The Role of Soil-Structure Interaction in the Interpretation of Dynamic Tests on the “Chiaravalle viaduct”

The paper addresses the significance of soil-structure interaction on the dynamic behaviour of the “Chiaravalle viaduct”, based on ambient vibration measurements and numerical simula-tions. The viaduct is located in Central Italy and is founded on piles in an eluvial-colluvial soil deposit. Experimental modal properties are evaluated by means of the operational modal anal-ysis on accelerometric data from ambient excitation and the role of soil-structure interaction in the interpretation of tests is investigated by means of a refined finite element model of the via-duct. In the soil-structure interaction models the local site condition in correspondence of each bridge piers (resulting from geotechnical and geophysical investigations) are considered in the definition of the soil-foundations compliance. Comparison between the experimental and nu-merical results highlight the role of the pile-soil-pile interaction, the radiation problem, the pile cap embedment and the variability of the soil stratigraphy along the longitudinal direction of the viaduct in the interpretation of the experimental data.