A concrete slab-on-ground cast monolithically with the footing shall be permitted to locate which reinforcement arrangement in the middle third of the footing as an alternative to placement at the top and bottom?

A concrete slab-on-ground cast monolithically with the footing shall be permitted to locate which reinforcement arrangement in the middle third of the footing as an alternative to placement at the top and bottom?

• A. 2 number 5 bars, one on top and one on bottom footing
• B. 2 number 4 bars, tied together at the top of the footing
• C. 1 number 5 or 2 number 4 bars in the middle third of the footing
• D. 1 number 5 bar in the middle of the footing

Answer: (C)

When a slab-on-ground is cast monolithically with its footing, the bending and cracking tendencies in the footing are better addressed by placing the tensile reinforcement in the interior portion of the depth rather than strictly at the extreme top or bottom fibers. Placing reinforcement in the middle third provides ample tensile resistance while keeping bars away from the surface that contacts soil and moisture, which can be advantageous for durability and constructability. The permitted arrangement—one bar of size #5 or two bars of size #4 located in the middle third—gives enough steel area to carry the tensile forces without crowding the surface or complicating placement. Using bars in the middle third simplifies detailing and construction and aligns with how the footing and slab interact with the supporting soil. So, the best answer is to place either a single #5 bar or two #4 bars in the middle third of the footing.

When a slab-on-ground is cast monolithically with its footing, the bending and cracking tendencies in the footing are better addressed by placing the tensile reinforcement in the interior portion of the depth rather than strictly at the extreme top or bottom fibers. Placing reinforcement in the middle third provides ample tensile resistance while keeping bars away from the surface that contacts soil and moisture, which can be advantageous for durability and constructability.

The permitted arrangement—one bar of size #5 or two bars of size #4 located in the middle third—gives enough steel area to carry the tensile forces without crowding the surface or complicating placement. Using bars in the middle third simplifies detailing and construction and aligns with how the footing and slab interact with the supporting soil.

So, the best answer is to place either a single #5 bar or two #4 bars in the middle third of the footing.