At what ratio are the deflections of spans typically visible, where L is the span of the beam?

A rectangular beam has a cross section of b = 14 in., h = 24 in., and d = 21.5 in. It is reinforced with four No. 5 Grade 60 bars. The concrete strength is 2,800 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 5.2594 in.

Misalignment of the reinforcement cannot cause eccentricities in columns.

Cracks in a member lower the member’s moment of inertia, thereby decreasing the member’s stiffness.

A rectangular beam has a cross section of b = 16 in., h = 28 in., and d = 25.5 in. It is reinforced with three No. 8 Grade 60 bars. The concrete strength is 8,200 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 = 19 ft supports a uniform service (unfactored) dead load of 2.0625 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.3 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 2 No. 8 bars. The concrete strength is 3,100 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.      

Compute the maximum bar spacing, s, to control for cracks in a one-way slab with 2 in. of clear cover and f​y​ = 66 ksi.

A rectangular beam has a cross section of b = 18 in., h = 26 in., and d = 23.5 in. It is reinforced with four No. 6 Grade 60 bars. The concrete strength is 5,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

A beam is singly reinforced with the reinforcement in two rows. The bottom row contains 8 No. 6 bars at a depth of 14 in. The top row contains 5 No. 5 bars at a depth of 8 in. Determine the effective (centroidal) depth, d, of the steel.

A rectangular beam has a cross section of b = 16 in., h = 28 in., and d = 25.5 in. It is reinforced with three No. 7 Grade 60 bars. The concrete strength is 5,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.