Experimental study on seismic responses of tuned mass damper-applied real-scale piping system via shaking table tests

To secure the nuclear power plant (NPP) safety, it is essential to improve the seismic performance of piping systems. Accordingly, to achieve this purpose effectively, applying a tuned mass damper (TMD) to the NPP piping system has been attempted, but this is mostly limited to numerical analysis studies. Therefore, this study aimed to prove the TMD effect of reducing seismic responses of the real-scale NPP piping system through shaking table tests. As a result, it was confirmed that the TMD suppressed target and higher-order mode responses of the piping through the shaking table tests. In particular, the response control effects of the target mode and the higher-order mode were more pronounced when the earthquake motion intensity was larger. The application of the TMD showed reducing relative displacement responses in the harmonic motion excitation by about 80%-90%. This reduced peak relative displacement and normal stress responses by 33%-42% and 25%-37% on average, respectively, under random vibration excitation. Under the seismic excitation, peak relative displacement and normal stress responses were reduced by 7%-14% and 5%-27% on average, respectively. Finally, piping and piping-TMD finite element analysis models were successfully created and validated based on the shaking table test results.