Duration Effects of Near-Fault Ground Motions on Structural Seismic Responses

This study reveals the duration effects of near-fault ground motions with distinct long-period pulse and without pulse on structural seismic responses and damage. To this end, several velocity-based duration measures (DMs) are proposed according to the characteristic of abundant low-frequency content in near-fault records, and non-structural compound intensity measures (IMs) incorporating DMs are suggested. Moreover, the correlations between the IMs and DMs of near-fault ground motions, as well as those between the IMs and DMs of ground motions and the seismic responses (i.e. maximum displacement D-max, input energy E-I and hysteretic energy E-H) of bilinear single-degree-of-freedom (SDOF) systems, are scrutinized. It is shown that the acceleration-based absolute uniform durations present strong correlation with the acceleration-related IMs, while the velocity-based absolute uniform durations highly correlate with the velocity- and displacement-related IMs. In the short-period region, the acceleration-based absolute uniform duration U-0.10 g is well correlated with the seismic responses, while in the medium-, medium-long- and long-period regions, the velocity-based absolute uniform duration U-v10 exhibits strong correlation. Additionally, the compound IMs combining with uniform durations (PGA center dot U-0.10 g and PGV center dot U-v10) are the competent indices to quantify duration effects of near-fault records. The similar observations for duration effects are validated by four representative frame buildings considering Bouc-Wen hysteretic behavior without or with degradation of strength and stiffness.

Automated summary

This study investigates the duration effects of near-fault ground motions on structural seismic responses and damage. The researchers propose velocity-based duration measures and suggest non-structural compound intensity measures incorporating these duration measures. The correlations between the intensity measures and duration measures, as well as their correlations with seismic responses, are examined. The study demonstrates that the acceleration-based absolute uniform durations have a strong correlation with acceleration-related intensity measures, while the velocity-based absolute uniform durations highly correlate with velocity- and displacement-related intensity measures.