## 4 Seismic Fragility Assessment Results
It is observed that the collapse performance criteria of FEMA P695 were satisfied when the amplification factors 1.2 and 1.5 were used. However, the collapse performance criteria was not satisfied when the amplification factor 1.0 was used. In addition, amplification factor 1.5 improved the collapse probability at MCE and ACMR only minorly compared to amplification factor 1.2. Therefore, 1.2 can be a marginal value for the amplification factor of shear force. Figure 16 shows relationship between the axial force ratio and the collapse probability of individual component walls shown in Table 10. Component walls having an axial force ratio of 10% have collapse probabilities from 2.4 to 5.3% while component walls having an axial force ratio of 30% have a collapse probability from 4.4 to 9.9%. Therefore, the collapse probability of shear walls tend to increase as the axial force ratio of those walls increases. This result is consistent with the fact that the deformation capacity of shear walls usually decreases with higher axial force ratio. In Figure 17, collapse fragility curves for individual walls comprising Model A are shown as an example. Those fragility curves were calculated for each EDP, respectively. Table 13 presents failure probabilities at the MCE for each EDP obtained from the collapse fragility curve plotted in Figure 17. The failure probability for each EDP was calculated for individual walls to determine which EDP is dominant. The EDP with the highest collapse probability among the five individual walls comprising a wall group model was chosen as the primary failure mode of the wall group model and is shown in Table 13. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Evaluation Category**} & \multicolumn{3}{c}{**Performance Evaluation of MCE Collapse Probability**} \\ \cline{2-4}  & **Design to \(1.0V_{u}\)** & **Design to \(1.2V_{u}\)** & **Design to \(1.5V_{u}\)** \\ \hline MCE collapse probability (\%) & 10.6 & 8.1 & 7.9 \\ \hline Performance evaluation of MCE collapse probability (Less than 10\%) & Fail & Pass & Pass \\ \hline ACMR/ACMR10\% & 0.97 & 1.05 & 1.06 \\ \hline Performance evaluation of ACMR (ACMR ratio is 1 or higher) & Fail & Pass & Pass \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Evaluation results for each design shear. Figure 16: MCE collapse probability by axial force ratio. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Analytical Model**} & \multirow{3}{*}{**Component**} & \multicolumn{6}{c}{**Collapse Probability by MCE (\%)**} & \multicolumn{6}{c}{**Primary Failure Mode**} \\ \cline{3-11}  & & \multirow{2}{*}{**Drift**} & \multicolumn{2}{c}{**Rotation**} & \multicolumn{2}{c}{**Compressive**} & \multicolumn{2}{c}{**Shear**} & \multicolumn{2}{c}{**} \\ \cline{3-11}  & & & & **Angle** & **Strain** & **Design to 1.0\(V_{\mathbf{s}}\)** & **Design to 1.2\(V_{\mathbf{s}  
For individual component walls of Model A, the plastic hinge rotation angle has the highest collapse probability in most walls, but the highest collapse probability (11.2%) observed in the longest wall (R3) corresponds to the shear failure for amplification factor 1.0. As a result, the primary EDP changes from shear failure to plastic hinge rotation angle failure as the amplification factor to shear increases from 1.0 to 1.2 and 1.5, which reduces the potential of shear failure in the walls. Model B has a tendency similar to Model A, but shear failure is the primary failure mode of T1 and T2 as well as R3, and the transition from shear failure to plastic hinge rotation angle failure occurs at the amplification factor 1.2. In the case of the Model C, unlike the other two models, the wall with the highest collapse probability was R1, of which the failure mode is the compressive axial strain failure without change, in spite of the increasing amplification factor to shear force. This is due to the high axial force ratio of R1 caused by the small cross-section area and the characteristics of high-rise buildings.