If you are a detailer creating shop drawings for a parking garage or a high-seismic zone building, clause 4.2 contains the non-negotiable geometry that prevents buckling of main reinforcement.
Details and Detailing of Concrete Reinforcement (ACI 315-99) Aci 315 08 42.pdf
this manual is the "language" through which structural engineers communicate with the people actually bending and placing steel on-site. If you are a detailer creating shop drawings