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Due to Poisson’s ratio, the diameter of the reinforcing bar decreases as it is loaded in tension and both the bond the adhesion and the friction between it and the concrete are lost.

Compute φVn for the cross section shown. Assume f’c = 4,000 psi, fyt = 40,000 psi, b = 11 in., d = 20 in., and that there are four No. 6 longitudinal tension bars and No. 5 stirrups at 10 in. o.c.

Inclined stirrups are an effective solution for resisting seismic loads.

If the depth of the beam varies, the compressive and tensile forces due to flexure will have vertical components.

Which of the following stirrup designs is not acceptable?

Smooth bars are generally not used as longitudinal reinforcement because _______.

A simply-supported beam has a 1 kip/ft uniformly-distributed load over the entire 10-ft span. What is the magnitude of the shear force at midspan?

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 20 in. and No. 3 stirrups. This beam has three No. 8 bars as longitudinal reinforcement. The clear cover is 1.8 in.

A rectangular beam has a cross section of b = 18 in., h = 26 in., and d = 23.5 in. It is reinforced with four No. 5 Grade 60 bars. The concrete strength is 7,600 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.

Determine the size modification factor, ψs, for a rectangular beam with b = 18 in. and d = 23 in., three epoxy-coated No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 40 stirrups located every 6 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.75 in.