Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 16 in. and No. 3 stirrups. This beam has five No. 8 bars as longitudinal reinforcement. The clear cover is 1.8 in.

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 = 23 in., four uncoated No. 8 Grade 60 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 normal-weight concrete and a clear cover of 1.75 in.

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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.

The fatigue strength of stirrups is less than that of longitudinal bars.

What λ value should be used for lightweight-aggregate concrete?

Larger diameter aggregate creates a rougher crack surface, allowing higher shear stresses to be transferred across cracks.

When large amounts of steel are to be used, they can be bundled together. This decreases the required development length of each bar.

Which is generally shorter?

Compute φVn for the cross section shown. Assume f’c = 4,000 psi, fyt = 60,000 psi, b = 15 in., d = 24 in., and that there are four No. 7 longitudinal tension bars and No. 5 stirrups at 6 in. o.c.