Guralp Systems ART User Manual
Page 30
ART
16. absolute significant (effective) duration in seconds,
which is the interval between the Arias intensity
exceeding an absolute threshold specified in the
‘Options’ window (‘Significant Absolute (Begin)’) and
the Arias intensity exceeding the total Arias intensity
minus another threshold specified in the ‘Options’
window (‘Significant Absolute (End)’) (Bommer &
Martinez-Pereira, 1999).
For example, if the thresholds are given as 0.1 and
0.125ms
-1
then the duration is given as the interval
between the Arias intensity exceeding for the first
time 0.1ms
-1
to the total Arias intensity (e.g 0.5)
minus 0.125ms
-1
(e.g. 0.375);
17. relative significant duration in seconds, which is the
interval between the proportion of Arias intensity
exceeding that specified in the ‘Options’ window
(‘Significant Relative (Begin)’) and the proportion of
Arias intensity exceeding that specified in the
‘Options’ window (‘Significant Relative (End)’).
18. response spectrum intensity (SI) in selected
displacement units calculated from
with the limits specified in ‘Options’ window, where
PSV(5%,T) is pseudo-spectral velocity for 5% damping
and T is natural period [see Kramer (1996, p. 83)]
(note that this parameter is only calculated if the
response spectrum of the time-history has already
been calculated. The response spectra calculation
must be run again if the limits given in the ‘Options’
window are changed after the response spectra
calculation was made);
19. acceleration spectrum intensity (ASI) in selected
velocity units calculated from
with the limits specified in ‘Options’ window, where
SA(5%,T) is spectral acceleration for 5% damping and
T is natural period [see Kramer (1996, p. 83)] (note
that this parameter is only calculated if the response
spectrum of the time-history has already been
30
Issue C
SI =
∫
PSV 5% ,T dT
ASI =
∫
SA 5% , dT