Page 73 - Advanced Design Examples of Seismic Retrofit of Structures

Example of a Two-Story Unreinforced Masonry Building Chapter 2 65

H s ¼ 1:8+1:2 ¼ 3:0m
1
K ¼ 3
H
e H e
+
12E m I g A v G m
1
K 1 ¼ 3 ¼ 2,986,474kgm
2:4 2:4
+
12 203,900,000 0:02 0:35 0:93 78,423,077
For Wall#105:
1:5
H e ¼ 1:8+ ¼ 2:55m
2
H s ¼ 1:8+1:5 ¼ 3:3m

t W H 3 o
I o ¼
12
0:35 1:5 3 4
I o ¼ ¼ 0:098m
12
1
K ¼
H 3 1
e H e
+ +
3E m I g A v G m 4E m I g + 6E m I o
2 2
H H e H L o
s s
1
K 105 ¼
2:55 3 2:55 1
+ +
3 2:04E +8 0:02 0:35 :93 78423077 4 2:04E +8 0:02 + 6 2:04E +8 0:098
2
2
3:3 2:55 3:3 1:83
¼ 712313kgm
The X- and Y-coordinates of the center of rigidity are determined based on
Eqs. (2.17) and (2.18), respectively.
X
n y
K iy d ix
i¼1
n y
X CR ¼ X (2.17)
K iy
i¼1
X
n x
K ix d iy
i¼1
Y CR ¼ X (2.18)
n x
K ix
i¼1
where:
n x and n y ¼number of walls in X- and Y-direction, respectively;
K ix and K iy ¼ ith wall’s in-plane stiffness for walls in X- and Y-direction,
respectively;