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

The stress in the reinforcement goes to zero at a crack.

A rectangular beam with cross section b = 16 in., h = 20 in., and d = 17.5 in. supports a total factored uniform load of 2.00 kips/ft, including its own dead load. The beam is simply supported with a 21-ft span. It is reinforced with four No. 7 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 3,000 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 four bars is φMn = 169.9 kip-ft, and the strength of the remaining two bars is φMn = 89.74 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 rectangular beam has a cross section of b = 16 in., h = 26 in., and d = 23.5 in. It is reinforced with five No. 7 Grade 60 bars. The concrete strength is 5,200 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. Determine the strength φMn for this beam.

The development length for a hooked bar is generally longer than that for a headed 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., three epoxy-coated No. 6 Grade 60 bars placed in the bottom of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 7,000-psi lightweight concrete and a clear cover of 1.75 in.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 16 in. and d = 23 in., five galvanized No. 8 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 6,000-psi normal-weight concrete and a clear cover of 2 in.

Determine the size modification factor, ψs, for a rectangular beam with b = 16 in. and d = 23 in., three galvanized No. 6 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 12 in. along the span. Assume 8,000-psi normal-weight concrete and a clear cover of 2 in.

A simply supported beam with dimensions of b = 16 in., h = 26 in., d = 23.5 in., and L = 18 ft supports a uniform service (unfactored) dead load of 2.133333 kips/ft including its own self weight plus a uniform service (unfactored) live load of 1.0 kips/ft. The concrete is normal-weight concrete. The beam is reinforced with 3 No. 5 bars. The concrete strength is 3,100 psi, and the yield strength of the reinforcement is 60,000 psi. Determine the maximum applied bending moment due to the combined service loads (dead plus live), Ma.      

A large stress concentration, possibly leading to large inclined cracks, happens when a tension bar is cutoff at a location of low shear force.