Page 404 - Advanced Design Examples of Seismic Retrofit of Structures

362 Advanced Design Examples of Seismic Retrofit of Structures

TABLE 5.32 Comparison of the Story Stiffness With That in the Adjacent
Stories
80% Average
K i 70% K i
Direction Story (MN/m) (MN/m) K i (MN/m) Result
X 1st 714 500 571 OK
Floor 2500 – – OK
Y 1st 263 184 210 OK
Floor 909 – – OK

5.11.5 Analysis Procedure

5.11.5.1 Demand Forces Calculations
The procedure is similar to that in Section 5.6.1.
Based on the derived natural periods from the model, we have:
- For the main building:
0:7 0:21 0:7 0:24
C 1 xðÞ ¼ 1+ ¼ 1:41,C 1 yðÞ ¼ 1+ ¼ 1:38
1:4 0:2 1:4 0:2
C 2 ¼ 1:0 ) V XðÞ ¼ 1:16W
C m ¼ 1:0 V YðÞ ¼ 1:14W
S axðÞ ¼ S ayðÞ ¼ 0:3 2:75 ¼ 0:825

- For the sports building:
0:7 0:17
C 1 xðÞ ¼ C 1 yðÞ ¼ 1+ ¼ 1:44
1:4 0:2 V XðÞ ¼ 1:19W
C 2 ¼ 1:0 )
C m ¼ 1:0 V YðÞ ¼ 1:19W
S axðÞ ¼ S ayðÞ ¼ 0:3 2:75 ¼ 0:825

5.11.5.2 Target Displacement
The procedure is similar to that in Section 5.5.3. We have:
2
δ ¼ 1:2 1:4 1:2 0:825 ð 0:21Þ 9:81 ¼ 1:84 cmÞ 1:5 ¼ 2:75 cmÞ
ð
ð
txðÞ
39:43
2 and
ð 0:24Þ
δ ¼ 1:2 1:4 1:2 0:825 9:81 ¼ 2:35 cmÞ 1:5 ¼ 3:53 cmÞ
ð
ð
txðÞ
39:43
For the main building;