Page - 1188 - in Book of Full Papers - Symposium Hydro Engineering

3. CABRIL DAM. MONITORING SYSTEM: HARDWARE AND SOFTWARE Cabril dam was built in 1950’s and is the highest Portuguese arch dam (Fig. 2). Located in the Zêzere River, this is a 132 m high double curvature arch dam with crest altitude of 297 m. The arch is 290 m long at the top, and the central cantilever has a maximum width of 19 m at the base and a minimum width of 4.5 m below the crest. In this dam, a significant horizontal cracking phenomena occurred near the crest (at a height of 280-290 m) during the first filling of the reservoir. Also, a concrete swelling process has been detected in recent years. In the framework of LNEC research activities regarding monitoring and modelling the dynamic behavior of dams, a pioneer project was initiated in 2002 [1] to install a dynamic monitoring system in Cabril dam, which is in operation since 2008 (Fig.2). The outlined configuration for this system was based on experience gathered in LNEC over the years, from both monitoring data and numerical results [2,3,5,6,7]. The goal was to implement a system with a high dynamic range, capable of a continuous accurate measurement of the dam’s response for several dynamic excitations: ambient/operation excitations or earthquakes of various magnitudes. This system was designed to measure accelerations in the upper zone of the dam and near the base, at a sampling rate of 1000 Hz and considering time periods of one hour, and it includes 16 uniaxial and 3 triaxial accelerometers. Fig. 3 Cabril dam. Plan and central cantilever (with intake tower) and vibrations monitoring system - schematic representation and main hardware components. RB Control center (dam) VPN Analysis center LNECInternet ontrol center (da ) nalysis center L ECI t r t Control center (dam) VPN Analysis center LNECInternet Control center (dam) LB Switch optical-electric Optical fibre (ring net) Control center (dam) VPN Analysis center LNECInternet Data concentrators OCS (dam) Analysis centre (LNEC) Remote control Triaxial accelerometers (3) Uniaxial accelerometers in radial direction (16) Vibrations monitoring system Cabril dam 1188