When a section cracks, its moment of inertia increases, leading to a decrease in the stiffness of the beam.

Eccentricity in a column may arise from balanced moments in the beams, alignment of the column between floors, even compaction of the concrete across the width of the section, and/or alignment of the reinforcement.

A rectangular beam has a cross section of b = 14 in., h = 28 in., and d = 25.5 in. It is reinforced with three No. 6 Grade 60 bars. The concrete strength is 3,400 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 5.7067 in.

Ties do not act as shear reinforcement for columns.

Determine the required splice length for the galvanized 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 = 26 in.Column thickness, h = 14 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 10Size of longitudinal bars = No. 8Size of ties = No. 3Concrete strength = 6,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Use the interaction diagrams found in Appendix A of the textbook to determine whether the following rectangular tied column with bars in 4 faces can safely support a load of Pu = 1,400 kip and Mu = 914.7 kip-ft.b = 20 in.h = 28 in.fc’ = 4 ksify = 60 ksiγ = 0.75ρg = 0.02

Rust does not cause cracks to expand because it occupies the same volume as the metal from which it is formed.

Compute the maximum bar spacing, s, to control for cracks in a one-way slab with 2.2 in. of clear cover and f​y​ = 58 ksi.

Columns with ties generally exhibits more ductility than columns with spirals.

The ACI Code defines 0.02 as the maximum usable compressive strain for reinforced concrete.