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Compute the maximum bar spacing, s, to control for cracks in a one-way slab with 1.5 in. of clear cover and f​y​ = 70 ksi.

Weakening of concrete near the top of a column is due to upward migration of water in the fresh concrete.

Column ties increase the unsupported length of the longitudinal bars, thus reducing the danger of buckling.

Spiral columns are often used in situations where ductility is unimportant.

Due to how tedious the strength calculations can be for reinforced concrete columns, it is generally preferred to use interaction diagrams to design them.

A rectangular beam has a cross section of b = 18 in., h = 30 in., and d = 27.5 in. It is reinforced with three No. 5 Grade 60 bars. The concrete strength is 6,100 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the cracking moment, Mcr.

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

The textbook author recommends the use of 180° stirrups throughout, except in certain cases where 90° stirrups are needed to prevent overlap.

Tied columns have lower ductility giving less warning before a failure.

In a typical construction cycle, the reinforcement and concrete for the columns are placed after the reinforcement and concrete for the beams and slabs in a floor system above it.