# Study on Seismic Performance of a Mold Transformer through Shaking Table Tests
## 2 Experimental Program
### Input and Testing Protocol  
In this study, tri-axial accelerations were generated according to the ICC-ES AC156 code [14]. The input acceleration-time history was artificially generated to match the required response spectrum (RRS) specified by the AC156 code for non-structural components that have fundamental frequencies in the range of 1.3-33.3 Hz. Figure 5 shows that for horizontal RRS, the horizontal spectral acceleration for flexible components, \(A_{FLX\text{-}H}\), and horizontal spectral acceleration for rigid components \(A_{RIG\text{-}H}\), were determined as:  
\[A_{FLX\text{-}H}=S_{DS}\bigg{(}1+2\frac{z}{h}\bigg{)}\leq 1.6S_{DS}, \tag{1}\]  
\[A_{RIG\text{-}H}=0.4S_{DS}\bigg{(}1+2\frac{z}{h}\bigg{)}, \tag{2}\]  
\[S_{DS}=\frac{2}{3}\cdot F_{A}\cdot S_{S}, \tag{3}\]  
where \(S_{DS}\) is the site-specific ground spectral acceleration factor, defined according to the Korea Building Code [16], (\(S_{DS}=0.498\) in this study); \(z\) and \(h\) are the height of the component's attachment point to the structure and the average height of the building roof with respect to the base, respectively; \(F_{A}\) is the site soil coefficient; and \(S_{S}\) is the mapped maximum considered earthquake spectral acceleration at a short period. In the current study, the ratio \(z/h\) was equal to 0, with the assumption that the mold transformer was located at the base of the structure. Figure 4: Photograph of the shaking table system used in this study. Regarding vertical RRS, the vertical spectral acceleration for flexible components, \(A_{FLX\cdot V}\), and vertical spectral acceleration for rigid components, \(A_{RIG\cdot V}\), were determined as [14]:  
\[A_{FLX-V}=0.67A_{FLX-H}, \tag{4}\]  
\[A_{RIG-V}=0.27A_{RIG-H}. \tag{5}\]  
Moreover, according to the specifications in ICC-ES AC156 [14] and Eurocode 8 [17], the elastic acceleration spectrum acquired from the selected artificial acceleration time history shall be in a range of 90-130% of RRS, and the matching procedure shall be validated for a range of frequency from 1.3 to 33.3 Hz. Table 3 summarizes the test program in this study. The test nos. 4-7, 11-14, 18, and 19 are the primary tests. The initial input acceleration time histories in the X, Y, and Z-directions of test no. 7 were artificially generated based on the AC156 code using Equations (1)-(5) and denoted as AC156_100. In the test nos. 4-6, 11-14, 18, and 19, the acceleration magnitudes were scaled from AC156_100 using different scaling factors in the range of 25-300%, corresponding to \(S_{DS}\) in the range of 0.12-1.49\(\times\)_g_, and denoted as AC156_25 to AC156_300. Figure 6 shows the acceleration time history in the X and Y-directions of AC156_100 used in test no. 7, whereas Figure 7 shows the comparison between the result of the input spectrum of AC156_100 in the X and Y-directions for a damping ratio of 5% and the AC156 target spectrum, as well as its limited boundaries. As shown in the figure, the AC156_100 input spectrum is in a range with a lower limit of 90% RRS and an upper limit of 130% RRS. Table 3 also summarizes the input peak ground accelerations (PGA) of the primary tests corresponding to the scaling factors for each test. Figure 5: Require response spectrum (AC156 code). Figure 6: Input acceleration time history in the X and Y-directions for AC156_100. Along with the primary tests, the intermediate tests (test nos. 1-3, 8-10, 15-17, and 20-22) were carried out for dynamic identification of the test specimen. Such tests were performed in the X, Y, and Z-directions by applying low-amplitude random input signals with the frequency domain in the range of 1-50 Hz, according to FEMA 461 [15]. To be more specific, test nos. 1-3 were carried out before the AC156_25 (test no. 4) in the X, Y, and Z-direction, respectively; test nos. 8-10 were carried out after the AC156_100 (test no. 7) in the X, Y, and Z-direction, respectively; test nos. 15-17 were carried out after the AC156_200 (test no. 14) in the X, Y, and Z-direction, respectively; and test nos.