The sides of the main field of the slab must be reinforced with an ___ by ___ grid.

The sides of the main field of the slab must be reinforced with an ___ by ___ grid.

• A. 15 by 18
• B. 10 by 12
• C. 12 by 12
• D. 8 by 16

Answer: (A)

Edge reinforcement in a slab is all about tying the perimeter to the interior reinforcement to control cracks and keep the edge stiff under load. The sides of the main field are reinforced with a grid that runs in two directions along the edge, so the reinforcement evenly distributes stresses and prevents the boundary from acting as a weak point. Using a grid spaced 15 inches by 18 inches provides enough reinforcement along both directions to restrain shrinkage and bending at the edge, while not overdoing it. This spacing is a practical, commonly used balance that ensures the edge has adequate stiffness and crack control without unnecessary material. Spacings tighter than this would add cost without proportionate benefit, and looser spacings could fail to control edge cracking and movement, which is why this 15 by 18 inch grid is the preferred choice for this scenario.

Edge reinforcement in a slab is all about tying the perimeter to the interior reinforcement to control cracks and keep the edge stiff under load. The sides of the main field are reinforced with a grid that runs in two directions along the edge, so the reinforcement evenly distributes stresses and prevents the boundary from acting as a weak point. Using a grid spaced 15 inches by 18 inches provides enough reinforcement along both directions to restrain shrinkage and bending at the edge, while not overdoing it. This spacing is a practical, commonly used balance that ensures the edge has adequate stiffness and crack control without unnecessary material. Spacings tighter than this would add cost without proportionate benefit, and looser spacings could fail to control edge cracking and movement, which is why this 15 by 18 inch grid is the preferred choice for this scenario.