ACI 318-08 Section 7.12.2

[ozcansam]

Dear Colleagues,

In ACI Section 7.12.2, states that ;

"Area of shrinkage and temperature
reinforcement shall provide at least the following ratios
of reinforcement area to gross concrete area, but not
less than 0.0014:"

Continuation ;

Slabs where Grade 60
deformed bars or welded wire
reinforcement are used...................................0.0018

Does anyone have any idea aboout that mentioned rebar ratios covers both two layer reinforcement amount or only one layer reinforcement amount at top or down?

P.S. : R7.12.2 — The amounts specified for deformed bars and
welded wire reinforcement are empirical but have been used
satisfactorily for many years. The area of reinforcement
given by 7.12.2.1 may be distributed near the top or bottom
of the slab, or may be allocated between the two faces of the
slab as deemed appropriate for specific conditions. Splices
and end anchorages of shrinkage and temperature reinforcement
are to be designed for the full specified yield strength
in accordance with 12.1, 12.15, 12.18, and 12.19.

 

[Nonlinearer]

These are gross area ratios but one directional which is at right angle to the main reinforcement and may be distributed near top and/or bottom of slabs as appropriate.

IR

 

[DST148]

Try thread507-251751. There is a lively discussion on shrinkage & temperature reinforcement.