# Seismic Comparison of Hybrid Steel-Reinforced Concrete and Conventional Frames
## 3 Results and Discussion
### Three-Story Buildings  
For the three-story r/c buildings, the IDR-X has a maximum value of 2.9% within the CP level [59] while tending to have greater values on the first floor (Figure 12a). Concerning the steel buildings, the IDR-X scores tend to be higher at the second-story level, with a maximum value of 3.6% within the CP level [59] (Figure 12b). For the hybrid steel-r/c buildings, the IDR-X displays more significant values on the first floor than the second and third ones, with a maximum of 2.2% (Figure 12c), while presenting smaller values than, respectively, for the conventional buildings.  
The plot of the IDR-Y scores for the three-story r/c buildings (Figure 13a) resembles the IDR-X plot's form with the highest value, 2.1%, within the CP level [59]. The IDR-Y plot of the steel buildings presents excellent values at the first-story level, with a maximum of 4.6%, and smaller ones at the second and third stories, even by 4 times (Figure 13b). For the hybrid three-story buildings, the IDR-Y presents more significant values at the first story, up to 2.9%, and is relatively smaller at the second story, up to 2.5%, while at the third story, this is up to 2.3% (Figure 13c).  
Figure 11: Base shear ratio “FY ratio” comparison for two-story buildings.  
Figure 12: IDR comparison along the \(X\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) three-story buildings.  
The IDR in both directions has greater values for the steel three-story buildings than the r/c and hybrid ones (Figures 12 and 13). Exceedance of the permissible IDR limits [59] was noticed at the r/c three-story building for the earthquake of Taba 0\({}^{\circ}\), at the steel building for the earthquake of Kobe 90\({}^{\circ}\), and at the hybrid building with \"fixed\" support for the earthquake of Loma Prieta 0\({}^{\circ}\).  
As displayed in Figures 14 and 15, the PFA/PGA ratio rises with the building elevation for the considered three-story structural cases in the X and Y directions, with greater values at the building's top. The PFA/PGA-X increases up to 2.7 for the r/c building and 3.2 for the steel and the hybrid buildings (Figure 14). As plotted in Figure 15, the PFA/PGA-Y raises to 3.2 for the reinforced concrete building, 4.1 for the steel one, and 3.4 for the hybrid building. Comparing Figures 14 and 15, the PFA/PGA tends to have a slightly greater range of values at the \(Y\)-axis instead of the \(X\)-axis while presenting greater values when considering the steel building, smaller values for the concrete one, and intermediate values regarding the hybrid cases.  
Figure 14: “PFA/PGA” comparison on the “\(X\)-axis” regarding (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) three-story buildings.  
Figure 13: IDR comparison along the \(Y\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) three-story buildings.  
Figure 16 shows that the base shear ratio, the \"FX ratio\", has similar values in the range of 1.76-1.85 for the r/c and hybrid three-story buildings, while a more considerable value of up to 3.75 is seen for the steel buildings, which is almost double the value than the respective one for the other cases. The base shear ratio, the \"FY ratio\", is plotted in Figure 17, showing a reduced value of 1.82 for the r/c building, a greater 2.49 for the steel building, and an intermediate of 2.04-2.05 for the hybrid models with both interconnection types.  
Figure 16: Base shear ratio “FX ratio” comparison for three-story buildings.  
Figure 17: Base shear ratio “FY ratio” comparison for three-story buildings.