Analysis of modal properties of two nominaly identical turbine supporting structures

The paper presents study of modal parameters identification of two turbine supporting structures of unit-A1 and unit-A2 in Power Plant Nikola Tesla – A in Obrenovac – Republic of Serbia, based on ambient vibration measurements. Vibration response measurements of structures were carried out in two measurement campaigns under ambient excitation, each time on unit which was out of operation. Modal frequencies and mode shapes were extracted using Frequency Domain Decomposition (FDD) technique according to recorded acceleration data. The performed numerical analysis established the dynamic characteristics of the analysed table-top foundation structure adequate to the experimentally determined ones