensile strength of the anchor rods.
4. The anchor rod embedment lengths are determined from the  required  development  length  of  the  spliced  reinforcement. 
5. Hooks or bends can be added to the reinforcing steel to minimize development length in the breakout cone. 
6. Anchor rod embedment length equals the top cover to reinforcing (i.e. the distance from reinforcement to top of concrete), plus Ld  (or Ldh  if hooked) plus 0.75 times g (where g is the distance from the anchor to the reinforcement, both axially). 
7. The minimum length of the anchor is 17 times the rod diameter.