Section 18.9.3.2 Midspan Two Way Minimum Reinforcement
For span segment strips, this criteria is only applied when the span
ratio is in the middle one-third of the span.
For a span with no supports (as determined by the declaration of
supports in the design strip segment), this criterion is always applied.
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 is exceeded the entire tensile load, Nc, 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 (fpy –
fse), (0.5 fpy) and 30
ksi.
Reinforcing bar stresses are limited to the minimum of (0.5 fpy) and 30
ksi.
The reinforcement is only provided where stresses
exceed , the minimum length requirements of 18.9.4.1 are considered with code
span detailing requirements.
No check is made to ensure that the structure is post-tensioned.