For parallel reinforcement in a horizontal layer, clear spacing is controlled automatically according to 25.2.
According to 25.2.3, for longitudinal reinforcement in columns, pedestals, struts, and boundary elements in walls, clear spacing between bars is controlled automatically according to 25.2.3
Symbols
dagg = Nominal maximum size of coarse aggregate, in.
db = Nominal diameter of bar, wire, or prestressing strand, in. 25.2 - Minimum spacing of reinforcement
According to ACI 318-19, for parallel reinforcement in a horizontal layer, clear spacing is controlled automatically at least the greatest of
1 in
db
(4/3)dagg
According to 25.2.3, for longitudinal reinforcement in columns, pedestals, struts, and boundary elements in walls, clear spacing between bars is controlled automatically at least the greatest of
1.5 in.
1.5db
(4/3)dagg