Section 10.3.3 Ductility (Non prestressed)

The strain distribution used in section 10.2 calculations is used (see Section 10.2 Factored Moment Resistance (Non prestressed) for details).
The neutral axis depth is limited to:
(0.75) × (0.003 /(0.003 + εy)) × d
where
εy
=
maximum reinforcement yield strain of all reinforcement in the cross section in tension
d
=
maximum depth of all tensile reinforcement in section (excluding PT)
Due to very large bar covers or other unusual conditions, the "compression" bar will be considered when determining "d" if the "compression" bar is in tension.
For details on how the neutral axis depth limit is related to the code criterion, see "Unified Design Recommendations for Reinforced...." by Antoine Naaman in ACI Structural Journal, pp 200-210, Vol 89, no.2, April-March 1992

εy	=	maximum reinforcement yield strain of all reinforcement in the cross section in tension
d	=	maximum depth of all tensile reinforcement in section (excluding PT)