Hooks can be attached to one or both ends of a bar by internal threads on the hook mating to the bar, welding or forging onto the bar, or by a separate nut used to secure the hook onto the bar.

The stress in reinforcing steel is _______ at cracks, while the concrete stress is _______ at cracks.

For economy, some of the bars can be terminated or cutoff where they are no longer needed.

A rectangular beam with cross section b = 14 in., h = 22 in., and d = 19.5 in. supports a total factored uniform load of 1.70 kips/ft, including its own dead load. The beam is simply supported with a 18-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 7,200 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. The strength of the four bars is φMn = 106.4 kip-ft, and the strength of the remaining two bars is φMn = 53.8 kip-ft. If the distance from the support to the theoretical cutoff point is 4.792 ft, determine the distance from the support to the actual cutoff point (i.e. use ACI 318-14 Section 9.7.3.3).

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 22 in., four epoxy-coated No. 6 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 40 stirrups located every 12 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.75 in.

The development length for a hooked bar is generally shorter than that for a headed bar.

Hooked anchorages provide additional anchorage when there is insufficient straight length available to develop a bar.

A rectangular beam with cross section b = 16 in., h = 20 in., and d = 17.5 in. supports a total factored uniform load of 1.00 kips/ft, including its own dead load. The beam is simply supported with a 21-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 6,300 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. The strength of the four bars is φMn = 95.23 kip-ft, and the strength of the remaining two bars is φMn = 48.22 kip-ft. If the distance from the support to the theoretical cutoff point is 6.784 ft, determine the distance from the support to the actual cutoff point (i.e. use ACI 318-14 Section 9.7.3.3).

A rectangular beam with cross section b = 16 in., h = 28 in., and d = 25.5 in. supports a total factored uniform load of 1.40 kips/ft, including its own dead load. The beam is simply supported with a 24-ft span. It is reinforced with five No. 5 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 5,400 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 = 173.4 kip-ft, and the strength of the remaining two bars is φMn = 70.44 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

Map cracking can be controlled by limiting the heat rise due to the heat of hydration and the rate of cooling, or both; by placing the wall in short lengths; or by reinforcement considerably in excess of normal shrinkage reinforcement.