## 4 Conclusions  
A laboratory investigation was conducted on over-reinforced beams with a bolted compression steel plate arrangement using various thickness levels. Based on the results of the investigation, the following conclusions can be drawn.  
1. Bolting the steel plates at the compression zone resulted in a significant increase in the load-bearing capacity of the BCSP beams as the increase in steel plate thickness took place with the control beam. The peak load-capacity of the BCSP beams ranged from 73.7% to 149% of the CB beam. Notably, the BCSP beams sustained higher loads before the appearance of initial cracks. Therefore, the use of steel plates was found to be an effective crack control strategy, which is highly important in ensuring the serviceability of RC structures.
2. It could be concluded that the EA of the BCSP beams increased due to the increase in steel plate thickness compared to the control beam. It was also observed that the increase in EA amounted to by 247.5%, 317.5%, and 462.5% for the beams with 6 mm, 10 mm, and 15 mm steel plate thicknesses respectively.
3. There was also an increase in the beams with the steel plates compared to the CB beam. Meanwhile, the increase in the flexural service stiffness ranged from 73.7% to 122.7%. The steel plates exerted additional resistance against the compressive forces after the concrete cracked.
4. The use of steel plates for the development of over-reinforced beams could contribute to an increase in stiffness of the BCSP beams. This increase was due to the control of the steel plates on the spalling of the concrete cover and the improvement in the failure modes of the BCSP beams.
5. The improvement in the over-RC beams with steel plates led to the transition of the nature of failure from brittle to ductile. The beams sustained higher loads until the ultimate capacities were achieved with the reduction of crushing on the top of the concrete, which was one of CB beam weaknesses due to the sudden brittle failure.
6. Bolting the steel plates to the concrete led to a confining effect on the concrete, leading to less severe horizontal cracks at the compression zone. Notably, due to a more significant confinement effect on the beams, higher steel plate thicknesses were developed, which failed at higher loads.  
Conceptualization, S.A.; methodology, S.A., P.S. and Z.I.; software, S.A.; validation, S.A., P.I. and Z.I.; formal analysis, S.A.; investigation, S.A.; resources, S.A.; data curation, S.A.; writing--original draft preparation, S.A.; writing--review and editing, S.A., P.S. and Z.I.; visualization, S.A., P.S. and Z.I.; supervision, Z.I. and P.S.; project administration, S.A.; funding acquisition, S.A. All authors have read and agreed to the published version of the manuscript.  
This research received the funding no (Project No: GPF015A-2018) by the Faculty Research Grant of the University of Malaya (UM).  
The authors are grateful to the University of Malaya (UM) for the financial support provided by the Faculty Research. The first author appreciates the Department of Civil Engineering, College of Engineering, Al-Mustansiriyah University, and the Ministry of Higher Education of Iraq for providing support for her studies.  
The authors declare no conflict of interest.  
Figure 17: Modes of failure and crack patterns of over-reinforced beams with a side-steel plate (**a**) SBSP and (**b**) SBWP [12].