Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 18 in. and No. 4 stirrups. This beam has three No. 8 bars as longitudinal reinforcement. The clear cover is 1.5 in.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 24 in., three uncoated No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 6 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.75 in.

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.

A rectangular beam with cross section b = 16 in., h = 24 in., and d = 21.5 in. supports a total factored uniform load of 1.20 kips/ft, including its own dead load. The beam is simply supported with a 22-ft span. It is reinforced with four No. 5 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 7,500 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 = 117.9 kip-ft, and the strength of the remaining two bars is φMn = 59.48 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

Compute φVn for the cross section shown. Assume f’c = 6,500 psi, fyt = 40,000 psi, b = 12 in., d = 25 in., and that there are four No. 6 longitudinal tension bars and No. 3 stirrups at 8 in. o.c.

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

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.

Bond stresses must be absent whenever the stress or force in a reinforcing bar changes from point to point along the length of the bar.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 23 in., three uncoated No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 8 in. along the span. Assume 4,000-psi normal-weight concrete and a clear cover of 1.75 in.

When large amounts of steel are to be used, they can be bundled together. This increases the effective perimeter of each bar.