###### Abstract
Figure 1: Description of base frame deformation and rocking behavior of the cabinet. Figure 2: Earthquake damage to electrical cabinets [1; 28]. Most numerical models simplify anchorage boundary conditions by assuming rigid fixation to the foundation [20; 22]. However, the flexibility of the base frame significantly varies depending on weld quality, anchor bolt characteristics, specific mounting arrangements, and structural details, making it difficult to directly incorporate these factors into numerical models [24; 32; 33; 34]. In particular, constraining the vertical degree of freedom at the anchorage can result in deformation occurring below the foundation level due to cup-like deformation at the base frame (Figure 1). However, such downward displacement is physically restricted in actual behavior. The anchorage system exhibits nonlinear behavior, and inaccurate modeling of boundary conditions at the anchorage can result in erroneous predictions of seismic response [25]. Recent studies have found that simplified constraints on anchorage degrees of freedom may lead to overestimation of cabinet seismic performance, recommending the incorporation of the hysteretic behavior of anchor bolts to better represent cabinet-foundation interaction effects [27; 35]. Furthermore, studies reveal that modeling torque loosening induced by cabinet dynamics is limited in its effectiveness [36]. While numerical methods are more cost-effective than experimental approaches, their predictive accuracy is limited by the complexity of accurately modeling anchorage behavior. In addition, numerical studies based on shaking table test results often evaluate seismic behavior by validating only the natural frequencies and modal properties of numerical models, or by considering only unidirectional or horizontal seismic motions [12; 20]. At relatively low seismic load levels, experimental and numerical results have shown good agreement, resulting in potentially conservative assessments of numerical methods in some cases [37]. Under such low-seismic load conditions, the previously discussed nonlinear anchorage behavior, cabinet rocking, and impact phenomena may not manifest. However, as the seismic load increases, critical responses such as the superposition of global and local modes, yielding of anchor bolts, and deformation of the base frame may go unaccounted for in simplified models, thus requiring careful consideration [25]. Therefore, it is necessary to verify and compare the actual seismic behavior under relatively strong tri-axial seismic loads, including vertical components, which can induce nonlinear anchorage behavior, cabinet rocking, and impact phenomena, with the behavior predicted by numerical models. This study aimed to investigate the seismic behavior of electrical cabinets through a combined experimental and numerical approach. A specimen was designed by fabricating an electrical cabinet model that reflects the dynamic characteristics of electrical equipment installed in Korean-type NPPs and the geometry of a motor control center (MCC), along with a foundation anchorage configured based on field survey. An experimental study was conducted using a simplified model of the newly designed electrical cabinet. Tri-axial shaking table tests were conducted under progressively increasing seismic loads until damage occurred. The anchorage boundary condition was modeled as a fixed support, as is commonly assumed in numerical approaches, to construct the numerical model. The numerical model's validity was verified using the shaking table test results, and a seismic response analysis was conducted with the same input seismic motions. The amplification of the acceleration response was analyzed based on the experimental and numerical results to differentiate seismic behavior characteristics between the two methods.