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Structural Concrete - Hassoun

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Review Problems on <strong>Concrete</strong> Building Components 963<br />

Vu = 21.84 K<br />

ϕ<br />

V c<br />

2<br />

= 12.81 K<br />

Minimum reinforcement<br />

79.40″<br />

No reinforcement<br />

192″<br />

112.60″<br />

Figure 23.13<br />

Shear distribution diagram from the face to midspan of beam.<br />

First no. 3 stirrup at s/2 = 11/2 = 5.5 in.<br />

Seven no. 3 stirrups at 11 in. = 77 in.<br />

Total = 77 + 5.5 in. = 82.5 in.<br />

Minimum reinforcement<br />

79.41″<br />

No reinforcement<br />

192″<br />

112.59″<br />

12″<br />

192″<br />

25″<br />

5.5″11″<br />

Figure 23.14<br />

Bar distribution for shear reinforcement.<br />

10. Check development length<br />

The development length l d for no. 3 tension bars at support A can be determined as follows:<br />

Check if conditions for spacing and cover are met to select an equation. (ACI Code,<br />

Section 25.4.2.2)<br />

d b = 0.375 in.<br />

Since clear cover = 2in.>d b<br />

and clear spacing = 12 − 5 − 0.375 = 6.625 in. >2d<br />

1<br />

b<br />

Condition met. Use l d =<br />

f y Ψ t Ψ e<br />

20λ √ f (d ′<br />

b )<br />

c

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