# Analytical Study of Reinforced Concrete Beams Tested under Quasi-Static and Impact Loadings
## 5 Conclusions  
Based on the results obtained from the experiment and verified by the finite element analyses, the following conclusions can be drawn from this study:  
* Load vs. mid-span displacement curves obtained from finite element models generated by ABAQUS software, for both quasi-static and impact loadings, suggest close correspondence with laboratory results.
* In quasi-static loading on an RC beam (Figure 6) with an adequate number of stirrups, both ABAQUS software and laboratory results verified that the stress in longitudinal tension reinforcements exceeded the yield stress of steel, and the load-carrying capacity of the beam increased subsequent to the yield of tensile steel. This implies that the failure of the RC beam presented in Figure 6 is flexural.
* In all experiments conducted on RC beams under impact loading (Figures 7-11 and Figure 13), the beams failed in shear as opposed to flexure. Thus, there is a correlation between the application of fabric GFRP and the increased shear strength capacity of RC beams. The RC beams strengthened by fabric GFRP depicted a higher load-carrying capacity in both quasi-static and impact loadings compared to that of non-strengthened RC beams (Figure 7, Figure 9, Figure 12, and Figure 13). Fabric GFRP effectively increased the beam's stiffness under both quasi-static and impact loadings (Figure 25).
* The load-carrying capacity of the beam was substantially increased under impact loading, and the impact velocity for the range tested in this study does not affect this increment (Figures 6-13).
* In quasi-static loading on an RC beam (Figure 14 with no stirrups and Figure 18 with an inadequate number of stirrups), both ABAQUS software and laboratory results verified that the RC beam presented in these figures would fail in shear.
* Although the beam's stiffness under impact loading is increased as opposed to that under quasi-static loading, stiffness under impact loading will be reduced by increasing impact velocity (Figure 25).
* Sprayed GFRP (with and without through-bolts) increases the beam's stiffness (Figure 26). The through-bolts are more effective in increasing the beam's stiffness when some steel stirrups are present.
* Using FEM to predict the stiffness of RC beams was more effective for beams tested under quasi-static conditions as compared to those tested under impact loading.  
Considering these results and their implications, this paper has highlighted the possibility of further research with respect to the analytical study of RC beams strengthened by sprayed GFRP under  
Figure 26: Comparison of beam stiffness under quasi-static loading: FEM vs. experimental results.  
impact loading. Research into this field is not as developed as compared to externally bonded fabric FRP, and it is imperative that this gap be narrowed by future works.  
[PERSON] conducted the finite element analysis and prepared the original draft; [PERSON] supervised the project, checked the results, reviewed and edited the paper.  
This research received no external funding.  
The authors declare no conflict of interest.