Dynamic Response of a Long-Span Suspension Bridge During an Offshore Earthquake

Structural Health Monitoring (SHM) has been widely recognized in engineering research since the rapid advancement in sensor and data acquisition technologies over the last two decades. Additionally, owing to the immense infrastructure development around the world, utilizing a proper SHM system for large-scale bridges became essential because of their operation security and reliability issues. In this regard, this paper delves into the use of SHM for evaluating the seismic response of a long-span suspension bridge in the Marmara Region, Turkiye. Data obtained from the Fatih Sultan Mehmet (FSM) Bridge during the Silivri Earthquake (Mw 5.8) on 26th September 2019 was analyzed using response spectrum techniques. A comparative study was conducted to explore the FSM Bridge's dynamic response during this seismic event. This study also involved a comparison of the elastic design spectra of the First Bosphorus Bridge and the FSM Bridge with the response spectra of two extreme earthquake events (Mw 7.4, Kocaeli and Mw 7.2, Düzce earthquakes) recorded in the region. The analyses were performed for both near and far fault scenarios. The results demonstrated that the response spectrum for each selected far fault earthquake was below the design spectra curves for DD-1, as per the Turkish Earthquake Code (TEC-2018), which represents the maximum expected earthquake ground motion level. In conclusion, it is envisaged that the results will provide valuable knowledge to users for understanding similar types of long-span suspension bridge responses under moderate and extreme events.