IDENTIFICATION OF DYNAMIC CHARACTERISTICS OF AN EXISTING ARCH DAM BASED ON AMBIENT VIBRATION OBSERVATION AND THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS

Abstract

 Earthquake and ambient vibration monitoring of the crest of an aged arch dam was carried out. Long-term continuous monitoring was conducted to determine the change in natural frequency over time by installing accelerometers at two locations on the crest. On the other hand, short-term ambient vibration monitoring was also conducted to evaluate the dynamic characteristics of the entire arch dam system, such as the natural frequencies, modal dampings and mode shapes, by installing an array of sensors. This paper presents the Young's modulus of the dam body concrete and foundational bedrock with a small amplitude, based on data from the short-term monitoring, as well as three-dimensional finite element analysis. The results would enable further investigation of the relationship among the natural frequency, reservoir level and body temperature of the dam based on data from the long-term monitoring as a bench mark.