Problem $2$

Solve Problem $12\mathrm{.}2$ in the textbook. You may use Graph A$.3$ in the book to determine the bar cutoff points. Check the development lengths of the flexural reinforcement. For the left end of the exterior span, determine the dimensions of the standard hooks needed to develop the negative moment reinforcement in the supporting beam. In addition to the flexural reinforcement, also determine the size and spacing of the temperature and shrinkage steel needed. You may skip the bar size check at the zero moment points.

$12\mathrm{.}2.$ A reinforced concrete building floor system consists of a continuous one$-$way slab built monolithically with its supporting beams, as shown in cross section in Fig. P$12\mathrm{.}2.$ Service live load is $125$ psf$.$ Dead loads include a $10$ psf allowance for nonstructural lightweight concrete floor fill and surface, and a $10psf$ allowance for suspended loads, plus the self$-$weight of the floor. Using ACI coefficients from Chapter $11,$ calculate the design moments and shears and design the slab, using a maximum tensile reinforcement ratio of $0\mathrm{.}006.$ Use all straight bar reinforcement. One$-$half of the positive$-$moment bars will be discontinued where no longer required; the other half will be continued into the supporting beams as specified by the ACI Code. All negative steel will be discontinued at the same distance from the support face in each case.

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DESIGN OF CONCRETE STRUCTURES Chapter $12$

Summarize your design with a sketch showing concrete dimensions, and size, spacing, and cutoff points for all reinforcement. Material strengths are $f_y=60,000$ psi and $f_c^{\text{'}}=3000$ psi.

FIGURE P$12\mathrm{.}2$