Page 305 - Advanced Design Examples of Seismic Retrofit of Structures

294 Advanced Design Examples of Seismic Retrofit of Structures

- For the sports building
0:7 2:31 0:7 0:3
C 1 xðÞ ¼ 1+ ¼ 0:341 ! C 1 xðÞ ¼ 1:0, C 1 yðÞ ¼ 1+ ¼ 1:33
1:4 0:2 1:4 0:2
C 2 ¼ 1:0
C m ¼ 1:0
S axðÞ ¼ 0:3 1:23 ¼ 0:369
S ayðÞ ¼ 0:3 2:75 ¼ 0:825

V XðÞ ¼ 0:369 W
)
V YðÞ ¼ 1:097 W

5.5.2 Distribution of Demand Forces in Height of the Building

The seismic force applied at any floor level i, F UDi , is determined based on Eq.
(5.12):

W i h k i
n Q E (5.12)
F UDi ¼ X k
W j h
j¼1 j
where:
Q E ¼pseudo-lateral force based on Eq. (5.5);
k ¼vertical distribution factor;
k ¼2.0 for T 2.5s;
¼1.0 for T 0.5s;
¼0.5T +0.75 for 0.5< T <2.5s;
W j ¼portion of the effective seismic weight W located on or assigned to
level j;
W i ¼portion of the effective seismic weight W located on or assigned to
level i;
h j ¼height from the base to level j; and
h i ¼height from the base to level i.

T X ¼ 0:49 secð Þ k ¼ 1:0
) For the main building
T Y ¼ 0:42secÞ k ¼ 1:0

T X ¼ 2:31 secð Þ k ¼ 0:5T +0:75 ¼ 0:5 2:3+0:75 ¼ 1:9
)
T Y ¼ 0:3 secð Þ k ¼ 1:0
For the sports building

5.5.3 Target Displacement

The target displacement, δ t , at each floor level shall be calculated in accordance
with Eq. (5.13):