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.

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 lightweight modification factor, λ, for a rectangular beam with b = 16 in. and d = 22 in., four galvanized No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 12 in. along the span. Assume 5,000-psi normal-weight concrete and a clear cover of 1.75 in.

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.

What type of reinforcement is frequently used in bridge decks and parking garages to reduce corrosion problems?

If the bond between concrete and steel in a beam disappears, the steel will not pull out of the concrete.

A rectangular beam with cross section b = 16 in., h = 28 in., and d = 25.5 in. supports a total factored uniform load of 2.80 kips/ft, including its own dead load. The beam is simply supported with a 22-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 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 = 267.5 kip-ft, and the strength of the remaining two bars is φMn = 135.7 kip-ft. If the distance from the support to the theoretical cutoff point is 6.094 ft, determine the distance from the support to the actual cutoff point (i.e. use ACI 318-14 Section 9.7.3.3).

Which of the following should NOT be used to determine the location of bar cutoff points?

In a lapped splice, the force in one bar is transferred to the concrete, which transfers it to the adjacent bar.