## 2 Materials and Methods
### \"Unit T-Beams\" with Open Hoop CFRP Strips Employing CFRP Anchor Ropes  
This section presents the measured response obtained from an additional loading sequence investigating a different type of anchoring scheme (Figure 13a) utilizing again the \"unit T-beam\" loading process. This time, before attaching the open hoop CFRP strip at the sides and bottom of the R/C beam, a CFRP anchor rope is inserted from the top through 16 mm diameter holes that are drilled in the R/C slab of the T-beam for this purpose. The effective cross-sectional area of this CFRP rope is equal to 33.1 mm\({}^{2}\) and Young's modulus is equal to 240 GPa. After this CFRP anchor rope has been placed in position through these holes, its fibers are spread at the sides of the beam in a way that this rope becomes flat and obtains a considerable width in order to be attached to the single-layer open hoop CFRP strip, which is put in place from the bottom of the T-beam. This anchoring scheme was studied in two different ways. First, one anchor rope was used with its axis located at the mid-axis of the width of the open hoop CFRP strip. Figure 13: (**a**) R/C T-beam with an attached open hoop FRP strip anchored with an FRP anchor. (**b**) Mode of failure of specimen SW600C/1 No 1. Fracture of the CFRP rope. (**c**) Mode of failure of specimen SW600C/2 No 1. Fracture of the CFRP strip. First, there are the three specimens, using a single anchor rope, with the code name SW600C/1 No1, No2, and No3 (column1, Table 3). In addition, a double anchor rope was placed side-by-side along the width of the open hoop CFRP strip. There are four specimens utilizing this double anchor rope with the code name SW600C/2 No1, No2, No3, and No4 (coulmn1, Table 3). In column 2 of Table 3, the total maximum measured load for each specimen is listed, whereas, column 3 lists the average values of the axial strains measured at both sides of the CFRP strip at the time instant that the specimen was subjected to the maximum load value of column 2. Column 4 of Table 3 lists the axial load valued obtained on the basis of the strain values of column 3 (with the value of Young's Modulus equal to 234 GPa) and the cross-sectional area of the CFRP strip. Because this anchoring scheme used in all these cases is not expected to disturb the distribution of the axial stress field at the location of the four strain gauges, the average value of all four strain gauges during the occurrence of the maximum load is utilized in Table 3. The following are the main observations. (a2) When a single CFRP rope was used in the anchoring scheme of the 1-layer open hoop CFRP strip, the observed failure was mainly at this anchor rope (see Figure 13b). On the contrary, when double CFRP anchor ropes were used to anchor the open hoop CFRP strips the obtained tensile capacity resulted in an effective anchoring scheme leading to the tensile fracture of the single-layer CFRP strip (Figure 13c). (b2) As can be seen from the obtained maximum axial load values listed in Table 3 (column 2), when a single CFRP anchor rope is used the average maximum axial load value is equal to 66.12 kN (SDEV = 4.54 kN, 6.9% of the average maximum value). In comparison, when double CFRP anchor ropes are used then the average maximum axial load value is equal to 86.12 kN (SDEV = 19.58 kN, 22.7% of the average maximum value), representing a substantial increase. The use of double anchor ropes also succeeded in changing the mode of failure from the anchor rope to the CFRP strip in all cases, which should be considered as a preferable performance.