Question regarding Horizontal Reinforcement for Walls greater than 10 inches for ACI 318-19

[oengineer]

Section 11.7.2.3 of ACI 318-19 states the following:

It appears to be worded a little different from the ACI 318-14 version:

Would it be safe & acceptable to interpret that for ACI 318-19 code when designing walls thicker than 10 inches, we distribute the required horizontal reinforcing evenly between the inside and the outside faces?

Comments/suggestions are appreciated.

 

[oengineer]

I would appear that distributing the required horizontal reinforcing evenly between the inside and the outside faces should still be acceptable for ACI 318-19, but I am open to any other thoughts.

 

[hardbutmild]

I am confused. What would be the alternative (other than placing it in one layer which is obviously not allowed)?

Horizontal reinforcement in a wall transfers in-plane shear so it should be evenly distributed between the two faces.

 

[hokie66]

If the wall is spanning horizontally, you may need more reinforcement in one face than the other. Otherwise, the horizontal bars are mostly for shrinkage, and should be evenly distributed.

 

[oengineer]

I am confused. What would be the alternative (other than placing it in one layer which is obviously not allowed)?

One could place the calculated horizontal reinforming at the full value in both faces of the wall instead of evenly distributing them.

 

[HTURKAK]

My interpretation is , this clause is applicable for non seismic design of the walls as vertical and lateral force-resisting members having thickness greater than 10 in. the distributed reinforcement shall be placed in at least two layers, one near each face.The exceptions are single story basement walls and cantilever retaining walls.

That is , single story basement walls and cantilever retaining walls still can have single layer reinf.

The old code ACI 318-14 gives chance to use different amount of steel at exterior and interior surface.
One can easily see that the exterior steel amount could be more than interior surface steel which is applicable at exterior walls of a structure for temperature reinf.
In past , i have always preferred symmetrical reinf.

He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[oengineer]

I just found a chart in the CRSI Design Guide for ACI 318-19. Here are some recommended transverse (horizontal) reinforcement for wall thickness:

Both of these charts from the CRSI Design Guide support the evenly distribution of reinforcement between both faces for horizontal reinforcement.

 

[hokie66]

Those charts provide .0020 and .0025Ag reinforcement. Not nearly enough for shrinkage crack control in heavily restrained walls.