## 7 Conclusions and Discussion
Finally, the experimental shear strength of these beams, together with the ones provided by many authors in the literature, were compared to the predicted values calculated by the code equations in Eurocode 2 [70], CNR-DT 200/2013 [66] and fib bulletn 14 [67] that provide two different design approaches. The results of these comparisons have showed that:  
1. Before retrofitting, the Variable Angle Method [70] gives values of the shear strength that result in good agreement with the experimental results. The shear carried by the stirrups, considering the real shear crack angle, may be 2.12 times greater than the one estimated considering an inclination angle of 45\({}^{\circ}\). 2. After CFRP retrofitting, the experimental beam shear strength is, on average, 1.21 times greater than the predicted one assuming a crack inclination angle of 45\({}^{\circ}\) without considering the concrete contribution (CNR-DT 200/2013 [66]). The predictive model capacity should be improved considering the uncertainties about each shear strength contribution. 3. The concrete contribution predicted by code equation [70] is similar to the experimental one for the tested beam DB1-R and DB2-R. Further research efforts should be undertaken because the steel and CFRP reinforcement contributions are uncertain. 4. The CFRP reinforcement contribution to the shear resistance could be overestimated by the design model [66]. This resisting model seems improper for evaluating the FRP contribution because: i. The brittle failure of the CFRP shear reinforcement does not permit plastic force redistribution; ii. The number of CFRP strips that contribute efficiently to the shear resistance is uncertain; iii. The maximum FRP fabric deformation is still uncertain. 5. The experimental CFRP strain can be modest and comparable to the yield strain of the steel reinforcement. In this case, the transverse steel contribution to the shear resistance can be smaller than the one predicted by code equation [70]. Further research efforts are needed in order to understand better:  
1. The effect of the material property variability on the capacity of \"real\" beams
2. The strength of the \"real\" beam retrofitted with proper new rebar anchorages
3. The resisting mechanism of the retrofitted beams based on physical assumptions. [PERSON] makes substantial contributions to conception and design, acquisition of data, analysis and interpretation of data, analytical elaborations, writing the article and revising it critically for each content. He gives final approval of the version to be submitted and any revised version. [PERSON] makes substantial contributions to conception and design, analysis and interpretation of data, revising the paper critically for important intellectual content. He gives final approval of the version to be submitted and any revised version. [PERSON] makes substantial contributions to conception and design, acquisition of data, analysis and interpretation of data, analytical elaborations, writing the article and revising it critically for each content. She gives final approval of the version to be submitted and any revised version. The authors gratefully acknowledge the funding by \"The Laboratories University Network of seismic engineering\" (ReLUIS) thanks to the research project ReLUIS/DPC 2015-2018. The authors wish to express their gratitude to Interbau s.r.l. for providing CFRP sheet and adhesive for the specimens. They also thank the Italian Ministry of Public Works and The Italian State Property Office. The writers would also like to express their appreciation for the technical support given by the staff at the Proof testing and Research in Structures and Materials Laboratory (PRiSMa) of the Roma Tre University (Rome, Italy). The authors declare no conflict of interest.