25 10

wmax = wmaxRi = 0 .0083 x 1.31 = 0 .011 in . (0 .28 mm) Afs = 30 ksi

2 540

3 30

From this solution, it is evident that every prestressed concrete beam would satisfy the ACI Code requirements for crack control regardless of the loading conditions and/or overloading, or environmental conditions. It is rare that prestressed or mild steel reinforcement would ever be spaced within a flange that can violate the code spacing requirements. Hence, the code provisions are not effective, and probably rarely would they be effective for crack control even in two-way prestressed concrete plates.

8.8.10 SI Deflection and Cracking Expressions

where f is in MPa units and wc is in kg/m3 ranging between 1500 and 2500 kg/m3. For f0 > 35 MPa, < 80 MPa

For normal-weight concrete, Ec = 3 . 32 vf + 6895 MPa fr = 0 . 62 vf

0 0

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