Page 491 - Design of Reinforced Masonry Structures

SHEAR WALLS 7.53

Design diaphragm at level x is F , given by Eq. (7.66):
px
n
∑ F
F = ix i w
=
px n px
∑ w i
=
ix
Value given by the above equation has the following limits on it:
0.2 S Iw ≤ F ≤ 0.4 S Iw px
DS
DS
px
px
Level 5:
⎛ 80 1 . ⎞
F = ⎜ ⎟ 400( ) = 80 1. kips
px ⎠
⎝ 400
0.2S Iw = 0.2(0.6)(1.0)(400) = 48 kips
px
DS
0.4S Iw = 0.4(0.6)(1.0)(400) = 96 kips
px
DS
48 < 80.1 < 96 kips
Therefore, F = 80.1 kips
px5
Level 4:

⎛ 80 1 . + 72 1 . ⎞
F = ⎜ ⎟ 450( ) = 80 6. kips
px
⎝ 400 + 450 ⎠
0.2S Iw = 0.2(0.6)(1.0)(450) = 54 kips
DS
px
0.4S Iw = 0.4(0.6)(1.0)(450) = 108 kips
px
DS
54 < 80.6 < 108 kips
Therefore, F = 80.6 kips
px4
Level 3:

+
+
.
.
.
F px3 = ⎜ ⎛ ⎝ 80 1 72 1 60 1 ⎞ ⎟ ( 500 =) 7886.kips
400 450 500 ⎠
+
+
0.2S Iw = 0.2(0.6)(1.0)(500) = 60 kips
DS
px
0.4S Iw = 0.4(0.6)(1.0)(500) = 120 kips
DS
px
60 < 78.6 < 120 kips
Therefore, F = 78.6 kips
px3