Scaling ground motion records by considering the inelastic response of soils

Abstract

One of the main shortcomings of several seismic databases is the lack of ground motion records exhibiting high-intensity values. Consequently, when characterizing seismic risk, or in the design process of a civil infrastructure, it is generally necessary to scale up a significant amount of low-intensity records so that the nonlinear response of the analyzed system can be fully explored. However, this type of records does not reflect neither the stiffness degradation nor the increasing of damping in soils affected by high-intensity ground motions. This paper presents an innovative approach for scaling seismic records by taking into account both effects. To do so, the equivalent linear method has been employed in an iterative manner to scale up and get records meeting these important conditions. A database from Colombia containing almost two thousand ground motion records has been used to characterize the seismic hazard. Results show that low-amplitude records scaled following the presented approach exhibit an increase of intensities at certain periods, which is consistent with the one observed in actual high-intensity ground motion records. In addition, the inelastic response of the soil tends to modify the expected risk, showing that scaling using constant values can produce biased results. It has been observed after comparing fragility functions derived for records scaled using a single scalar vs those considering the inelastic response of the soil.

This research has been funded by the Spanish Research Agency (AEI) of the Spanish Ministry of Science and Innovation (MICIN) through the projects with references: PID2020117374RB-I00/AEI/10.13039/501100011033 and TED2021-132559B-I00 – J-02970.

Peer Reviewed

Postprint (published version)