Dynamic System Properties from Real-Scale Free-Vibration Soil-Structure Interaction Experiments
Dimitris Pitilakis1, Athanasios Vratsikidis2
1 Assistant Professor, Department of Civil Engineering
Aristotle University of Thessaloniki
dpitilakis@civil.auth.gr
2 Department of Civil Engineering
Aristotle University of Thessaloniki
avratsik@civil.auth.gr
Abstract. In this paper we present the results of free-vibration soil-foundation-structure experiments performed on the large-scale structure of EuroProteas, a real-scale prototype structure located in the experimental facility of Euroseistest in Northern Greece. Europroteas is a particularly simple stiff structure founded on soft soil and was especially designed to mobilize strong soil-structure interaction (SSI) taking into account the well-known foundation soil at site. Pull-out tests were performed using a wire rope mounted on a counterweight. The tension forces applied on the wire rope were in a range between 2kN and 15kN. In total, more than 25 pull-out experiments were performed. Response was recorded by a dense 3D array composed of more than 80 instruments (accelerometers, seismometers, shape-accelerations-arrays). Recorded response from selected tests is presented here. Experimental data from a wide range of free-vibration tests were used to calculate the damping ratio of the system. The results showed that the structure is subjected to strong SSI effects. For low pull-out forces the calculated damping ratio was in agreement with the system identification analysis performed in previous studies. On the other hand, for large pull-out forces soil nonlinearities were produced affecting the results.
Keywords: free vibration, soil-foundation-structure interaction, field test, large-scale experiment, damping
