## 3 Results and Discussion  
### Failure Modes and Crack Patterns  
Based on Figures 7a-d and 8, similar crack patterns and failure modes were observed for all the over-reinforced beams. With the increase in the applied load, the flexural cracks were initiated and gradually extended from the mid-span of the beam. Afterward, new vertical cracks started to propagate towards the support regions. The existing flexural cracks at web shear were increased through further load into flexure-shear cracks. It was observed that the cracks widened under the load points after the formation of the flexure-shear cracks. As time passed, the cracks widened more significantly below the loading points. As a result, the maximum spalling of the concrete cover took place in the compression zone at the critical region of the bending moment. The vertical crack was initially formed in the CB beam at a load of 71.5 kN, resulting in the formation of flexure-shear crack at a load of 220 kN. A typical brittle failure was observed in this beam, which could be seen from the crashing of the compressive zone at peak load. At the peak load, there was a remarkable drop in the CB beam's load-bearing capacity, which was defined as peak 1. The load at peak 1 ranged from 356 to 375.5 kN. This peak load was regarded as the failure load of the CB beam due to the spalling and crushing of the concrete cover, as shown in Tables 3 and 4. Moreover, it could be seen in Figures 7a and 8a that the load was considered as the carrying capacity of the CB beam (P\({}_{\text{peak}}\)) from a design point of view, due to the crushing and spalling of the concrete cover. Figure 6: (**a**) Schematic of the test-setup for over-reinforced beam specimens and (**b**) experimental for the BCSP beams test-setup. Figure 7: Modes of failure and crack patterns of all the over-reinforced specimens. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Specimens** & \(\mathbf{P_{\alpha}}\) **(kN)** & \(\boldsymbol{\Delta}\) **(mm)** & \(\mathbf{P_{\alpha}}\) **of Web** & \(\mathbf{P_{Spall}}\) & \(\mathbf{P_{Yield}}\) & \(\boldsymbol{\Delta_{\text{spall}}}\) & \(\boldsymbol{\Delta_{\text{Yield}}}\) & \(\mathbf{P_{Peak}}\) & \(\boldsymbol{\Delta_{\text{peak}}}\) \\
**Designation** & **(kN)** & **Shear (kN)** & **(kN)** & **(kN)** & **(mm)** & **(mm)** & **(km)** & **(km)** \\ \hline CB & 71.5 & 1.87 & 220 & 356 & - & 8.33 & - & 375.5 & 10.8 \\ BCSP-6 & 247 & 3.48 & 322 & 521 & - & 8.2 & - & 652.3 & 11.7 \\ BCSP-10 & 362 & 3.73 & 722 & 635 & - & 6.9 & - & 837.6 & 12.5 \\ BCSP-15 & 460 & 3.99 & 833 & - & 935.3 & - & 10.2 & 935.3 & 15.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Measured values of the type loads of all the over-reinforced specimens. In the case of the specimen, the BCSP-6 beam was developed with the thickness of the steel plate as 6 mm and 24 bolts-compression arrangement. Slow propagation of flexure and flexure-shear cracks was also observed. Additional cracks were found on the concrete cover beyond the peak 1 loading. As for this beam, the observed peak 1 loading amounted to 521 kN. After the crushing of the concrete cover at the peak 1 loading, the beam was able to sustain additional loading, which was identified as the reserve capacity or a pseudo ductility of the beam. Although a slower rate of crack formation was present, higher crushing strength of the concrete cover was observed. The loading was stained by the beam until horizontal cracks were formed in the compression zone at another loading, which was denoted as peak 2. Although the reserve capacity of the beam was retained, a slight decrease in load occurred at this point until total failure occurred at peak 3, as shown in Tables 3 and 4, Figures 7b and 8b. As the peak 2 loading amounted to 560.1 kN, whereas peak 3 loading amounted to 652.3 kN. Meanwhile, the load at peak 2 ranged from 560.1 to 644.2 kN, while the load at peak 3 ranged from 633.14 to 601.3 kN. The BCSP-10 beam was developed with a 10 mm thickness of the steel plate.