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A rectangular beam has a cross section of b = 16 in., h = 28 in., and d = 25.5 in. It is reinforced with three No. 7 Grade 60 bars. The concrete strength is 5,200 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the assumed modulus of elasticity of the concrete, Ec.

Why is the concrete near the top of a column weaker than the concrete in the rest of the column?

Compute the maximum bar spacing, s, to control for cracks in a one-way slab with 2.4 in. of clear cover and f​y​ = 68 ksi.

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. 7 Grade 60 bars. The concrete strength is 6,400 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).

Determine the required splice length for the epoxy-coated longitudinal bars in the following tied column made of normal-weight concrete. Assume that some of the longitudinal bars are in tension and that the connection should be designed as a Class B contact lap splice. Use ACI 318-14 Table 25.4.2.2 to calculate the development length, and assume that the ties satisfy the Code minimum.Column width, b = 28 in.Column thickness, h = 16 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 6Size of longitudinal bars = No. 8Size of ties = No. 3Concrete strength = 9,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Compute φVn for the cross section shown. Assume f’c = 7,000 psi, fyt = 60,000 psi, b1 = 32 in., b2 = 11 in., d1 = 7 in., d2 = 15 in., and that there are three No. 8 longitudinal tension bars and No. 4 stirrups at 10 in. o.c.

For a transformation on a reinforced concrete beam, the _______ of concrete is considered when a crack is formed. When there is no crack, the _______ of the concrete is considered.

The minimum number of longitudinal bars in a circular column is eight.

What does the symbol f​r ​represent in the transition from I​g​ to I​cr ​equation?

Compute the axial compressive strength Pn and moment capacity Mn of the following tied column when the largest strain in the concrete is 0.003 and the strain in the tension reinforcement is 0.003. Note that you should not include φ in the answer and that you should not consider Pn,max.b = 14 in.h = 22 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 6Size of longitudinal bars = No. 9Size of ties = No. 4Concrete strength = 8,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 60,000 psi