There are ACI Code requirements placed on structural integrity of cast-in-place reinforced concrete construction, precast construction, and prestressed concrete slabs.

As the size of coarse aggregate increases, the roughness of the crack decreases. This allows higher shear stresses to be transferred across the crack.

A rectangular beam with cross section b = 16 in., h = 22 in., and d = 19.5 in. supports a total factored uniform load of 1.60 kips/ft, including its own dead load. The beam is simply supported with a 18-ft span. It is reinforced with five No. 5 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 4,200 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. The strength of the five bars is φMn = 130.3 kip-ft, and the strength of the remaining two bars is φMn = 53.5 kip-ft. Determine the distance from the support to the theoretical cutoff point (i.e. disregard ACI 318-14 Section 9.7.3.3).

Compute φVn for the cross section shown. Assume f’c = 4,000 psi, fyt = 60,000 psi, b1 = 28 in., b2 = 14 in., d1 = 4 in., d2 = 15 in., and that there are three No. 9 longitudinal tension bars and No. 4 stirrups at 10 in. o.c.

Axial compression tends to increase shear strength.

Which symbol represents the bar location factor?

A rectangular beam has a cross section of b = 14 in., h = 30 in., and d = 27.5 in. It is reinforced with two No. 7 Grade 60 bars. The concrete strength is 7,300 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. Determine the strength φMn for this beam.

Bond stresses must be present where the force in a reinforcement bar changes along its length.

Compute φVn for the cross section shown. Assume f’c = 7,000 psi, fyt = 40,000 psi, b1 = 27 in., b2 = 10 in., d = 27 in., h1 = 7 in., h2 = 16 in., h3 = 9 in., t = 8 in., and that there are six No. 6 longitudinal tension bars and No. 4 stirrups at 9 in. o.c.

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