Rapid Post-Earthquake Estimation of Vibration Frequencies of Historical Masonry Structures Using Laser Doppler Vibrometry

Abstract

It is challenging to conduct operational modal analysis of structures using contact sensors (e.g. accelerometers) in post-earthquake reconnaissance studies due to safety concerns. This paper presents the use of Laser Doppler Vibrometry as a safe and practical non-contact alternative to detect vibration frequencies of historical masonry structures. A single point Laser Doppler Vibrometer (LDV) was used to collect ambient vibration data from historical masonry structures after the 2023 Kahramanmaras earthquakes. The velocity measurements for a single-span arch bridge and a historic church are analysed in the frequency domain to identify the vibration modes of the examined structures. The vibration frequencies are used to evaluate, and where necessary update, the 3D finite element models created from point cloud data and non-destructive material tests. The results highlight the potential of LDV to provide practically useful data for conducting forensic post-earthquake investigations.

Keywords

• Historic masonry
• laser Doppler vibrometry
• model calibration
• natural frequency

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