DYNAMIC CHARACTERISTICS OF ANCIENT STONE ARCH BRIDGES

The aim of this paper is to investigate the dynamic characteristics of ancient stone bridges in Korea and to find the factors influencing their natural frequencies. For this end, on-site free vibration tests were performed for 18 stone arch bridges and one ancient ice storage composed of 4 arches. Test results revealed that the vertical fundamental frequencies were in the range of 10Hz to 45Hz. The damping ratios estimated from the records of free vibration tests showed a wide variety of values, that is, from 0.02 to 0.134. It has been known that the natural frequencies of stone arch bridges are mainly governed by their arch spans. Test results reveal that the presence of spandrel walls and the use of mortar for joints are also important factors influencing the natural frequencies of stone arch bridges.