Structural Monitoring and Analysis
Metsovo Bridge Structural Monitoring System
Metsovo Bridge is a highway bridge in the course of the east-west connection “Egnatia Odos” in the north of Greece.
The 4-span, totally 540 m long prestressed concrete bridge traverses an approximately 120 m deep ravine and lies between two tunnel portals. The main span is given with 235 m. The deck is constructed to the balanced cantilever method. Both main piers are founded on shafts with diameters of 12 m and length up to 25 m. The design is governed mainly by the high seismic loads in this region.
The scope of the project was monitoring the structure with respect to ground motions and other ambient dynamic activity such as dynamic loads imposed by the traffic, environmental effects, etc.
The system is composed of two main sensor groups and the central acquisition computer. The first group measures the acceleration of the ground and vibrations of the bridge.
The accelerometers are placed on the basement of two main pylons and in the maintenance tunnel below the deck. The second group consists of strain gage sensor and displacement transducers. The displacement transducers are located at the end of the bridge at the conjunction point between the bridge and the ground, whereas the strain gauge sensors are positioned in different points along the bridge (see figure).
All measured data are acquired at the Central Recording Unit (CR-5P). The CR-5P integrates the digitiser board and an industrial PC in one platform, simply controlled through the Windows XP operating system. The measured data are managed by GeoSIG developed seismic software GeoDAS.
|4 x Accelerometers||Triaxial Force Balance Accelerometer||AC-63|
|14 x Strain Sensors||Uniaxial Strain Gage||GSG-xx|
|4 x Displacement Sensors||Displacement Transducer||GS-LVDT|
|1 x Meteorological Sensor||Wind Speed and Direction||METEO-WDST|
|1 x Central Recorder||Multichannel Recording system|
All the data are stored locally and accessible via the Remote Desktop available on all operating system (Windows, MacOS X and Linux). The Recording Unit sends SMS and e-mails alarms to selected user groups.