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When the steel ratio is large, flexural cracks extend higher into the beam and open wider.

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 22 in. and No. 3 stirrups. This beam has three No. 7 bars as longitudinal reinforcement. The clear cover is 2 in.

Determine the epoxy modification factor, ψe, for a rectangular beam with b = 18 in. and d = 21 in., five uncoated No. 6 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 6 in. along the span. Assume 4,000-psi normal-weight concrete and a clear cover of 1.75 in.

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Use ACI 318-14 Table 25.4.2.2 to determine the development length for the straight tension bars (no hooks) in a rectangular beam with b = 17 in. and d = 24 in., three uncoated No. 6 Grade 60 bars placed in the top of the beam, and No. 3 Grade 60 stirrups located every 12 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.5 in.

A 120-mm-long beam supports a load of P = 47 N at midspan. The cross section is rectangular with width b = 27 mm and height h = 60 mm. Determine the magnitude of the horizontal shear stress at the centroid of the cross section.

Epoxy-coated or galvanized reinforcement is used to reduce corrosion problems.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 18 in. and d = 23 in., five galvanized No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 60 stirrups located every 6 in. along the span. Assume 8,000-psi normal-weight concrete and a clear cover of 1.75 in.

A rectangular beam has a cross section of b = 14 in., h = 30 in., and d = 27.5 in. It is reinforced with four No. 7 Grade 60 bars. The concrete strength is 5,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups satisfying ACI 318-14 Sections 9.7.6.2.2 and 9.6.3.3. Determine the strength φMn for this beam.

When the force in a reinforcing bar changes from point to point along its length, there must be bond stresses between it and the concrete.