Experimental and Numerical Investigation on the Effectiveness of Polymeric Barriers to Mitigate Vibrations

The results of an experimental activity aimed at investigating the ability of barriers made of a soft polymer [Super Absorbing Polymer (SAP)] to reduce the impact of ground vibrations on existing structures are described in this paper. A series of field tests was performed to examine the screening effectiveness of such barriers. Perturbing shear waves were generated using a vibrant source with controlled force and frequency. Field measurements of wave propagation with and without the barrier show the reduction of amplitude in several points of interest, caused by the extremely low shear stiffness of SAP. Two different geometrical configurations of the barriers were adopted in the field: one having the classical vertical trench shape, and the other with a less common shape of an upside-down pyramid. A FEM model was built and numerical analyses were performed and validated against the experimental results. After validation, the numerical analyses were also used to add further information on the behaviour of barriers of different shape.