Pedro Alves Costa, Assistant Professor – University of Porto
Prediction and mitigation of railway vibrations. Potentialities and challenges of numerical modelling
The growing of world population and its concentration on urban centres is raising new challenges and demands to society and, consequently to engineering. Accordingly to UN, the population living in metropolitan areas will reach 66% of the world population around 2050. This abrupt population growth in urban areas will bring new demands in several engineering topics, namely at the development of efficient and eco-friendly transportation systems, where railway systems (at surface or underground) play a relevant role. Despite of the advantages provided by railway systems, there are also some drawbacks, like vibration and noise inside buildings due to traffic.
This is a specific aspect that deserves comprehensive research and transfer of knowledge from academia to engineering practice. In this context, the numerical modelling can give an interesting support on the prediction of vibrations induced by traffic and also on the design of mitigation countermeasures. The presentation focuses on the challenges and possibilities provided by numerical modelling on the prediction and mitigation of vibrations induced by railway traffic. Once very large domains need to be considered, the potentialities of 2.5D approaches for dealing with the problem are discussed. Moreover, the ability of this kind of models for dealing efficiently with the train-track-ground-building dynamic interactions is highlighted.
After the discussion about the modelling strategies, their ability for dealing with real situations is evaluated through the comparison between predicted and measured results. After the experimental validation of the numerical models, their potentialities on the design of mitigation measures are explored. Two distinct mitigation measures are analysed:
- at source (ballast mats or floating slab solutions);
- at path (trench and barriers installed on the ground).
A comprehensive discussion about the efficiency of this kind of solutions is performed, with focus on the potential impact that can be achieved on the vibration levels inside buildings close to the railway infrastructures.