Page 164 - Advanced Design Examples of Seismic Retrofit of Structures

156 Advanced Design Examples of Seismic Retrofit of Structures

TABLE 3.11 Seismic Forces Coefficients

Natural Period of the Building T x, y 50.05×41.25 0.75 50.8s
T s T
C 1 C 1 ¼ 1+ 2T s 0:2 ¼ 1
C 2 C 2 ¼1.0
S a (Earthquake-1) S a ¼(A g)
B¼0.35 9.81 B¼3.43B
Seismic forces coefficient in X and Y directions C 1 C 2 S a ¼1 1 3.43B¼3.43B
(Earthquake-1)
S a (Earthquake-1) S a ¼1.5(A g)B¼1.5
(0.35 9.81 B)¼5.14B
Seismic forces coefficient in X and Y directions C 1 C 2 S a ¼1 1 5.14B¼5.14B
(Earthquake-2)

We have:

Q E LDP ¼ ABW ¼ 0:35 1:94W ¼ 0:68W
In the linear dynamic procedure, all the demand forces and deformations
are multiplied by coefficients C 1 and C 2 . The seismic forces coefficients are
presented in Table 3.11.

3.5.1.2 Action Calculation
Deformation-Controlled

Based on Code 360, deformation-controlled actions for LDP denoted by Q UD
shall be calculated in accordance with Eq. (3.5):
(3.5)
Q UD ¼ Q G + Q E
where:
Q E ¼action caused by the response to the selected seismic hazard level
calculated using Section “Seismic Loads” of this example; and
Q G ¼action caused by gravity loads as determined according to either of
these methods:
1) Where the effects or actions of gravity loads and seismic forces are additive,
the action caused by gravity loads, Q G , shall be obtained in accordance
with Eq. (3.6):
Q G ¼ 1:1 Q D + Q L + Q s Þ (3.6)
ð