Measurements of Vibrations and computer simulations in the design of vibroinsulation of railroads

Abstract

Presented paper describes the problem of vibrations in buildings generated by rail transport. The dynamic analysis presented in this paper was based on two Polish standards developed at the Institute of the Structural Mechanics at the Cracow University of Technology: PN-2016/B-02170. Evaluation of the harmfulness of building vibrations due to ground motion and PN-2017/B-02171. Evaluation of vibration influence on people in buildings. These standards define the rules, methods and criteria of the performed evaluations. A prepared computational model of the building, as well as the way of propagation of vibrations generated by trains or trams, often requires experimental verification. It could be done due to measurements. The results of field tests should be recorded in the databases containing information related to the geometry of the structure (building itself, track bed and tunnel-housing in case of the metro), propagation path (its length and nature of soil layers) and finally material properties. Presented examples of computer simulation application during designing of the vibration isolation of railway tracks in the tunnel as well as tram line surface, showed that the basis of such calculations should be carried out by vibration measurements in a given case or taken from proper measurement databases. Predictions may concern not only the impact of vibrations on surrounding buildings and people staying in them, but also reduction of expected vibrations of the engineering structures. In order to verify the correctness of adopted due to computer simulations solutions minimizing vibrations, it is necessary to perform post-implementation measurements, which should be a supplement to the mentioned database. This approach to the design of vibroisolation allows checking the used numerical procedures as well as implemented material constants describing materials used in the numerical model or in the case of constructing the building the quality of the materials used.