A rectangular beam with cross section b = 16 in., h = 26 in., and d = 23.5 in. supports a total factored uniform load of 2.00 kips/ft, including its own dead load. The beam is simply supported with a 22-ft span. It is reinforced with five No. 6 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 3,900 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 = 220.3 kip-ft, and the strength of the remaining two bars is φMn = 91.09 kip-ft. If the distance from the support to the theoretical cutoff point is 5.531 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 casting-position modification factor, ψt, for…
Determine the casting-position modification factor, ψt, for a rectangular beam with b = 17 in. and d = 24 in., four epoxy-coated No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 8 in. along the span. Assume 6,000-psi lightweight concrete and a clear cover of 2 in.
Determine the epoxy modification factor, ψe, for a rectangul…
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.
The development length for a _______ bar generally will be s…
The development length for a _______ bar generally will be shorter than that for a _______ bar.
At cracks in reinforced concrete, the stress in the reinforc…
At cracks in reinforced concrete, the stress in the reinforcing steel is _______ and the stress in the concrete is _______.
Use ACI 318-14 Table 25.4.2.2 to determine the development l…
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 = 16 in. and d = 24 in., four epoxy-coated No. 8 Grade 60 bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 12 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.75 in.
Determine the casting-position modification factor, ψt, for…
Determine the casting-position modification factor, ψt, for a rectangular beam with b = 16 in. and d = 21 in., five epoxy-coated 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 6,000-psi lightweight concrete and a clear cover of 1.5 in.
Actual bond stresses vary from point to point between cracks…
Actual bond stresses vary from point to point between cracks.
Compute φVn for the cross section shown. Assume f’c = 6,500…
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.
Determine the casting-position modification factor, ψt, for…
Determine the casting-position modification factor, ψt, for a rectangular beam with b = 16 in. and d = 20 in., five galvanized No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 40 stirrups located every 10 in. along the span. Assume 5,000-psi normal-weight concrete and a clear cover of 1.5 in.