Development lengths are the same for compression and tension.

A rectangular beam has a cross section of b = 16 in., h = 22 in., and d = 19.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 3,700 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 casting-position modification factor, ψt, for a rectangular beam with b = 16 in. and d = 24 in., three epoxy-coated No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 10 in. along the span. Assume 6,000-psi lightweight concrete and a clear cover of 1.75 in.

A rectangular beam with cross section b = 16 in., h = 22 in., and d = 19.5 in. supports a total factored uniform load of 3.10 kips/ft, including its own dead load. The beam is simply supported with a 21-ft span. It is reinforced with five No. 8 Grade 60 bars, three 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 6,000 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 five bars is φMn = 320.8 kip-ft, and the strength of the remaining two bars is φMn = 134.5 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

A smooth bar embedded in concrete develops bond by _______ between the concrete and the bar and by a small amount of _______.

The ACI Code uses the concept of development length instead of _______, because the actual bond stress varies along the length of a reinforcing bar.

When large amounts of steel are to be used, they can be bundled together. This decreases the required development length of each bar.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 17 in. and d = 24 in., five galvanized No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 6,000-psi lightweight concrete and a clear cover of 1.5 in.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 17 in. and d = 20 in., five galvanized No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 40 stirrups located every 6 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.5 in.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 16 in. and d = 21 in., three epoxy-coated No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 40 stirrups located every 12 in. along the span. Assume 5,000-psi lightweight concrete and a clear cover of 1.5 in.