3. Wall Structural Analysis

Using 14.8 provisions, calculate factored loads as follows for each of the considered load combinations:

04 10DT24

3.1. Roof load per foot width of wall

3.2. Calculation of maximum wall forces

The calculation of maximum factored wall forces in accordance with 11.8 is summarized in Figure 2 including moment magnification due to second order (P-Δ) effects.

05 PCA Notes

Figure 2 - Wall Structural Analysis According to the Alternative Design of Slender Walls Method (PCA Notes)

For load combination #1 (U = 1.4 D):

ACI 318-14 (11.8.3.1d)

Where Mua is the maximum factored moment at midheight of wall due to lateral and eccentric vertical loads, not including PΔ effects.

ACI 318-14 (11.8.3.1)

ACI 318-14 (19.2.2.1.b)

ACI 318-14 (11.8.3.1c)

ACI 318-14 (11.8.3.1)

Calculate the effective area of longitudinal reinforcement in a slender wall for obtaining an approximate cracked moment of inertia.

ACI 318-14 (R11.8.3.1)

The following calculation are performed with the effective area of steel in lieu of the actual area of steel.

ACI 318-14 (11.8.3.1c)

Therefore, section is tension controlled

ACI 318-14 (Table 21.2.2)

ACI 318-14 (Table 21.2.2)

ACI 318-14 (11.8.3.1d)

The steps above are repeated for all the considered load combinations, Table 1 shows the factored loads at mid-height of wall for all of these load combinations.

Table 1 - Factored load combinations at mid-height of wall

Load Combination

Pu,

kips

Mua,

in.-kips

Ec,

ksi

n

Ase,w,

in.2/ft

a,

in.

c,

in.

Icr,

in.4

εt,

in./in.

ϕ

Mu,

in.-kips

1.4 D

4.21

3.74

3,605

8

0.34

0.50

0.58

32.4

0.0176

0.9

5.25

1.2 D + 1.6 Lr + 0.8 W

5.04

19.53

3,605

8

0.35

0.52

0.61

33.4

0.0168

0.9

29.38

1.2 D + 0.5 Lr + 1.6 W

4.05

32.61

3,605

8

0.33

0.49

0.58

32.3

0.0178

0.9

45.22

0.9 D + 1.6 W

2.70

31.21

3,605

8

0.31

0.46

0.54

30.7

0.0193

0.9

38.80

3.3. Tension-controlled verification

ACI 318-14 (11.8.1.1(b))

For this check use the largest Pu (5.04 kips) from load combination 2 to envelop all the considered combinations.

Therefore, section is tension controlled

ACI 318-14 (Table 21.2.2)