Shaymaa Obayes, Monique Head

Abstract: While previous studies have explored bridge vulnerabilities, there is a notable gap in assessing the susceptibility of existing bridges, particularly slab bridges, to long-duration earthquakes in seismically active regions. This study uniquely quantifies and evaluates the impact of a moment magnitude (MW) 9.0 earthquake, characterized by its long duration, on the incipient collapse risk of slab bridges in the Pacific Northwest (PNW) region of the United States. The assessment includes potential flexural failures in slab bridge columns and the associated collapse risk. A slab bridge is modeled in OpenSees for case studies to determine vulnerability and incipient collapse risk through fragility analyses and a risk-targeted approach in accordance with the 2023 AASHTO Guide Specifications for LRFD Seismic Bridge Design. The study emphasizes the consequences of outdated seismic design standards, particularly for slab bridges constructed before the 1990s. Moreover, the findings reveal that long-duration earthquakes significantly increase the collapse risk of aging slab bridges built before the 1990s.

Keywords: Slab bridge, Pacific Northwest, Long-duration, Fragility analyses, Risk-targeted

Date Published: August 8, 2024
DOI: 10.11159/ijci.2024.011

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