Pulse Identification

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Ground motions with significant velocity pulses are of particular importance to structural engineers because they can place greater demands on structures than non-pulse-like ground motions. The pulse calculation tool calculates up to 5 different pulses for a triplet and allows the user to select the most appropriate pulse. Once the desired pulse is selected, the user can plot the time histories and the spectra of 1)

•The pulse

•The record rotated to the pulse direction

•The residual

The pulse calculation is based on the algorithm presented in Shahi and Baker [33].

Results

After clicking the "Calculate Pulse" button, the results will appear in the view. The pulse columns are the following:

•is_pulse: "Yes" represents a pulse-like records and "No" indicates the record is not a pulse

•pulse_indication: reports pulse indicator. Pulse indicator is a predictor of the likelihood that a given record is pulse-like

•Tp: reports the pulse period

•wavelet_name: name of the wavelet used to determine pulse parameters

•pulse_scale: reports the pulse scale. Pulse scale is thee scale at which the largest wavelet was found

•PGV: peak ground velocity of the pulse-like record

•PGV_resid: peak ground velocity of the residual pulse-like record

•PulseAngle: reports the pulse angle

•PulseAz: reports the pulse azimuth

•Late: late is another criteria to reject records whose pulse score is positive since the pulse caused by directivity effects arrive early in the time-history

•Wavelet_coeff: report the wavelet coefficient

For the record to be classified a pulse-like record, it should have a positive pulse indicator and not be classified as "late".

The 5 pulses sorted in descending order based on the wavelet coefficient. In case of bulk calculation (compute ims and spectra dialog) the first pulse one of the 5 where is_pulse is Yes is automatically selected.

	Select Pulse
	If the record was found to be a pulse-like record, the user can click on the record and select the desired row. QuakeManager will populate the pulse parameter values in the record properties.

Figure: pulse record with pulse residual and pulse plus residual