This value is higher than the previously determined out-of-plane shear forces on the wall (547 lb / 40" =
164 plf ). Therefore, use 410 plf (5.98 KN/m) for the anchorage of the interior CMU walls for out-of-
plane forces.
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Exterior walls A1-A2 & I1-I2
At top of wall: Wn = (57 psf)[(10'2) + (1'parapet)] = 342 plf
/
At mezz level: Wn = (57 psf)(5'top + 5'below) = 570 plf (8.32 KN/m) > 342 plf (4.99 KN/m)
Design all walls for out-of-plane anchorage force of 570 plf (8.32 KN/m)
Standard reinforcement details for CMU shear walls
Typical CMU wall reinforcing details are taken from Figures 7-14 7-16 and Section 7-2.h.(3)(h).6.iii .
Additional development requirements are taken from FEMA 302 Section 11.4.5
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Embedment length, ld: The embedment length of reinforcing bars is determined as:
ld = 0.0015dbFs
ACI 530 Eq. 8-1
For #4 bar: ld = 0.0015(4/8)(24000) = 18" (46 cm)
For #5 bar: ld = 0.0015(5/8)(24000) = 22.5", use 24" (61 cm)
For #6 bar: ld = 0.0015(6/8)(24000) = 27", use 28" (71 cm)
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Lap Splices: The minimum length of lap for bars in tension or compression is taken as:
ld = 0.002dbFs
ACI 530 Eq. 8-2
For #4 bar: ld = 0.002(4/8)(24000) = 24" (61 cm)
For #5 bar: ld = 0.002(5/8)(24000) = 30" (76 cm)
For #6 bar: ld = 0.002(6/8)(24000) = 36" (91 cm)
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Standard hooks: The typical standard hook for this structure (per FEMA 302 Sec. 11.4.5.3) shall be a
180 degree turn plus extension of at least 4db but not less than 2.5"(64mm), a 135-degree turn plus
extension of at least 6 bar diameters at free end of bar, or a 90-degree turn plus extension of at least
12 bar diameters at free end of bar.
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Shear reinforcement: The shear shall extend to a distance d from the extreme compression face and
shall be carried as close to the compression and tension surfaces of the member as cover requirements
and the proximity of other reinforcement permit. Shear reinforcement shall be anchored at both ends
for its calculated stress. The ends of a single leg shall be anchored by a standard hook plus an
effective embedment of 0.5 ld ACI 530 Sec. 8.5.6
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Horizontal reinforcement at openings: Horizontal reinforcement of at least one #4 bar shall be placed
on both sides of openings and extend a minimum of 24" (61cm) or 40db (Sec. 7.2.h.3.(h).6.)
For #5 bars, 40db = 40(5/8) = 25" >24", use 25" (64 cm).
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Minimum wall reinforcement: All walls shall be reinforced with both vertical and horizontal
reinforcement. The sum of the areas of horizontal and vertical reinforcement shall be at least 0.002
times the gross cross-sectional area of the wall and the minimum area of reinforcement in each
direction shall not be less than 0.0007 times the gross cross-sectional area of the wall (per FEMA 302
Sec. 11.3.8.3).
H1-46
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