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Structural Concrete - Hassoun

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818 Chapter 20 Seismic Design of Reinforced <strong>Concrete</strong> Structures<br />

V 1 V 2<br />

V<br />

T<br />

C m<br />

e x = 19.3 ft<br />

Figure 20.10<br />

Example 20.5: Torsional effect.<br />

Therefore, V 1 = 5.4 + 1.6 = 7 K. For wall 2, shear force V 2 is<br />

V 2 =<br />

25<br />

25 + 25 + 10 + 10 (15) =2.1K (duetoV y )<br />

V 2 = 2 × 25 × 25.7 2 + 2 × 10 × 64.3 2 ∕289.5(10 × 64.3) =1.6kip⋅ ft(duetoT)<br />

Therefore, V 2 = 2.1 + 1.6 = 3.7 K.<br />

20.4 LOAD COMBINATIONS<br />

A structure should be designed to resist the combined effects of loading cases. For basic load combinations<br />

for strength design follow IBC 2012, Section 1605.2:<br />

1. 1.4(D + F)<br />

2. 1.2(D + F) + 1.6(L + H) + 0.5(L r or S or R)<br />

3. 1.2(D + F) + 1.6(L r or S or R) + 1.6H + (f 1 L or 0.5W)<br />

4. 1.2(D + F) + 1.0W + f 1 L + 1.6H + 0.5(L r or S or R)<br />

5. 1.2(D + F) + 1.0E + f 1 L + 1.6H + f 2 S<br />

6. 0.9D + 1.0W + 1.6H<br />

7. 0.9(D + F) + 1.0E + 1.6H<br />

where<br />

f 1 = 1.0 for floors in places of public assembly, for live loads in excess of 100 psf, and for parking<br />

garages live loads<br />

f 1 = 0.5 for other live loads<br />

f 2 = 0.7 for roof configurations (such as saw tooth) that do not shed snow off structure<br />

f 2 = 0.2 for other roof configurations<br />

D = dead load<br />

L = live load excluding roof live load<br />

L r = roof live load<br />

S = snow load<br />

R = rain load<br />

W = wind load<br />

E = seismic load effect<br />

H = soil lateral load

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