Page 494 - Design of Reinforced Masonry Structures

7.56 CHAPTER SEVEN

120'

80'
V

Roof plan
Roof diaphragm

10'
20'

80'
Elevation
FIGURE E7.11

1. Calculate S and S :
DS
D1
2 2
S DS = S MS = F S s
a
3 3

2
2
S = S = F S
D1 Mi v 1
3 3
From Table 7.2, by interpolation for Site Class D, for S = 0.552
S
⎛ 14 . −12 . ⎞
−
F = 14 . + ⎜ ⎟ 0552 05 . ) = 13 . 558
(.
a ⎝ 075 − 05 . ⎠
.

1 358 0 552 =)( .
S DS = 2 F S = 2 (. ) 0 5 .
s
a
3 3
1
From Table 7.3 by interpolation for Site Class D, for S = 1.914
⎛ 20 . −18 . ⎞
−
(.
4
F = 20 . − ⎜ ⎟ 0243 02 . ) = 1914
.
v ⎠
⎝ 03 . − 02 .
2 2
S D 1 = F S = (. ) 0 31
.
1 914 0 243 =)( .
1
a
3 3
2. Calculate seismic response coefficient C
s
C = S DS = . 05 = . 010
s
/ . ) 0
( RI / ) (51