Minimum Reinforcing

[miecz]

The minimum reinforcing for slabs is governed by ACI 318, Article 7.12, as referenced by 10.5.4.

Turning to ACI 350, the same is true, only ACI 350 clarifies this to apply to tank walls, as well as horizontal slabs.

Both codes read "the minimum area of tensile reinforcement in the direction of the span as required by 7.12."

The commentary, R10.5.4 restates this, but leaves out the word "tensile".

So which is it? Is the minimum tensile reinforcement limited to the ratios given in 7.12, or is the minimum total (both faces) reinforcement (in, say, the horizontal direction) limited to the ratios given in 7.12?

 

[civilperson]

The minimum reinforcement is given in ACI 10.5.1, 10.5.3, and 10.5.4, (which is 7.12). This applies to either top layer for negative moment or bottom layer for positive or both if both positive and negative moments can occur at this location. Slabs are further required to have 7.12 minimums in both directions and have reinforcement in both top and bottom next to spandrel beams sufficient to resist the maximum positive moment.