## 4 Case Study
### Description of the Corner Building  
The frames of the structure are made up of reinforced concrete beams and columns. The slabs are ribbed in two directions with a thickness of 0.20 m and are filled with blocks of clay. The beams have inverted sections with dimensions of 0.50 \(\times\) 0.20 m, and six longitudinal reinforcement bars 10 mm in diameter, and stirrups 6 mm in diameter separated every 0.15 m. According to these dimensions, the beams are embedded within the slabs. The columns have cross-sections with dimensions of 0.35 \(\times\) 0.35 m, with six longitudinal reinforcement bars 16 mm in diameter and stirrups 8 mm in diameter separated every 0.20 m. Both the dimensions of the sections and the reinforcement considered for the elements correspond to conditions similar to those existing in the collapsed buildings in Portoviejo before the earthquake. Figure 4 shows the floor plan of the studied building, with four structural axes in each direction equally spaced every 3.5 m. The masonry infill panels are included toward the north and east ends of the plan. Figure 5 shows elevation views of the building's frames, where the height of the first floor is dedicated to commerce (3.5 m), while the rest of the floors have heights of 2.8 m since they are residences. The resulting model has similar geometric and mechanical characteristics in both the X and Y directions. The characteristics of the materials used in the numerical model are summarized in Table 1. The resistance values of the concrete and steel used in the model are typical of the structures present in Portoviejo when the earthquake occurred. The behavior curve of [PERSON] et al. is used for the model concrete [31], and the Menegotto and Pinto curve is used for the steel [32], which are available in the SeismoStruct program [33]. The resistance of the masonry units is estimated by taking into account that they are of the ceramic type and manufactured with low-quality control [4; 17]. Traditionally, the analysis of this type of building is carried out neglecting the stiffness provided by the masonry, only considering its weight, or its mass in the dynamic analysis. To perform the nonlinear analysis, the characteristics of the macro-model struts are defined, and the compression strut parameters are summarized in Table 2. Of these parameters, the most relevant is the compressive strength, which corresponds to the strength of the masonry infill panel as a whole, not just the masonry units. This parameter shows high variability among the relevant studies consulted [1; 2; 4; 9; 15; 16; 17; 18; 19; 21] and is determined based on the shear strength calculated under diagonal compression. The initial Young's modulus also exhibits high variability and has been determined to be 1000 times the value of the compressive strength, as recommended in previous works [34; 35]. \begin{table}
\begin{tabular}{c c} \hline \hline
**Strength** & **Value** \\ \hline Concrete & 20.6 (MPa) \\ Reinforcement & 412 (MPa) \\ Masonry unit & 14 (MPa) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Strengths of the model materials. Figure 4: Typical plan of the studied building. Figure 5: Elevation views: (**a**) west and (**b**) east. The parameters of the shear strut are summarized in Table 3. The shear bond strength also tends to vary. Among those reported by different authors, a value of 0.3 MPa is selected for this work, which is the minimum reported in [36] and is within the range of values from 0.1 to 1.5 MPa suggested in [37]. The maximum shear strength depends on the masonry shear failure mode (shear friction failure, diagonal tensile failure, and compressive failure). It is estimated by adding an additional resistance to the already defined shear bond strength, reaching a value of 0.5 MPa.