# Seismic Comparison of Hybrid Steel-Reinforced Concrete and Conventional Frames
## 3 Results and Discussion
### Four-Story Buildings  
The maximum IDR-X value for the r/c four-story buildings is noticed at the first story as 2.5%, which is within the CP level [59] (Figure 18a). The maximum IDR-X occurs at the second story of the steel buildings at 1.8% in the LS level [59] (Figure 18b). The maximum IDR-X value of the hybrid buildings with a fixed interconnection is 3.5% at the first-story level (Figure 18c), which is similar to the r/c buildings.  
The IDR-Y displays maximum values of 2.4% at the r/c buildings, 4.9% at the steel ones, and 2.4% at the hybrid steel-r/c ones, where all presented IDR values are within the CP level [59] (Figure 19). The form of IDR-X and IDR-Y plots is quite similar for the hybrid and r/c four-story buildings, as displayed in Figures 18 and 19.  
The IDR limits [59] are surpassed, showing structural failure, at the r/c four-story model for the excitations of Tabas 90\({}^{\circ}\) and Northridge 90\({}^{\circ}\), at the steel model for Loma Prieta 90\({}^{\circ}\) and Kefalonia 90\({}^{\circ}\), and the hybrid model considering both interconnection types,  
Figure 19: IDR comparison along the \(Y\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed connection) four-story buildings.  
Figure 18: IDR comparison along the \(X\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed connection) four-story buildings.  
for the excitations of Landers 0\({}^{\circ}\), Loma Prieta 90\({}^{\circ}\), and Kefalonia 90\({}^{\circ}\), so these IDR plotlines are omitted.  
The \"PFA/PGA\" varies relative to the rise of the considered four-story buildings in the X and Y directions, as seen in Figures 20 and 21. The \"PFA/PGA-X\" presents the highest value of 3.1 at the top of the r/c and hybrid buildings (Figure 20a,c). The PFA/PGA-X rises to 3.7 at the highest point of the steel frame (Figure 20b), which is a more excellent value by 19.3% than, respectively, for the r/c and hybrid buildings (Figure 20a,c).  
Similarly, the PFA/PGA-Y increases to 3.2 for the r/c and hybrid four-story buildings (Figure 21a,c), which is very close to the top score in the X direction. At the hybrid steel-r/c building, the PFA/PGA-Y increases intensely at the first story, up to 4.1, and has the highest value of 4.8 at the top (Figure 21b), which is bigger by 50% than the respective number for the r/c and hybrid buildings.  
As shown in Figure 22, the base shear ratio \"FX ratio\" has a reduced value of 1.74 for the r/c four-story buildings, a maximum of 3.44 for the steel ones, and 2.16-2.17 for the hybrid ones. In the Y direction, the base shear ratio rises to 1.98 for the steel buildings, shows moderate values close to 1.7 for the hybrid buildings, and a minimum value of 1.33  
Figure 21: “PFA/PGA” comparison on the Y-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed connection) four-story buildings.  
Figure 20: “PFA/PGA” comparison along the X-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed connection) four-story buildings.  
for the r/c buildings (Figure 23). The base shear ratio tends to have more significant values in the X direction than the Y, by 31% for the r/c frames, 70% for the steel ones, and 8.5% for the hybrid frames (Figures 22 and 23).