Section 18.9.3.2 Midspan Two Way Minimum Reinforcement

For a cantilever span (as determined by the declaration of supports in the design strip segment), this criterion is ignored if the section location is inside of L/3 of the support.
For a regular span (as determined by the declaration of supports in the design strip segment), this criterion is ignored if the section location closer than L/6 from a support.
For a span with no supports (as determined by the declaration of supports in the design strip segment), this criterion is always applied.
See "Minimum Reinforcement" above for details regarding which slab/beam face (top or bottom) that the reinforcement will have the reinforcement added.
For strict adherence to ACI 318-99 this criterion should only be used for two-way slabs of uniform thickness ( RAM Concept uses it for all slabs declared as "two-way"; section 18.9.2 should be used for two-way slabs that do not have a uniform thickness. Under ACI 318-02 and IBC 2000 it is acceptable to use this criterion for all two-way slabs.)
Gross-section, linear-elastic stress calculations are used.
For sections with multiple concrete strengths, the minimum concrete strength is used to determine the limiting stress.
For sections with multiple concrete strengths, approximate extreme fiber stresses and centroid stresses are calculated and reported.
If $2 \sqrt{{f^{'}}_{c}}$ is exceeded the entire tensile load, N_c, is taken by bonded reinforcement.
User defined reinforcement on the appropriate face and bonded post-tensioning that is in the tension zone is counted toward the requirement. Vector components are taken of reinforcement and bonded post-tensioning that are not orthogonal to the cross section. Usable bonded tendon stresses are limited to the minimum of (f_py-f_se), (0.5 f_py) and 30 ksi.
Reinforcing bar stresses are limited to the minimum of (0.5 f_py) and 30 ksi.
The reinforcement is only provided where stresses exceed $2 \sqrt{{f^{'}}_{c}}$ , the minimum length requirements of 18.9.4.1 are not considered.
No check is made to ensure that the structure is post-tensioned.