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- Design of shear reinforcement
- Shear strength of concrete
- Shear reinforcement
- Effective depth
- Maximum shear strength permitted
- Location of Critical Section
- Minimum shear reinforcement
- Bar placement
- Design of Flexural reinforcement

1. The shear strength, fV_{n}
must equal or be greater than the factored shear, V_{u}

fV_{n} ³ V_{u}
ACI eq (11-1)

where f = 0.75 is strength reduction factor, and

V_{n} = V_{c} +
V_{s } _{ }ACI
eq (11-2)

where V_{c} is
shear strength of concrete, and V_{s} is
strength of shear reinforcement.

2. Shear strength of concrete shear wall shall be calculated as

a. V_{c} = 2 Öf_{c}'
h d

Or the lesser of

b. V_{c} = 3.3 Öf_{c}'
h d + N_{u} d/ (4 *l*_{w})
ACI eq (11-29)

c. V_{c} = { 0.6 Öf_{c}'
+ *l*_{w} (
1.25 Öf_{c}'
+ 0.2 [N_{u}/(*l*_{w}* h)]) /( M_{u}/V_{u} - *l*_{w}/2)}
h d ACI eq (11-30)

(It does not apply when M_{u}/V_{u} - *l*_{w}/2
< 0)

where f_{c}' is compressive strength of concrete,

h is thickness of the wall,

d is effective depth,

*l*_{w }is
overall length of wall.

N_{u }is axial
force, positive for compression, negative for tension,

M_{u} is moment
parallel to the direction of the wall.

shear strength provided by horizontal shear reinforcement shall be calculated aS

V_{s} = A_{v} f_{y} d
/s
ACI eq. (11-31)

where A_{v} is
area of reinforcement, f_{y} is
yield strength of reinforcement, d is effective depth, and s is
spacing of reinforcement.

fV_{n }=
10 Öf_{c}'
ACI section 11.10.3

1. d = 0.8 *l*_{w}

_{2. Calculate based on strain compatibility analysis (same as in
a beam section).}

1. One-half of the wall height.

2. *l*_{w }/2

whichever is smaller.

1. Minimum horizontal shear reinforcement ratio to gross
section area, r_{t} =
0.0025.

2. Minimum vertical shear reinforcement ratio to gross section area,

r_{l} =
0.0025 + 0.5 (2.5 - h_{w}/ *l*_{w} )( r_{t} -
0.0025) ³
0.0025
ACI eq. (11-32)

and need not be greater than calculated based on ACI eq. 11-31.

1. Minimum vertical wall reinforcement: (Section 14.3.2)

a. 0.0012 for deformed bars smaller than #5 and fy > 6000 psi

b. 0.0015 for deformed bars #5 or larger

2. Minimum horizontal wall reinforcement: (Section 14.3.3)

a. 0.0020 for deformed bars smaller than #5 and f_{y}
> 6000 psi

b. 0.0025 for deformed bars #5 or larger.

a. *l*_{w }/5.
b. 3 h c. 18 inches.

2. Bar shall be placed uniformly across the length and height of walls

Design as a cantilever beam:

fM_{n} ³ M_{u}

Design as a column subject to axial load and bending

fP_{n} ³ P_{u}

fM_{n} ³ M_{u}

Flexural reinforcement shall be placed at each end of walls