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.

A hooked bar can resist pull-out more effectively if _______.

Determine the casting-position modification factor, ψt, for a rectangular beam with b = 16 in. and d = 20 in., three galvanized No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 40 stirrups located every 10 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 2 in.

Determine the epoxy modification factor, ψe, 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. 3 Grade 60 stirrups located every 10 in. along the span. Assume 8,000-psi normal-weight concrete and a clear cover of 1.5 in.

A rectangular beam has a cross section of b = 14 in., h = 24 in., and d = 21.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 9,400 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the cracked moment of inertia, Icr. The neutral axis location of the cracked beam (measured from the top of the beam) is 4.1442 in.

A rectangular beam has a cross section of b = 16 in., h = 26 in., and d = 23.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 2,500 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

Heads can be attached to one or both ends of a bar by internal threads on the head mating to the bar, welding or forging onto the bar, or by a separate nut used to secure the head onto the 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 = 22 in., four galvanized No. 8 Grade 60 bars placed in the top of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 7,000-psi normal-weight concrete and a clear cover of 1.75 in.

Concrete can crack due to imposed deformations, such as differential settlement, shrinkage, and temperature differentials.

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 = 22 in., four galvanized No. 8 Grade 60 bars placed in the top of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 7,000-psi normal-weight concrete and a clear cover of 1.75 in.