Determine the bar-spacing factor, cb, for a simply supported rectangular beam with b = 18 in. and No. 3 stirrups. This beam has five No. 8 bars as longitudinal reinforcement. The clear cover is 1.5 in.

A rectangular beam with cross section b = 14 in., h = 22 in., and d = 19.5 in. supports a total factored uniform load of 2.20 kips/ft, including its own dead load. The beam is simply supported with a 23-ft span. It is reinforced with five No. 7 Grade 60 bars, three 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 3,300 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 five bars is φMn = 232.3 kip-ft, and the strength of the remaining two bars is φMn = 100.3 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

Unlike exact bond stresses, the average bond stresses vary from point to point between cracks.

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 top of the beam, and No. 3 Grade 60 stirrups located every 12 in. along the span. Assume 4,000-psi normal-weight concrete and a clear cover of 1.5 in.

A rectangular beam has a cross section of b = 14 in., h = 24 in., and d = 21.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 9,400 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the cracked moment of inertia, Icr. The neutral axis location of the cracked beam (measured from the top of the beam) is 4.1442 in.

A rectangular beam has a cross section of b = 16 in., h = 26 in., and d = 23.5 in. It is reinforced with five No. 7 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.

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

A hooked bar can resist pull-out more effectively if _______.

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.