For a monolithic slab-on-ground, which reinforcement arrangement is permitted in the middle third of the footing?

For a monolithic slab-on-ground, which reinforcement arrangement is permitted in the middle third of the footing?

• A. 2 number 5 bars on top and bottom
• B. 1 number 6 bar in middle
• C. 1 number 5 or 2 number 4 bars in the middle third
• D. 2 number 4 bars on outside

Answer: (C)

In a monolithic slab-on-ground footing, the middle third is where the bending moment is managed with a practical, economical amount of steel. The permitted reinforcement pattern there is one No.5 bar or two No.4 bars in the middle third because they provide roughly the same tensile steel area needed to control cracks and carry stresses without overdoing the reinforcement. This keeps construction simpler and ensures adequate performance without unnecessary congestion or cost. The other options either involve heavier reinforcement in regions that don’t require it or use a single bar size that isn’t the standard, given the typical moment distribution in the middle third.

In a monolithic slab-on-ground footing, the middle third is where the bending moment is managed with a practical, economical amount of steel. The permitted reinforcement pattern there is one No.5 bar or two No.4 bars in the middle third because they provide roughly the same tensile steel area needed to control cracks and carry stresses without overdoing the reinforcement. This keeps construction simpler and ensures adequate performance without unnecessary congestion or cost.

The other options either involve heavier reinforcement in regions that don’t require it or use a single bar size that isn’t the standard, given the typical moment distribution in the middle third.