An elastic calculation gives a good estimate of the concrete and steel stresses at working loads.

Compute the maximum bar spacing, s, to control for cracks in a one-way slab with 2.5 in. of clear cover and f​y​ = 54 ksi.

Creep decreases the stress in the tension steel.

At service loads, the reinforcing steel is in the elastic range of behavior.

A simply supported beam with dimensions of b = 18 in., h = 22 in., d = 19.5 in., and L = 19 ft supports a uniform service (unfactored) dead load of 1.7125 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.1 kips/ft. The beam is reinforced with two No. 6 Grade 60 bars. The concrete strength is 2,800 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the effective moment of inertia, Ie.The cracked moment Mcr = 48.02 kip-ft, and the maximum applied bending moment due to the combined service loads (dead plus live) Ma = 126.9 kip-ft. The neutral axis location of the cracked beam (measured from the top of the beam) is 3.8373 in.

A simply supported beam with dimensions of b = 16 in., h = 26 in., d = 23.5 in., and L = 21 ft supports a uniform service (unfactored) dead load of 1.533333 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 4 No. 5 bars. The concrete strength is 6,700 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 rectangular beam has a cross section of b = 18 in., h = 26 in., and d = 23.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 6,700 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

A rectangular beam has a cross section of b = 18 in., h = 26 in., and d = 23.5 in. It is reinforced with two No. 7 Grade 60 bars. The concrete strength is 8,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

Reinforced concrete buildings are usually subject to vibration problems.

A simply supported beam with dimensions of b = 14 in., h = 24 in., d = 21.5 in., and L = 21 ft supports a uniform service (unfactored) dead load of 1.35 kips/ft including its own self weight plus a uniform service (unfactored) live load of 0.8 kips/ft. The beam is reinforced with four No. 8 Grade 60 bars. The concrete strength is 8,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Using the effective moment of inertia, determine the immediate mid-span deflection of the beam due to the combined service loads (dead plus live).The effective moment of inertia Ie = 8,139.1 in.4.