When a section cracks, its moment of inertia increases, leading to a decrease in the stiffness of the beam.

A rectangular beam has a cross section of b = 14 in., h = 26 in., and d = 23.5 in. It is reinforced with five No. 5 Grade 60 bars. The concrete strength is 8,800 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the transformed cross-sectional area of the bars, Ast.

People dancing can cause vibration problems in buildings.

A rectangular beam has a cross section of b = 14 in., h = 24 in., and d = 21.5 in. It is reinforced with five No. 6 Grade 60 bars. The concrete strength is 7,300 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the cracking moment, Mcr.

A simply supported beam with dimensions of b = 18 in., h = 30 in., d = 27.5 in., and L = 16 ft supports a uniform service (unfactored) dead load of 2.3625 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.5 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 4 No. 8 bars. The concrete strength is 6,100 psi, and the yield strength of the reinforcement is 60,000 psi. Determine the maximum applied bending moment due to the combined service loads (dead plus live), Ma.      

A simply supported beam with dimensions of b = 16 in., h = 28 in., d = 25.5 in., and L = 20 ft supports a uniform service (unfactored) dead load of 1.766667 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.0 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 5 No. 8 bars. The concrete strength is 3,400 psi, and the yield strength of the reinforcement is 60,000 psi. Determine the maximum applied bending moment due to the combined service loads (dead plus live), Ma.      

Columns with spirals generally exhibits less ductility than columns without spirals.

If the exterior frames of a building are exposed to atmospheric temperature changes and the interior is maintained at a constant temperature, a relative vertical deflection can occur between the interior and exterior columns.

Increasing the permeability of the concrete will limit or delay corrosion of the reinfocement.

The ACI Code defines 0.02 as the maximum usable compressive strain for reinforced concrete.