A novel scalar ground motion intensity measure (IM), termed the energy‐frequency parameter, is proposed based on the Hilbert‐Huang transform. To validate the effectiveness of the proposed IM, the correlation analysis between the engineering demand parameter (EDP) and energy‐frequency parameter is performed using 1992 recorded ground motions, in which EDP is the maximum inter‐storey drift of structures obtained by nonlinear time‐history analysis. Results show that the energy‐frequency parameter has a strong linear correlation with EDP at natural logarithm, and this correlation is applicable for various structural fundamental periods. We also verified that the lognormal cumulative distribution function can characterize the energy‐frequency parameter‐based fragility function, which can further facilitate the application of the parameter in seismic risk analysis. Besides, the strong correlation between the energy‐frequency parameter and other IMs (such as PGA, PGV, PGD, CAV, , , and SI) potentially makes the proposed IM widely applicable in seismic risk analysis. Moreover, since the energy‐frequency parameter depends only on the frequency‐domain characteristics of the ground‐motion signal, it may closely link to seismological theory and provide new insights into seismology engineering.

Near‐fault pulse‐like ground motion is a significant class of seismic records since it tends to cause more severe damage to structures than ordinary ground motions. However, previous researches mainly focus on single‐pulse ground motions. The multipulse ground motions that exist in records receive rare attention. In this study, an analysis procedure is proposed to investigate the effect of multipulse ground motions on structures by integrating finite element analysis and an identification method that features each pulse in the multipulse ground motion satisfying the same evaluation criteria. First, the Arias intensity, wavelet‐based cumulative energy distribution, and response spectra of identified non‐, single‐, and multipulse ground motions are compared. Then, the seismic damage on frame structures, a soil slope, and a concrete dam under non‐, single‐, and multipulse ground motions are analyzed. Results show that the spectral velocity of multipulse ground motions is significantly greater than those of non‐ and single‐pulse ground motions and potentially contains multiple peaks in the long‐period range. Seismic damage evaluation indicates that the maximum interstory drift of frame structures with high fundamental periods under multipulse ground motions is about twice that of nonpulse ground motions. Similar characteristics also exist in the soil slope and the concrete dam. Therefore, multipulse ground motions potentially cause more severe damage to structures compared to non‐ and single‐pulse ground motions. The findings of this study facilitate the recognition of the increased seismic demand imposed by the multipulse ground motion in engineering practices, provide new possibilities for ground motion selection in seismic design validation, and shed new light on seismic hazard and risk analysis in near‐fault regions.