Evaluation of intensity measure performance in regional seismic risk assessment of reinforced concrete bridge inventories

Abstract

Seismic risk assessment requires fragility functions derived using non-linear time-history analysis with earthquake records compatible with the site hazard and characterised via a suitable intensity measure (IM), which poses a challenge given the wide variety of structural characteristics found in bridge inventories. Given the lack of consensus on a suitable IM, regional studies often use peak ground acceleration (PGA), which despite being recognized as a poor indicator of structural performance, has persisted in earthquake response characterisation. Average spectral acceleration (AvgSa) has recently gained popularity since it describes earthquake intensity over a range of pertinent periods of vibration; however, its suitability as an IM has not been demonstrated on real bridge inventories with a wide variety of structural characteristics. In this study, hazard-consistent records selected for both PGA and AvgSa are used to evaluate the response of a large inventory of existing bridges with varying structural characteristics, from the Italian roadway network. The results indicate that AvgSa is a more accurate IM compared to PGA when applied to the regional assessment of RC bridges.

Keywords:

• Regional seismic risk
• bridges
• intensity measure
• average spectral acceleration
• ground motion record selection
• road network
• infrastructure assessment

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work presented in this paper has been developed within the framework of the project “Dipartimenti di Eccellenza”, funded by the Italian Ministry of Education, University and Research at IUSS Pavia. It has also received support from the INFRA-NAT project co-funded by European Commission ECHO – Humanitarian Aid and Civil Protection. Project reference: 783298 – INFRA-NAT – UCPM-2017-PP-AG.