# Development of a New Rubber Buckling-Restrained Brace System for Structures
## 9 Results and Performance Evaluation
### Top-Story Displacement  
Seismic damage has a straight relationship to displacement or deformation. The results for top-story displacements were obtained from the maximum values for each corresponding ground motion's time history.  
The results of top-story displacements emphasized the effectiveness of applying the seven selected unique ground motions to obtain an overall representative dynamic structural response. For the RBRBFs models, the average displacement value was 72.46% less than the greatest dynamic value of a bare frame; however, the amplitude cycle of reduction was dramatically changed having RBRBFs, which was doubled. The average reduction of roof displacement for the BRBFs was about 80.6%, which is much lower than the peak response reduction range of bare frames. This shows an improvement of 34.68% in top-story displacement by implementing RBRB instead of BRB.  
The absolute greatest dynamic value of the top-story displacement response was generated by TH Chi-Chi and Cape Mendocino under a MCE seismic level in the X-direction. The displacement was 568.66 mm, which decreased to 139.482 mm and 90.383 mm for BRBFs and RBRBFs, respectively (Figure 55). This variation was due to the decreased building period as a result of the installation of BRB and RBRB devices. Meanwhile, the fundamental period was determined 6.323 s for the existing bare frame, whereas for the BRB and RBRB frames was 2.146 s and 1.07 s. It was presented that RBRBF configuration took the maximum lateral load with less peak displacement and fundamental period among all models.  
Table 18 indicates the comparison of maximum differences through bare frame, BRBF, and RBRBF configurations for TH motions. However, other earthquake records also provided similar trends of percentages to present an overall scenario. Mostly, the results  
\begin{table}
\begin{tabular}{c c c c} \hline  & & **Force (N)** & **Time (s)** \\ \hline \multirow{3}{*}{Cape Mendocino} & **Bare** & 1,635,466 & 7.92 \\ \cline{2-4}  & BRB & 1,615,129 & 6.78 \\ \cline{2-4}  & RBRB & 2,485,108 & 9.92 \\ \hline \multirow{3}{*}{Chi-Chi} & **Bare** & 1,490,206 & 30.43 \\ \cline{2-4}  & BRB & 1,809,701 & 41.385 \\ \cline{2-4}  & RBRB & 2,116,665 & 30.57 \\ \hline \multirow{3}{*}{Darfield} & **Bare** & 1,722,826 & 26.9 \\ \cline{2-4}  & BRB & 2,459,918 & 24.845 \\ \cline{2-4}  & RBRB & 3,337,210 & 29.92 \\ \hline \multirow{3}{*}{Imperial Valley -6-1} & **Bare** & 1,460,406 & 7.07 \\ \cline{2-4}  & BRB & 2,335,609 & 7.405 \\ \cline{2-4}  & RBRB & 3,046,340 & 7.265 \\ \hline \multirow{3}{*}{Imperial Valley -6-2} & **Bare** & 903,053 & 9.475 \\ \cline{2-4}  & BRB & 1,566,998 & 11.76 \\ \cline{2-4}  & RBRB & 2,469,554 & 6.56 \\ \hline \multirow{3}{*}{Landers} & **Bare** & 1,679,185 & 25.22 \\ \cline{2-4}  & BRB & 1,932,930 & 27.9 \\ \cline{2-4}  & RBRB & 2,979,704 & 17.84 \\ \hline \multirow{3}{*}{Loma Prieta} & **Bare** & 1,736,497 & 5.84 \\ \cline{2-4}  & BRB & 1,815,410 & 10.815 \\ \cline{1-1} \cline{2-4}  & RBRB & 2,222,518 & 4.765 \\ \hline \end{tabular}
\end{table}
Table 17: Maximum base shear force in MCE level in Y-direction.  
indicate that RBRBFs provide better safety for the structure in comparison to BRBFs due to the added resistance to the system by its rubber components.