Effective depth of section (concrete beam: ACI 318)
For the design of the longitudinal tension reinforcement, the effective depth of a section, d is defined as the distance from the extreme concrete fiber in compression to the center of gravity of the longitudinal tension reinforcement.
For the design of the longitudinal compression reinforcement, the effective depth in compression, d2 is defined as the distance from the extreme fiber in compression to the center of gravity of the longitudinal compression reinforcement.
