## 2 Materials and Methods
### Virgin Prototype RC T-Beam without Any External CFRP Strip Shear Reiforcement
Open hoop CFRP strips with mechanical anchors at the West part and closed hoop anchor ropes at the East part (The same as in _Strengthening scheme 2_). The flexural upgrade of the 3 rd strengthening scheme consisted of five (5) CFRP layers (each 0.131 mm thick and 120 mm wide) attached at the bottom side of the T-beam specimen. Figure 20: Comparison of the measured response between the prototype RC Virgin T-beam and this T-beam having been retrofitted with the _1 st and 2 nd strengthening schemes_. (**a**) Shear force versus the deflection at mid-span. (**b**) Bending moment versus the deflection at mid-span. Discussion of the Shear Performance of the Prototype R/C T-Beam without and with Shear Strengthening  
This section summarizes the observed performance of the tested prototype RC T-beam when virgin and compared it with the corresponding performance of the same T-beam being retrofitted with the described in Section 4 strengthening schemes 1 st, 2 nd, and 3 rd. Table 5 lists the measured response in terms of the maximum measured values of shear force (Qm) and bending moment (Mm) for the virgin T-beam, and the corresponding values for the T-beam being retrofitted in three distinct stages as described in Sections 2.2 and 4. The same table also lists predicted maximum shear force and bending moment values, as will be described in what follows. In columns (1) and (2) of this table, the description of this T-beam and the relevant retrofitting scheme is described in brief. Columns (3) and (4) of Table 5 list the measured maximum values of the shear force and the bending moment, respectively. In column (3), the measured increase in the maximum shear force (Qm) that could be resisted during the relevant test, as a result of the applied strengthening scheme, is also listed. These increased values (%) were obtained using as a basis the maximum shear force measured for the virgin T-beam. It must be underlined again here that this specimen was intentionally under-designed in shear. Because of this, the increase in shear capacity that was finally achieved reached 300%. However, in practical cases whereby the structural member will possess a certain level of initial shear capacity from the existing internal shear steel reinforcement, the shear capacity increase by such retrofitting is expected to reach a  
Figure 23: (**a**) The _3 rd strengthening scheme_ (West part). (**b**) The widening of the shear diagonal cracks and the partial crushing of the concrete volume in the anchoring region reduced considerably the effectiveness of this anchoring scheme. Figure 22: Comparison of the measured response between the prototype RC Virgin T-beam, this T-beam having been retrofitted with the _1 st, 2 nd, and 3 rd strengthening schemes_. (**a**) Shear force versus the deflection at mid-span. (**b**) Bending moment versus the deflection at mid-span. rather modest value. The following are the important points that must be considered here from the presented results. * The 1 st Strengthening scheme has the limitation of employing unanchored CFRP strips. This limitation should be considered in design as it means that the full tensile potential of the applied CFRP strip layers is not fully exploited. * This limitation was dealt with by the 2 nd strengthening scheme where all the parts of the external shear CFRP reinforcement were either CFRP strips provided with mechanical anchors (East) or closed hoop CFRP anchor ropes (West). This resulted in such a considerable upgrade of the resulting shear capacity that this prototype RC T-beam could not be forced enough in order to reach its shear capacity at this retrofitting stage. It instead reached its flexural limit state. * Because of this, the 3 rd strengthening scheme was applied in order to upgrade the flexural capacity of the prototype RC T-beam at this stage in order to prohibit the flexural failure and to lead towards reaching again a shear limit state.