Compared to other bridges (roadway or pedestrian), railway bridges need specific analysis due to their peculiarities: heavy bulks in transit (trains) and on the infrastructure (ballasts and railway equipment), speed of trains, fixed loaded axles (rails), great interactions between trains and structure.
Degradation is manly caused by chemical processes affecting steel (corrosion) and concrete (alkali-aggregate reaction).
The Railway BriViDi (Bridge Vibration Diagnostics) research project aims at developing an integrated methodology to evaluate structural integrity of railway bridges, in order to ensure their reliability and safety.
The methodology aims at being:
- Applicable during the operations (without stopping railway traffic);
- Suitable for testing several type of bridges under different operating conditions (high speed trains, passenger trains and freight trains)
- Usable data (collected by industrial instruments)
- Sound and reliable methodology.
The research work was subdivided in three activities:
- Testing of beams according to typical degradation schemes, to mechanical stress and constraints of railway bridges;
- Identification of dynamic properties of data through advanced techniques;
- Modelling of degraded beams.
The main results were:
- the definition of a methodology for the identification of dynamic characteristics of degraded beams;
- the provision of numerical and physical models of degraded beams;
- the results from laboratory tests.