## 4 Overview of Pseudo-Dynamic Testing and Result Analysis
### Overview of Existing Seismic Test Methods  
The impact of an earthquake on a structure depends on the ground acceleration and the type, weight, and stiffness of the structure. The horizontal earthquake acceleration induces shear stress on the vertical members of the structure, which support the structure. This then subjects the structure to relative lateral motion. In general, when an earthquake occurs, many structures, even after large deformation, support themselves without structural collapse. In the process, however, they are likely to absorb some energy through nonelastic behavior. More specifically, while the seismic load is being transmitted to a structure, some materials in the structural system reach their yield points, thereby causing localized plastic deformation to occur. The resultant large amount of earthquake input energy then starts to be absorbed by the structure through nonelastic behavior. It is, however, still very difficult or impossible to theoretically assess such nonelastic behavioral characteristics even though a wide range of relevant computing programs have been developed. For that reason, the nonelastic seismic response of a structure has been mostly experimentally studied with various test methods, including shaking table tests, quasi-static tests, and pseudo-dynamic tests. The shaking table test method is considered to be the most effective way to assess the seismic behavior of structures, but the maximum weight and size of specimens are limited by the size and capacity of the applied shaking table. Thus, in most cases, reduced-size models are used, and this may lead to issues arising from the discrepancy between the model and the actual structure. In an attempt to overcome this limitation, quasi-static tests have been widely used to assess the nonelastic behavior of full-size structures, in which the test conditions are controlled by the displacement or load. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Division** & \multicolumn{5}{c}{**Performance Requirements**} \\ \hline \multirow{5}{*}{Criterion 1} & Cycle & \(1\) & \(2\) & \(3\) & Average \\ \cline{2-6}  & Q\({}_{max}\) (kN) & \(139.7\) & \(141.6\) & \(144.5\) & \(141.9\) \\ \cline{2-6}  & Q\({}_{min}\) (kN) & \(-160.7\) & \(-162.6\) & \(-165.9\) & \(-163.0\) \\ \cline{2-6}  & (Q\({}_{max}-Q_{ave}\)) \(Q_{ave}\) & \(-0.01\) & \(-0.002\) & \(0.01\) & \\ \cline{2-6}  & (Q\({}_{min}-Q_{ave}\))/\(Q_{ave}\) & \(-0.01\) & \(-0.002\) & \(0.01\) & \\ \cline{2-6}  & Results & Conforming & Conforming & Conforming & - \\ \hline \multirow{5}{*}{Criterion 2} & Cycle & \(1\) & \(2\) & \(3\) & Average \\ \cline{2-6}  & Q\({}_{max}\) (kN) & \(192.5\) & \(196.3\) & \(202.0\) & \(196.9\) \\ \cline{2-6}  & Q\({}_{min}\) (kN) & \(-208.7\) & \(-212.5\) & \(-214.4\) & \(-211.8\) \\ \cline{2-6}  & (Q\({}_{max}-Q_{ave}\))/\(Q_{ave}\) & \(-0.02\) & \(-0.003\) & \(0.02\) & \\ \cline{2-6}  & (Q\({}_{min}-Q_{ave}\))/\(Q_{ave}\) & \(-0.01\) & \(0.002\) & \(0.01\) & \\ \cline{2-6}  & Results & Conforming & Conforming & Conforming & - \\ \hline \multirow{5}{*}{Criterion 3} & Cycle & \(1\) & \(2\) & \(3\) & Average \\ \cline{2-6}  & \(E_{D}\) (kN-m) & \(16.4\) & \(16.1\) & \(17.1\) & \(16.5\) \\ \cline{1-1} \cline{2-6}  & (\(E_{D}-E_{D,ave}\))/\(E_{D,ave}\) & \(-0.008\) & \(-0.02\) & \(0.03\) & \\ \cline{1-1} \cline{2-6}  & Results & Conforming & Conforming & Conforming & - \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Conformance evaluation of NBSD\(-2\) as a seismic control system. Meanwhile, pseudo-dynamic testing was designed and developed to have only the advantages of both the shaking table test and the quasi-static test methods [41]. It is a hybrid experimental and numerical approach that combines experimental techniques with numerical analysis. Pseudo-dynamic testing is composed of two parts: numerical analysis and loading tests on specimens.