## 2 The Unreinforced Masonry Infill (UMI)--RC Frame Interaction
Apart from the plastic hinges at the column and beam ends, the damage of specimen \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Concete** \\ **Compressive** \\ **Strength (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Steel** \\ **Reinforcement** \\ **Yield/Ullimum** \\ **Stress (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Clay Brick** \\ **Compressive** \\ **Strength (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Mortar** \\ **Compressive** \\ **Strength (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Masonry** \\ **Diagonal** \\ **Strength (MPa)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Masonry** \\ **Diagonal** \\ **Tension** \\ **Strength (MPa)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Compressive** \\ **Strength (MPa)** \\ \end{tabular} } \\  & & & & & & & **Strength (MPa)** \\ \hline \hline
**(1)** & **(2)** & **(3)** & **(4)** & **(5)** & **(6)** & **(7)** \\ \hline
23.3 & 311/425 & 4.8 & 1.13 / 0.12 & 2.5 & 0.15 & 17.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Basic mechanical properties of all the building materials [23]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Code** \\ **Name** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Initial hor.** \\ **Staffness** \\ **(kN/mm)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **H\({}_{\text{max}}\) Maximum * \\ **Hor. Load (kN)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Normalized ** \\ **Inter-Story** \\ **Drift at H\({}_{\text{max}}\)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Cumulative** \\ **Plastic Energy Till** \\ **H\({}_{\text{max}}\) (kN/mm)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Initial** \\ **Staffness** \\ **Ratio *** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Maximum** \\ **Hor. Load** \\ **Ratio *** \\ \end{tabular} } \\ \hline \hline
**(1)** & **(2)** & **(3)** & **(4)** & **(5)** & **(6)** & **(7)** & **(8)** \\ \hline \multirow{2}{*}{\begin{tabular}{c} Bare F1 BN \\ \end{tabular} } & 8.75 & 15.20 & 1.04\% & 472/10 mm & & & \\ \cline{2-6}  & Decrease Hor. Load 12.50 & 2.65\% & 1927/25 mm & & & \\ \hline \hline \multirow{2}{*}{\
\begin{tabular}{c} F2N \\ infilled \\ \end{tabular} } & 22.12 & 35.30 & 0.80\% & 924/8 mm & & & \\ \cline{2-6}  & & Further testing stopped & & & & 2.53 & 2.32 & 1.96 \\ \hline \hline \multirow{2}{*}{
\begin{tabular}{c} F3 NP \\ infilled \\ \end{tabular} } & 77.84 & 78.10 & 0.80\% & 2743/8 mm & & & & \\ \cline{2-6}  & Decrease Hor. Load 45.00 & 2.55\% & 8076/25 mm & & & & \\ \hline \hline \end{tabular}  
* Average value of measured minimum and maximum load. ** Measured hor. displacement at maximum load normalized by the frame height. *** Ratio of the infilled specimen response by the response of the corresponding bare specimen.  
\end{table} 
Table 2: Summary of the obtained peak response of the bare and the infilled specimens. Figure 7: RC frame + UMI specimen F3 NP [23] (**a**) before applying the mortar facades. (**b**) attaching the wire net. (**c**) applying the cement mortar hosting the wire net to produce (Last row of Table 2). F2N as characterized as widespread diagonal cracking of the masonry infill, whereas for specimen F3 NP, due to the addition of strong reinforced mortar facades together with a stiff peripheral mortar joint, the damage was concentrated at the corners of the masonry infill and the RC column to beam joints. The following summarizes the main observations. 1. The presence of UMI results in a significant increase of the horizontal in-plane stiffness and bearing capacity. The presence of reinforced mortar attached on the facades of the UMI results in a further increase in the horizontal stiffness and load-bearing capacity of the subassembly of a UMI and RC frame (columns 2, 3, 8, and 9 of Table 2). 2.