Guralp Systems ART - Manual (Page 32)

ART
25. number of absolute effective cycles (peak counting
excluding non-zero crossings) in acceleration time-
history (Hancock & Bommer, 2005);
26. number of equivalent effective cycles using user-
defined damage exponent (peak counting excluding
non-zero crossings) in acceleration time-history
(Hancock & Bommer, 2005);
27. number of absolute effective cycles (rainflow counting
technique) in acceleration time-history (Hancock &
Bommer, 2005);
28. number of equivalent effective cycles using user-
defined damage exponent (rainflow counting
technique) in acceleration time-history (Hancock &
Bommer, 2005);
29. predominant spectral period (or frequency) defined by
Rathje et al. (2004) as the period at which the
maximum spectral acceleration (using user-defined
damping level) occurs;
30. mean period (or frequency) defined by Rathje et al.
(2004) as:
where C
i
are Fourier amplitudes at frequencies f
i
;
31. smoothed predominant spectral period (or frequency)
defined by Rathje et al. (2004) as:
for T
i
with SA/PGA ≥ 1.2 where T
i
are periods at which
the spectral accelerations SA are defined (using user-
defined damping level);
32 Issue C
T
m
=
∑
i
C
i
2
 1/ f
i

∑
i
C
i
2
T
0
=
∑
i
T
i
ln
[ SA T
i

PGA
]
∑
i
ln
[ SA T
i

PGA
]