Page 486 - Design of Reinforced Masonry Structures

7.48 CHAPTER SEVEN

Example 7.9 Design base shear and distribution of the base shear over
the building height.
Determine the base shear and its distribution over the height of a building that con-
sists of a building frame system with special reinforced masonry shear walls (Fig. E7.9).
The building is assigned Seismic Design Category D and importance factor I = 1.0. It
is located in a seismic region for which spectral acceleration parameters S and S have
S 1
been determined, respectively, as 0.90g and 0.45g. The site class for building site has
been determined as C. The seismic weight assigned to various levels is as follows:

60'

FIGURE E7.9

Level 1: 650 kips
Level 2: 600 kips
Level 3: 500 kips
Level 4: 450 kips
Level 5: 400 kips
Solution
Given:
S = 0.90g
S
S = 0.45g
1
Seismic design category = D
Site class = C
I = 1.0
1. Determine S
DS 2
S DS = 3 S MS

From Table 7.2, S = 0.98g, F ≈ 1.0
S a
S = F S = 1.0(0.90) = 0.90
s
MS
a
2
S = (090 ) = 060.
.
DS
3
S = 2 S
D1 M1
3
S M1 = F S = (1.35)(0.45) = 0.61
v
1