Civil Engineering Reference
In-Depth Information
0.08
0.07
D
b
0.06
0.05
0.04
0.03
0.02
a
0
2
0.01
0
0.0
3.0
6.0
9.0
12.0
15.0
Time (seconds)
0.08
D =
Σ
t
i
0.07
t
i
0.06
0.05
0.04
0.03
0.02
a
0
2
0.01
0
0.0
3.0
6.0
9.0
12.0
15.0
Time (seconds)
100
AI
f
75
50
25
D
s
AI
0
0
0.0
3.0
6.0
9.0
12.0
15.0
Time (seconds)
Figure 3.21
D e fi nition of duration of earthquake strong motion: bracketed (
top
), uniform (
middle
) and signifi cant
(
bottom
) duration (
courtesy
of Pacifi c Earthquake Engineering Research Center, USA)
