Proposal of Design Energy Equivalent Velocity Spectrum Using Long-Period Ground Motion Records of Magnitude 7 to 7.5 Earthquakes

Typically, the duration of strong motion in long-period ground motions is longer than that of short-period ground motions. This is because long-period ground motions are primarily caused by large-scale earthquakes. When the duration of strong motion increases, the energy input to a building may increase. However, the acceleration response spectrum used in seismic design does not consider the duration of strong motion. On the contrary, the energy equivalent velocity ( $${V}_{E}$$ ) spectrum can consider the duration of strong motion as $${V}_{E}$$ represents the total energy input to a building. This paper proposes a design spectrum using long-period ground motions generated by large-scale earthquakes (7–7.5 magnitude). The proposed design spectrum includes acceleration, velocity, and $${V}_{E}$$ spectrum. This study considered 22 large-scale earthquakes that occurred in the seismic zone of Japanese archipelago. Herein, the long-period ground motion refers to the ground motion with $${T}_{g}$$ (predominant period of acceleration response spectrum) of 1 s or longer. This is in consideration of the fact that the $${T}_{S}$$ (natural period at which acceleration response spectrum begins to decrease) of design spectrum proposed in previous studies is 1 s or less. The $${T}_{S}$$ of the seismic design code (KDS 41 17 00) is approximately 0.3 s < $${T}_{S}$$ <0.83 s. The acceleration and velocity spectrum of long-period ground motions are proposed using a line enveloping 84th percentile of the normalized response spectrum. The $${V}_{E}$$ spectrum of long-period ground motion is proposed based on the $${V}_{E}$$ – $${S}_{V}$$ relationship and the $${V}_{E}$$ spectrum of previous studies.