A rectangular beam has a cross section of b = 14 in., h = 26 in., and d = 23.5 in. It is reinforced with two No. 6 Grade 60 bars. The concrete strength is 8,500 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the neutral axis location of the cracked beam (measured from the top of the beam).

Concrete cover may be decreased to increase a member’s fire resistance.

Determine the lightweight modification factor, λ, for a rectangular beam with b = 17 in. and d = 24 in., three galvanized No. 9 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 4 Grade 60 stirrups located every 8 in. along the span. Assume 7,000-psi lightweight concrete and a clear cover of 2 in.

Determine the epoxy modification factor, ψe, for a rectangular beam with b = 18 in. and d = 20 in., four epoxy-coated No. 8 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 10 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 1.5 in.

Heat-of-hydration cracking can be prevented by proper mix design and by preventing rapid drying of the surface during the first hour or so after placing.

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 24 in. and No. 3 stirrups. This beam has three No. 9 bars as longitudinal reinforcement. The clear cover is 1.9 in.

Failure of a hooked anchorage almost always involves crushing of the concrete inside the hook.

A rectangular beam has a cross section of b = 14 in., h = 28 in., and d = 25.5 in. It is reinforced with five No. 5 Grade 60 bars. The concrete strength is 5,500 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the modulus of rupture of the concrete, fr.

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

Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 18 in. and No. 3 stirrups. This beam has four No. 7 bars as longitudinal reinforcement. The clear cover is 1.8 in.