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Structural Concrete - Hassoun

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

s ≤ d/2<br />

h<br />

2 in.<br />

2h<br />

Figure 20.14<br />

Transverse reinforcement requirements.<br />

6d b ≥ 3 in.<br />

Extension<br />

Detail B<br />

6d b<br />

Extension<br />

Crosstie as<br />

defined in ACI 25.3.5<br />

Detail A<br />

Consecutive<br />

crossties engaging<br />

the same<br />

longitudinal bars<br />

have their 90 deg<br />

hooks on opposite<br />

sides<br />

Detail C<br />

B<br />

A<br />

A<br />

C<br />

C<br />

Maximum spacing<br />

between bars<br />

restrained by legs<br />

of Crossites<br />

or hoops = 14 inch<br />

Figure 20.15<br />

Institute [1]<br />

Transverse reinforcement requirements. Courtesy of American <strong>Concrete</strong><br />

4. Transverse reinforcement should be designed to resist the design of the shear force<br />

(Figs. 20.14 and 20.15). Design of the shear force for flexural members of special moment<br />

frames can be determined using the following equation (Fig. 20.16):<br />

V 1 = M− pr + M + pr<br />

l n<br />

V r = M− pr + M + pr<br />

l n<br />

+ w ul u<br />

2<br />

+ w ul u<br />

2<br />

(20.38a)<br />

(20.38b)

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