This report concerns a real and actual problem of buildings affected by vibrations generated by various urban activities. The project focuses on the vibrations propagation through ground and investigates solutions to reduce the magnitude of these vibrations. In order to mitigate vibrations a relative new idea is studied by using masses placed in between the vibration source and the receiver which can be either placed on the ground surface or embedded in the ground.

The problem is studied from two different approaches, a small scale laboratory experiment and by numerical models. The research work starts with the task of scaling the vibrations characteristics to convenient laboratory dimensions while using accessible materials. Furthermore the behavior of the materials and of the test setup is investigated step by step using specialized equipment (accelerometers , impact hammer and a data processing software PULSE) in the format of a frequency response function (FRF) analysis. The investigation lead to a number of two final experimental test setups, each of them having the possibility to be adapted to a series of added masses configurations. The first model simulates a single soil layer with masses positioned on the surface between an exciter and a receiver. The second model resembles a thicker layer of soil with the masses embedded in the ground volume. Subsequently, using the commercial software Abaqus CAE a series of numerical models are modeled with the same boundary conditions and the same materials used in the experimental analysis. The results from the experimental and numerical analysis are then compared and the ability of the numerical models of simulating this phenomenon is tested.

It was discovered that the numerical model matches better relative simple models where less uncertainties are likely to be introduced. The effect of added masses could be observed in all test setups configurations for both experimental and numerical analyses. The response recorded attenuation of the accelerations at some frequency ranges but in the same time increased response could be observed at other frequencies. The most significant positive influence was observed when multiple masses were placed in between the exciter and receiver simulating a periodic configuration of the masses.