Seite - 1187 - in Book of Full Papers - Symposium Hydro Engineering

Fig. 1 Monitoring and modelling the dynamic behavior of large arch dams. 2. MONITORING THE DYNAMIC BEHAVIOR OF LARGE DAMS For large concrete dams, the installation of systems for continuous vibrations monitoring aims to measure and analyze acceleration records in several points in the dam and in the foundation, for different ambient/operational excitation and earthquakes of different magnitudes, based on the latest data acquisition technologies. The data measurements should be performed in as many points as possible, in order to obtain reliable modal identification results. Nonetheless, the efficiency and accuracy of these monitoring systems also depend heavily on the use of sophisticated software for analysis and management of the collected data. Therefore, it is of the utmost importance to develop and include computational tools, adapted to each dam, for automatic and/or interactive analysis [1,2], aiming to: a) identify the dam’s main modal parameters (natural frequencies, mode shapes and modal damping), based on frequency domain and/or time domain modal identification methods [4], and study their evolution over time, considering the water level and seasonal thermal variations, or to detect possible structural changes due to deterioration processes [5]; b) measure the dam dynamic response for different reservoir levels, enabling to evaluate the amplification of the accelerations recorded in the foundation and in the dam [6], as well as to study the influence of the dam-reservoir interaction. Furthermore, the developed software should enable the comparison between the monitored dam dynamic response and its dynamic behavior as predicted with the numerical programs: this is of great value to validate and calibrate the numerical models, which are used to simulate the dynamic behavior of DRF systems and to carry out seismic safety verifications. Monitoring Modelling Hardware Modal identification software 1187