Simplified Design for Structural Walls - Simplified Design of Reinforced Concrete Buildings - page 194

Try an 8 in. wall thickness. To accommodate openings required for stairwells, provide 8 ft flanges as shown in
Fig. 6-2.

From Table 10-1, for a fire resistance rating of 2 hours, required wall thickness = 4.6 in. ≤ 8 in. O.K.

E-W direction
A g = (248 8) + (88 8 2) = 1984 + 1408 = 3392 in. 2

x = [(1984 4) + (1408 52)]/3392 = 23.9 in.

I y = [(248 28.1 2 )] = 2,816,665 in. 4

For two walls: I (walls) = 2(2,816,665) = 5,663,330 in. 4 >> 773,088 in. 4

8 3 /12) + (1984 19.9 2 )] + [2(8 88 3 /12) + (1408

N

Exit stair

Exit stair

16" x 16" typ. Enclosure

walls

Enclos ure
walls

12" x 12" typ.

Figure 6-1 Plan of Building #2, Alternate (2)

8 " ty p.

y

c.g.

x

x =23.9"

96"
(8"-0")

Figure 6-2 Plan View of Shearwall