This study was undertaken to address new developments in IEEE P693/D16 [IEEE693 WG 2017], account for the new strong-motion records from the recent major earthquakes, and assess their effects on the spectral demand. A large set of both crustal and subduction type records was investigated based on a number of parameters and intensity measures. The best candidates were selected as seed motions. The motions were matched to the IEEE693 spectrum in a time domain at 5% damping, which follows the guidance of IEEE P693/D16 [IEEE693 WG 2017]. In addition, three three-component synthetic time histories were generated. All modified and generated time histories were arranged into a suite of time histories proposed for use in IEEE693 seismic qualification analysis and testing. The suite consisted of four IEEE693-spectrum-compatible time histories modified from crustal records, one IEEE693-spectrum-compatible time history modified from a subduction record, and three IEEE693-spectrum-compatible synthetic time histories. The spectral matching was conducted with a tight tolerance to remain within a 15% strip above the IEEE693 spectra in a wide-frequency range. It was shown that the conservatism of the IEEE693 spectrum is different for crustal and subduction type records. Based on the results of the investigation, the study summarizes the basis for changes to the requirements for development of input time histories given in IEEE P693/D16, and considerations for input motion specifications for a future edition of the standard.
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