Significant experimental dynamic tests by vibrodyne were conducted on single piers of a motorway near Livomo (Italy). Tests were conducted on structures similar to each other but founded on two different type of soils (under consolidated silts below the water table and over consolidated clays) and very different dynamic responses were found in terms of damping and natural frequencies. This effect was particularly evident for single piles proving the importance of soil characteristics upon the dynamic response of the structure. It is refere also a numerical investigation about the behavior of identical structures founded on different soils and subjected to the same seismic input
