AMPLITUDE DEPENDENCE IN THE VIBRATIONAL CHARACTERISTICS OF FULL-SCALE VIADUCTS

Abstract

 The vibrational characteristics of railway viaducts, including natural frequencies and damping ratios, are crucial for understanding their seismic behavior. These characteristics are known to exhibit amplitude dependence, varying with the magnitude of oscillation. In this study, a full-scale facility consisting of three viaducts was utilized. Multiple accelerometers were strategically placed for continuous micro-vibration monitoring and seismic observation. Through organizing the measurement results, we estimated the vibrational properties and mode shapes of the viaducts. Additionally, we confirmed the amplitude dependence. The findings revealed that the viaduct vibrates as a unified structure in the direction of the railway tracks. In the perpendicular direction to the tracks, the terminal and starting ends exhibit significant vibrations, maintaining consistency from micro-vibrations to seismic motions. On the other hand, as the input amplitude increases, the natural frequencies tend to lengthen, and damping increases.