# Seismic Comparison of Hybrid Steel-Reinforced Concrete and Conventional Frames
## 3 Results and Discussion
### Six-Story Buildings  
At the six-story r/c building, the IDR-X value reaches its highest at the first story, measuring 3.1% within the CP level [59], where the IDR-X seems to reduce with the increase in the building height above the first story (Figure 30a). At the steel building in Figure 30b,  
Figure 28: Base shear ratio “FX ratio” comparison for five-story buildings. Figure 27: PFA/PGA comparison along the Y-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) five-story buildings. the maximum IDR-X is displayed at the second story as 2%, within the LS level [59], where the IDR-X tends to decrease along the building height. Similarly, the IDR-Y of the concrete building shows a maximum value of 2% at the first story (Figure 31a) and smaller values above the first story. At the steel building, the IDR-Y has the highest value, 4.2%, inside the CP stage [59]. At the hybrid steel-r/c building with a fixed-pinned connection, the greatest IDR-X is observed at the first story, up to 2.8%, within the CP level [59]. In the hybrid model, the IDR-X, above the first story, decreases with the increase in the building height, close to almost zero, as 0-0.3% values at the fourth story, which is the floor of the steel part linkage with the concrete one. Then, above the fourth floor of the hybrid six-story building, the IDR-X tends to have greater values, up to 1.5%, at the building's top (Figure 30c). Analogously, the IDR-Y shows a maximum value at the first story, close to 3%, a more minor value at the interconnection story, at 0-0.5%, and an intermediate value close to 2.1% at the building's top (Figure 31c). Figure 31: IDR comparison along the \(Y\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) six-story buildings. Figure 30: IDR comparison along the \(X\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) six-story buildings. A surpass of the allowable IDR restrictions [59] is noticed at the r/c six-story building under the earthquake of Superstition Hills 90\({}^{\circ}\); at the steel model under the Landers 0\({}^{\circ}\), San Fernando 90\({}^{\circ}\), Loma Prieta 90\({}^{\circ}\), Chi-Chi 90\({}^{\circ}\), Kefalonia 90\({}^{\circ}\), Tabas 90\({}^{\circ}\), and Northridge 90\({}^{\circ}\) earthquakes; at the hybrid models with a fixed interconnection for the earthquakes of Loma Prieta 90\({}^{\circ}\) and Northridge 90\({}^{\circ}\); and for the hybrid models with a fixed-pinned interconnection for the excitation of Tabas 90\({}^{\circ}\). Consequently, more building failures are found for the steel six-story building, less for the r/c one, and a small number for the hybrid six-story building. At the r/c and steel six-story buildings, the PFA/PGA-X ratio increases variably in building height up to 3 and 4, respectively (Figure 32a,b). At the hybrid steel-r/c building, the PFA/PGA-X ratio tends to increase variably close to 3.9 up to the interconnection story, and then for the upper stories, and it tends to decrease to 0.9-2.9 (Figure 32c) variably. Along the \(Y\)-axis, the PFA/PGA ratio of the r/c building tends to increase variably along the building height up to 3.5-3.7 (Figure 33a). At the six-story steel building, the PFA/PGA-Y ratio varies increasingly up to the range of 4.3-4.5 (Figure 33b). The PFA/PGA-Y ratio of the hybrid building (Figure 33c) presents a similar form to the one for the \(X\)-axis, with greater values up to 3.4 at the fourth story and smaller values at the building's top to 2.4. Figure 33: PFA/PGA comparison along the \(Y\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) six-story buildings. Figure 32: PFA/PGA comparison along the \(X\)-axis for (**a**) r/c, (**b**) steel, and (**c**) hybrid (fixed-pinned connection) six-story buildings. As presented in Figure 34, the base shear ratio, the \"FX ratio\", has values in the range of 2.15-2.17 for the hybrid six-story buildings, slightly smaller than 2.05 for the r/c one, and higher than 2.8 for the steel building.