2

WSD = — x 10 ft x 150 = 250 plf (3 . 6 kN/m) 250(72)2

Md + Msd = 4,984,416 + 1,944,000 = 6,928,416 in. lb (783 kN m) ft _ _ pe A _ £c£t\ _ Md + MSD

615 97 5 960

= +432 . 5 _ 1,162 . 5 = _730 psi (5 .0 MPa) < 0 .45fc' = _2 .250 psi, OK

— -2426. 33 + 2550 .02 — +123 .7 (0 .85 MPa), say 124 psi (T), OK

This is a very low tensile stress when the unshored slab is cast and before the service load is applied, <12f — 849 psi .

C. At service load for the precast section. Section modulus for composite section at the top of the precast section is t 77,118 3

280(72)2

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