## 2 Formulation of Analytical Model
### Modelling Strategy of Traditional Masorry Panel  
In this study, the equivalent compressive strut model was employed to evaluate the impact of a traditional infill masonry panel in comparison with the SIM panel. The initial development of the strut model can be attributed to [PERSON] (1960), who formulated the concept based on elastic theory (19). [PERSON] proposed that the response of traditional infill masonry panels under lateral loads could be effectively analyzed by representing their impact through an equivalent diagonal compressive strut. Various types of strut models are available in the literature, with the most commonly used ones being the single, double, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Load case** & **Location** & **Importance Level** & **Site Class** \\ \hline  
\({}_{\text{e}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Case details for each structure. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Criteria 1** & \multicolumn{2}{c}{**Criteria 2**} & \multicolumn{2}{c}{**Criteria 3**} \\ \hline
**Location** & **Hazard Design** & **Importance** & **Probability** & **Site** & **Spectral Shape** \\  & **Factor, Z** & **Level** & **Factor, k\({}_{\text{p}}\)** & **Class** & **Factor, C\({}_{\text{h}}\)(T\({}_{\text{1}}\))** \\ \hline Newcastle & 0.11 (Low risk) & 2 & 1 & C\({}_{\text{e}}\) & 2.34 \\ Dowerin & 0.2 (Medium risk) & 3 & 1.3 & D\({}_{\text{e}}\) & 3.68 \\ Macquarie Island & 0.6 (High risk) & 4 & 1.8 & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Criterion employed for determination of equivalent static force. and triple strut models. [PERSON] (1997) conducted a comprehensive study comparing the impact of the three different types of strut models on the structural response of an infilled frame, utilizing finite element analysis, and contrasting the findings with experimental results (20). The conclusions of the study indicated that while the single-strut model is the simplest rational representation for analyzing infilled frames, it falls short in describing the local effects of interaction between the frame and the infill panel. [PERSON] suggested that using multi-strut models (double and triple strut) can address this limitation without significantly increasing the complexity of the analysis. It was also reported that the single-strut model is the most widely used and suitable for large structures. The single-strut model was chosen in this study, as the local effects of panel and frame interaction are not the primary focus. Furthermore, within the context of this investigation, a three-bay, three-story structure qualifies as a large structure for an equivalent compressive strut model. As previously mentioned, the reinforced concrete frame with a traditional masonry panel can be effectively modeled as an equivalent braced frame featuring an equivalent diagonal compressive strut, as illustrated in Figure 6.  
Various studies in the literature offer methodologies for determining the width of the equivalent diagonal strut. To model SIM panels, trial and error analysis was used, as the in-panel capacity of the SIM panels also depends on the displacement. In this study, the selection of an empirical equation to represent the equivalent width of the diagonal compressive strut for the traditional masonry panel is crucial. FEMA273 (21) recommends the use of the empirical equation proposed by [PERSON] and [PERSON] (22) for quantifying the strength, stiffness, and deformation capacity of the traditional masonry panel (Equation (4)). Figure 5: Modeling of bare frame: (**a**) Geometry of bare frame; (**b**) Model of bare frame in Strand7. Figure 6: Representation of diagonal compressive strut for traditional masonry: (**a**) Traditional masonry panel; (**b**) Replacement of traditional panel by equivalent diagonal compressive strut. For static analysis in Strand7, the equivalent width of the compressive strut was set at 0.434 m for this study.