## 7 Conclusions  
In this research study, a series of four-point bending tests were carried on reinforced concrete beams which were strengthened with different amounts and layouts of external CFRP flexural and shear reinforcement ratios. The layout of the CFRP application and the CFRP reinforcement ratio were the main parameters of the research study. Effects of these parameters were studied in terms of moment-curvature values, ultimate load carrying capacities, and failure patterns of the beams. A comparison between experimental and analytical ultimate load carrying capacities of the beams is also presented in this research study. The reinforced concrete beams were divided into two groups. Beams  
Figure 14: Failure pattern of CFRP-B5 at different load levels. Figure 15: Failure pattern of CFRP-B6 at different load levels. in group 1 had a CFRP flexural reinforcement ratio half of that of group 2 beams. However, the CFRP shear reinforcement was gradually increased in the reinforced concrete beams. Based on the results obtained from the experimental study, the following major conclusions are summarized. * The choice of CFRP flexural reinforcement can influence the failure mode and strength gain of the RC beams. The ultimate load carrying capacities and the deformation capacities of the beams can increase to a certain level by increasing flexural or shear CFRP reinforcement. For this reason, a better understanding of beam governing mode of failure is necessary. For instance, a beam which is over-reinforced in flexure may result in the shear failure of the beam. * Increasing the external CFRP shear reinforcement in reinforced concrete beams that have less flexural reinforcement did not result in a significant increase in strength. It was also observed that increasing CFRP flexural reinforcement in absence of external CFRP shear reinforcement did not result in a significant increase in strength. * It was noted that the failure modes of the beams were highly dependent on the CFRP reinforcement layout. For the beams that had higher spacing between CFRP shear strips or no shear reinforcement, the failure occurred near the supports, in terms of diagonal shear cracks having a smaller angle of occurrence. On the other hand, for the beams that had smaller spacing between CFRP shear strips, the cracks that appeared were found to be steep and remained confined within the CFRP shear strips. The presence of CFRP shear strips hindered crack propagation, as well as resisted beam deformations. * The flexural failure of the beams was initiated due to debonding of CFRP strips from the tensile face of the beams. The delamination of CFRP flexural strips started from the mid-span of the beam and moved laterally to the support, proving a bearing failure of the beam. * The analytical procedure proposed by ACI R440.2-08 [33] was used to predict the moment and shear capacities of simply supported CFRP strengthened beams and a good agreement between the experimental and analytical ultimate load carrying capacities of the beam was obtained. Therefore, ACI 440.2R-08 [33] can be effectively used for the design and evaluation purposes of CFRP strengthened reinforced concrete beams. The most significant contributions in this research study were made by M.U.S. and H.J.Q. The experimental scheme of the research study was planned by M.U.S. and H.J.Q., M.N.A., K.K., and H.K. prepared the beam specimens and also cured the beams at later stages. M.U.S., H.J.Q., M.N.A., and K.K. tested the specimens and collected the data. Results were prepared and analyzed by M.U.S., H.J.Q and M.N.A. The original draft was prepared by M.U.S., H.J.Q., and H.K. The review and editing were later carried out by M.U.S. and H.J.Q. This research was supported by the Deanship of Scientific Research (DSR) at King Faisal University (KFU) through its \"Eighteenth annual research project no. 180061\". Authors are thankful to the Deanship of Scientific Research, King Faisal University for supporting this entire research study.