## 3 Results and Discussion
### Responses of the Beams to Flexural Loads  
Various responses were present in the over-reinforced beams towards the applied loads. To describe the individual responses of the beams, regardless of the presence or absence of steel plates, the characteristics of the beam bending were considered. Furthermore, the loading phases were divided into five phases, as illustrated in Figure 10.  
Figure 10: Location varies of load–displacement curves for all the over-reinforced beam specimens.  
Figure 9: Load–strain relationships for all the over-reinforced beam specimens’ strains up until failure.  
The peak load present in the horizontal cracking in the compression zone was indicated as a spalling load by P\({}_{\text{spall}}\). Meanwhile, the center point deflection of the spalling load was identified as \(\Delta_{\text{spall}}\). The second maximum loading, which was obtained after the spalling load was the peak load, (P\({}_{\text{peak}}\)), with the center point deflection being denoted as \(\Delta_{\text{peak}}\). This peak was identified as a result of the deformation-controlled testing system.  
Five phases of response were identified as the beams were tested, which were represented in the response curve by the areas ranging from 0 to F. The phase 0-A took place before the initial crack was formed on the concrete. As the initial crack was observed, the cracked section responded to the loading in a linear manner, as shown in the second phase A-B. Phase B-C was the non-linear phase before the compressive capacities of the beams was achieved. In this phase, the spalling of the concrete started at point B. Following this phase, the CB beam exhibited highly brittle characteristics, leading to failure of compression shown in phase C-F in the response curve. During the fourth phase, another peak was observed in the beams with the development of steel plates in section C-D due to the redistribution of the internal stresses. Following this peak, the beams with the development of steel plates exhibited a significantly ductile characteristic due to the increased stiffness and strength mobilized by the steel plates. This phase was denoted as D-F.  
Figure 10 presents the load-displacement curves for the center points of the four over-reinforced beams. The maximum capacity of the CB beam was the spalling load. Therefore, the beam in which capacity exceeded this load exhibited highly brittle characteristics. The responses of the beams indicated the influence of the confinement configurations by system development on the behavior of the beams during and after the spalling of the concrete cover. However, the introduction of confinement into the compression zone resulted in an increase in elastic bending stiffness. The BCSP-6 beam experienced a significant capacity increase from P\({}_{\text{spall}}\) to P\({}_{\text{peak}}\), indicating a combination of higher compressive strength and increased ductility. Beyond the peak load, the significantly high load was sustained in the beam. Furthermore, the BCSP-10 and BCSP-15 beams exhibited an increase in section stiffness. A remarkable decrease in load was then observed after the first peak as a result of the spalling o the concrete cover under the two-point loading. However, the only failure in flexure was observed in the BCSP-15 beam, with no horizontal cracks in the compression zone or at the point loads. However, through the increased thickness of the steel plate, it was ensured that the beams' cross-section was maintained with reduced flexural cracks through the redistribution of the internal stresses. Figure 11 illustrates the loads and displacement curves for each over-RC beams with the spalling loads and the obtained displacements. The sections of the curve after the peak load indicated the ductile characteristic of the beams.  
Figure 11: Maximum width of flexural crack for all the over-reinforced beam specimens.