The RIVAS FINAL CONFERENCE
“Vibration – Ways out of the annoyance”, was held in Brussels, on 21 November 2013
Please find here more information.
Noise and vibration have been identified as major challenges for the European railway system during a time when the railway sector is constantly increasing its transport volume. Shifting more transport to rail and increasing the market share of the sector can only be achieved with sustainable noise and vibration mitigation measures. This affects on the one hand the infrastructure and on the other hand the rolling stock which causes the vibration by the rail / wheel interaction.
RIVAS is a joint research and development project carried out by 27 partners from nine European countries within the 7th European Framework Programme.
RIVAS aims at reducing the environmental impact of ground-borne vibration from rail traffic while safeguarding the commercial competitiveness of the railway sector. For several areas of concern, vibration should be reduced to the threshold of annoyance or even below. The project's goal is therefore to provide tools to solve vibration problems for surface lines by 2013.
It therefore aims to contribute to the development of relevant and leading technologies for efficient control of people's exposure to vibration and vibration-induced noise caused by rail traffic.
RIVAS includes fundamental research, prototype construction, optimisation of pre-existing solutions and field testing under realistic conditions.
Ground vibration from railway traffic is generated either by the static axle loads moving along the track or by the dynamic forces arising from wheel and track irregularities. The influence of vehicle parameters like e.g. wheel set mass, axle distances, and properties of primary and secondary suspension has been quantified in a combination of state-of-the-art numerical modelling using train-track-soil models and the analysis of measurements. A similar research has been done to study the influence of wheel defects (most notably wheel flats and wheel polygonalisation) and of track irregularities. As the transmission of vibrations to receiver locations and also the performance of vibration mitigation measures strongly depend on the soil conditions, existing sites have been chosen as reference, where soil conditions are well known. These are located in Germany, Belgium and Sweden. Design studies and numerical modelling of the influencing parameters are performed within RIVAS such that they finally predict vibration levels at hypothetical receiver locations at the reference sites in order to ensure maximum comparability. Vibration reduction strategies based on optimized vehicle design and optimized maintenance of both wheel and track have been worked out and tested.
Low vibration track design requires reducing the global stiffness of the track. Parametric studies have been performed using coupled Finite Element/Boundary Element models both for ballasted track and for slab track. Various modifications of the rail-sleeper interface as well as of the sleeper-ballast interface (sleeper-slab interface in the case of slab track) have been simulated taking into account different types of soil and of rolling stock with the overall target of vibration reduction. Designs of wide sleepers in combination with soft under sleeper pads and of rail fastening systems with soft under rail pads have been proposed as being the most promising solutions. Corresponding systems were tested in laboratory. In the last phase field tests were performed. Solutions especially dedicated to reducing vibrations emitted from curves and switches could be achieved.
Vibration reduction measures on the transmission path between track and receiver (analogue to noise barriers) are ideal candidates for retrofitting existing lines as their installation does not require closing the track. Within RIVAS several designs have been studied by computer simulation: soil stiffening and sheet pile walls close to the track, open trenches and trenches filled either with soft or stiff materials. Their effect has been predicted for the reference cases (see above) and for two sites, where installation and field testing could be performed within RIVAS. For the latter sites, design optimization has been performed for the relevant frequency range taking into account soil layering. The potential field test sites, which are located in Spain and Switzerland, have been characterized by geotechnical tests.
The RIVAS Final Conference, which was held on 21st November 2013 in Brussels, provided a comprehensive overview of the RIVAS results.