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Compute φVn for the cross section shown. Assume f’c = 7,000 psi, fyt = 40,000 psi, d = 27 in., w = 19.5 in., t = 5 in., and that there are four No. 6 longitudinal tension bars and No. 3 stirrups at 9 in. o.c.

In reinforced concrete beams, the flexural tensile forces are resisted by the concrete, while the flexural compressive forces are provided by the reinforcement. Bond stresses must be present for the reinforcement bar to be in equilibrium. Otherwise, the bar will pull out of the concrete causing the beam to fail.

Shear failures in concrete tend to _______.

A rectangular beam has a cross section of b = 16 in., h = 30 in., and d = 27.5 in. It is reinforced with four No. 5 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 green, dashed lines in the following image represent the _______.

Determine the epoxy modification factor, ψe, for a rectangular beam with b = 18 in. and d = 22 in., four galvanized No. 6 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 12 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.75 in.

Determine the casting-position modification factor, ψt, for a rectangular beam with b = 18 in. and d = 21 in., five uncoated No. 6 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 8 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 2 in.

Assuming Vs does not exceed 4sqrt(f’c)bwd, the maximum spacing for vertical stirrups in the following beam is _____. Let d = 47 in., w = 37.5 in., and t = 6 in. There are five No. 8 longitudinal tension bars and No. 3 stirrups at 8 in. o.c.

For a beam with stirrup hooks, the free end of the bar must extend at least _____ from the hook. Assume b1 = 35 in., b2 = 15 in., d1 = 6 in., d2 = 27 in., and that there are three No. 6 longitudinal tension bars and No. 4 stirrups at 9 in. o.c. The stirrup hooks are 90°.

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