## 3 Seismic Shaking Table Tests
### Test Matrix  
Table 4 presents the summary of the test matrix carried out in this shaking table test. As shown in the table, three sets of the test mockup (OPT-2A, OPT-2B, and OPT-2C), which can validate the reliability for the consistency of LRB fabrication quality, are prepared to investigate the seismic isolation characteristics and performance. Each set is composed of four LRBs with the same dummy mass.  
As shown in the test matrix, four PGA levels of a seismic input motion such as 0.1 g, 0.3 g, 0.5 g, and 0.6 g are considered to be tested. In these load levels, 0.1 g and 0.3 g are the levels of the operating basis earthquake (OBE) and the safe shutdown earthquake (SSE) respectively. Moreover, 0.5 g is the level of the beyond design basis earthquake (BDBE) corresponding to the required seismic fragility capacity for 0.3 g SSE. The level of PGA = 0.6 g is the seismic fragility capacity corresponding to 0.36 g SSE level and is set to investigate the ultimate behavior of LRBs, which may occur in the seismically  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Test Mockup ID** & **Test ID** & **PGA (g)** & \multicolumn{2}{c}{**PGA with**} & \multicolumn{1}{c}{**Remarks**} \\  & & & **IEAF (F\({}_{\mu}\)) 1 (g)** & \multicolumn{1}{c}{**Remarks**} \\ \hline \multirow{4}{*}{OPT-2A} & OPT-2A-1 & 0.5 & 0.625 & Seismic Fragility \\  & OPT-2A-2 & 0.3 & 0.3 & SSE \\  & OPT-2A-3 & 0.1 & 0.1 & OBE \\ \hline \multirow{4}{*}{OPT-2B} & OPT-2B-1 & 0.5 & 0.625 & Seismic Fragility \\  & OPT-2B-2 & 0.3 & 0.3 & SSE \\  & OPT-2B-3 & 0.1 & 0.1 & OBE \\ \hline \multirow{2}{*}{OBT-2C} & OPT-2C-1 & 0.3 & 0.3 & SSE \\  & OPT-2C-2 & 0.6 & 0.75 & For Ultimate Behavior \\ \hline \hline \end{tabular}  
* \({}^{1}\) F\({}_{\mu}\) = 1.25: Inelastic energy absorption factor (IEAF) for building structure [24].  
\end{table}
Table 4: Test Matrix.  
Figure 4: Design response spectrum used in tests (PGA = 0.3 g).  
isolated nuclear facility components located at the 137 ft elevation level of the nuclear building structures.  
In the test mockups of OPT-2A and OPT-2B, the shaking table tests are sequentially carried out from 0.5 g level to 0.1 g. The purpose of this test plan is to investigate whether the seismic isolation performance can be achieved even when the smaller earthquakes occur continuously in the deformed state of the inserted lead plug after experiencing a large earthquake history. This test plan is also reasonable when considering that the primary purpose of developing the lead inserted small-sized LRB is to accommodate the beyond design basis earthquakes in the nuclear facility components. The tests for 0.3 g and 0.1 g after the 0.5 g test are set to investigate the LRB performance for aftershocks.  
All input motions corresponding to each PGA level were obtained by linearly scaling for the input motion of PGA = 0.3 g presented in Figure 3. When considering an actual earthquake event, the PGA levels above 0.3 g of SSE in the test matrix will be greater than linearly scaled levels because the design floor response spectrum used for the shaking table tests will be practically reduced due to the plastic behavior of the building structures, which can be represented by the inelastic energy absorption factor (IEAF). When taking the IEAF to be 1.25 as recommended in EPRI/NP-6041-SL [24], the PGA levels for 0.5 g and 0.6 g can be treated as 0.625 g and 0.75 g levels, respectively.  
All tests are carried out with an interim time of about 10 min after each test listed in test ID to minimize the variation of the rubber characteristics due to the temperature increase that may occur in the rubber in the test performed just before.