# Experimental Study of Steel Reinforced Concrete (SRC) Joints
## 4 Experimental Results  
The results that were obtained in the different tested specimens (see Table 3) were compared. The strength and ductility of the P04 and P06 specimens, which respectively used HEB100 and IPN140 as the embedded steel cross-section, were remarkable. As the latter weighed less than the former, the solution with IPN was more economical with proportional mechanical characteristics. It is important to note that for strong deformations, the specimen P07b had considerably less resistance than P04 due to the greater flexural efficiency of the HEB cross-section than the square tube. The thickness of the HEB flanges is 10 mm compared to the 5 mm of the square tube so the HEB section had better resistance against flange buckling. The maximum load that each specimen was able to support was relevant data, but the maximum deflection that it was able to reach and the ultimate load corresponding to that deflection were more relevant. The structural ductility (\(\mu=\Delta\mu/\Delta\text{e}\)) was one of the most important indices for evaluating resistance capacity against earthquakes. At the maximum deflection of specimen P04, the moment at break was 75 kN\(\cdot\)m, which was almost three times the maximum moment that the cross-section resisted in a plastic regime. hat section was able to resist higher deflections than the others tested. In specimen P03, the last break was fast and fragile since the traction bars broke, which ultimately caused the structure to break. Specimen P04 was made as shown in Figure 11A. The reinforcement bars were located around the steel cross-section. Finally, the steel bars and the steel cross-section were placed inside the framework in a T shape. The ultimate breakage of the beam could not be achieved despite the large deformations obtained, since the plastic deformation of the steel section was very large (Figure 11B). The steel cross-section not only provided high ductility to the joints of reinforced concrete but also allowed the structure to have a plastic adaptation capacity. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multirow{2}{*}{ \begin{tabular}{c} **Maxim** \\ **Deflection** \\ \(\Delta\mu\) **(mm)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Moment at** \\ **Break** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Elastic Moment** \\ **Last of the** \\ **Cross-Section** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Plastic Moment** \\ **Last of the** \\ **Cross-Section** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Maximum** \\ **Moment** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Absorbed** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Maximum** \\ **Moment** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{\ \begin{tabular}{c} **Energy** \\ **(kN-m)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Load (kN)** \\ \end{tabular}  } \\ \cline{1-1} \cline{6-10}  & & & & & & & & \\ \hline P03 & 220 & 7.8 & 41.25 & - & - & 55.00 & 14.65 & 73.33 \\ P04 & 330 & 11.7 & 75.00 & 24.75 & 28.65 & 109.50 & 44.88 & 146.55 \\ P05 & 220 & 7.8 & 41.25 & - & - & 108.75 & 23.11 & 145.10 \\ P06 &In the pre-break phase the entire section was plasticized. The concrete lost its tensile and compression resistant capacity, and detached from the section. The reinforcements were plasticized and were sectioned and no longer had resistant capacity. The metal profile continued to maintain a certain strength capacity with large deformations due to its high ductility. The neutral axis continued to rise, especially if the reinforcement was plasticized, since to balance any increase in momentum it is necessary to increase the mechanical arm of the internal forces, because these cannot vary. Figures 12 and 13 show the force-displacement results of the tested specimens. Figure 11: Specimen P04 in its execution phase (**A**) and image of the tested specimen P04 (**B**).