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Smooth bars are generally not used as longitudinal reinforcement because _______.

A simply-supported beam has a 1 kip/ft uniformly-distributed load over the entire 10-ft span. What is the magnitude of the shear force at midspan?

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 20 in. and No. 3 stirrups. This beam has three No. 8 bars as longitudinal reinforcement. The clear cover is 1.8 in.

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. 5 Grade 60 bars. The concrete strength is 7,600 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.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 23 in., three epoxy-coated No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 40 stirrups located every 6 in. along the span. Assume 4,000-psi lightweight 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 two No. 7 Grade 60 bars. The concrete strength is 7,300 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.

Smooth bars are generally used for longitudinal reinforcement.

When tension is applied to a smooth reinforcing bar, its diameter is increased. Due to the increase in diameter, the adhesion and friction bonds that originally held it in place are quickly lost.

A rectangular beam with cross section b = 16 in., h = 28 in., and d = 25.5 in. supports a total factored uniform load of 3.50 kips/ft, including its own dead load. The beam is simply supported with a 23-ft span. It is reinforced with four No. 8 Grade 60 bars, two of which are cutoff between midspan and the support and two of which extend 10 in. past the centers of the supports. The concrete strength is 3,600 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. The strength of the four bars is φMn = 335.1 kip-ft, and the strength of the remaining two bars is φMn = 174.4 kip-ft. If the distance from the support to the theoretical cutoff point is 5.791 ft, determine the distance from the support to the actual cutoff point (i.e. use ACI 318-14 Section 9.7.3.3).

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 = 23 in., four galvanized No. 8 Grade 60 bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 10 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.75 in.