# Seismic Upgrade of an Existing Reinforced Concrete Building Using Steel Plate Shear Walls (SPSW)
## 5 Seismic Response Results of the Retrofitted r/c Building
### Comparison of EBM and FEM  
From the results presented in the two previous sections, one concludes that the modeling of SPSWs by FEM indicates the ductile behavior of the building and an increase in its lateral load capacity (in terms of base shear). On the contrary, the EBM does not lead to the expected tension-field action, as the equivalent diagonal braces do not yield even though the lateral load capacity of the building increases. Furthermore, the EBM leads to undesirable plastic hinge excursions in 4 out of 6 NLTH analyses. On the other hand, the FEM leads to undesirable plastic hinge excursions only in one NLTH analysis and only for the long configuration of SPSWs. For ease of comparison regarding the number of plastic hinges formed and their performance classification, Tables 9-11 are provided for the worst seismic motion, \"1b.\" In these Tables, the reference (non-retrofitted) and the retrofitted (EBM and FEM) building models are included. In particular, for the FEM building models, i and ii are used to denote the long (Figure 8) and short (Figure 9), respectively, configuration of the SPSWs. It is also noted that the symbol B denotes almost elastic behavior, the symbols C and CP denote the collapse and collapse prevention performance levels, respectively, whereas the dash (-) denotes that no plastic hinge excursion occurs. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**2 nd Storey**} \\ \hline
**Column** & **Position** & **Reference Model** & **EBM** & **FEM i** & **FEM ii** \\ \hline \multirow{2}{*}{C1} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & IO \\ \hline \multirow{2}{*}{C2} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C3} & Base & IO & IO & IO & IO \\  & Top & IO & IO & IO & IO \\ \hline \multirow{2}{*}{C4} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C5} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C6} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C7} & Base & IO & B & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C8} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C9} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C10} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \multirow{2}{*}{C11} & Base & IO & IO & IO & B \\  & Top & IO & IO & IO & B \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Plastic hinges at the columns of the 3 rd storey. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**3 rd Storey**} \\ \hline
**Column** & **Position** & **Reference Model** & **EBM** & **FEM i** & **FEM ii** \\ \hline \multirow{2}{*}{C1} & Base & B & B & - & B \\  & Top & B & IO & B & B \\ \hline \multirow{2}{*}{C2} & Base & B & IO & B & B \\  & Top & B & IO & B & B \\ \hline \multirow{2}{*}{C3} & Base & - & B & - & IO \\  & Top & B & IO & - & B \\ \hline \multirow{2}{*}{C4} & Base & B & B & - & B \\  & Top & B & IO & B & B \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Plastic hinges at the columns of the 2 nd storey.