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A rectangular beam has a cross section of b = 16 in., h = 30 in., and d = 27.5 in. It is reinforced with three No. 8 Grade 60 bars. The concrete strength is 7,900 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the cracked moment of inertia, Icr. The neutral axis location of the cracked beam (measured from the top of the beam) is 6.0334 in.

A simply supported beam with dimensions of b = 18 in., h = 24 in., d = 21.5 in., and L = 21 ft supports a uniform service (unfactored) dead load of 1.45 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.2 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 3 No. 8 bars. The concrete strength is 6,400 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.      

Reinforced concrete members usually crack under service loads.

A rectangular beam has a cross section of b = 14 in., h = 30 in., and d = 27.5 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.

The major strength limit states in reinforced concrete are caused by excessive deflections, excessive crack widths, and undesirable vibrations.

It’s relatively easy to estimate the natural frequency of a floor if its mass can be calculated.

Crack widths are a concern for several reasons. Which of the following is NOT one of these reasons?

The major serviceability limit states in reinforced concrete are caused by excessive deflections, excessive crack widths, and undesirable vibrations.

States at which the structure becomes unfit for its intended function are called limit states.

A simply supported beam with dimensions of b = 18 in., h = 22 in., d = 19.5 in., and L = 21 ft supports a uniform service (unfactored) dead load of 1.4125 kips/ft including its own self weight plus a uniform service (unfactored) live load of 0.8 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 2 No. 5 bars. The concrete strength is 9,100 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.