What is the average deadload of dry concrete, including reinforcement?

What is the average deadload of dry concrete, including reinforcement?

• A. 100 lbs/sq ft
• B. 125 lbs/sq ft
• C. 200 lbs/sq ft
• D. 150 lbs/sq ft

Answer: (D)

Dead load is the weight of materials that remain in place, expressed per unit area. For a concrete slab with reinforcement, the main contributors are the concrete itself and the steel in it. Concrete weighs about 150 pounds per cubic foot. To get pounds per square foot, multiply this unit weight by the slab thickness in feet. A typical slab’s concrete portion yields roughly 50–75 lbs/sq ft (depending on thickness), and the reinforcement adds a bit more. In many practice problems, a convenient, round value is used to represent dry concrete including reinforcement: about 150 lbs/sq ft. This provides a simple, conservative estimate when exact thickness and reinforcement details aren’t given. If you know the actual thickness and reinforcement layout, you can compute the exact dead load by applying the 150 lb/ft3 density times the thickness and adding the steel load per area.

Dead load is the weight of materials that remain in place, expressed per unit area. For a concrete slab with reinforcement, the main contributors are the concrete itself and the steel in it. Concrete weighs about 150 pounds per cubic foot. To get pounds per square foot, multiply this unit weight by the slab thickness in feet. A typical slab’s concrete portion yields roughly 50–75 lbs/sq ft (depending on thickness), and the reinforcement adds a bit more. In many practice problems, a convenient, round value is used to represent dry concrete including reinforcement: about 150 lbs/sq ft. This provides a simple, conservative estimate when exact thickness and reinforcement details aren’t given. If you know the actual thickness and reinforcement layout, you can compute the exact dead load by applying the 150 lb/ft3 density times the thickness and adding the steel load per area.