*2.2. Test Beams*

The flexural behaviors of nine BFRP-RC with steel fibers were investigated, together with that of one BFRP-RC beam without steel fibers, which was also investigated as a reference point. All ten beam specimens had the same sizes, i.e., 150 mm wide (b) × 300 mm deep (h) × 2100 mm long (l), and were tested via four-point bending under cyclic loading until failure, as shown in Figure 2. ACI 440 1R-15 [34] stipulates that FRP-RC beams should be designed with concrete crushing failure, and its reinforcement ratio should be greater than 1.4 times of the balanced reinforcement ratio (*ρfb*), which can be obtained via Equation (1).

$$\rho\_{fb} = 0.85 \beta\_1 \frac{f\_c'}{f\_{fu}} \frac{E\_f \varepsilon\_{cu}}{E\_f \varepsilon\_{cu} + f\_{fu}} \tag{1}$$

where *β*<sup>1</sup> is a factor, which can be calculated by Equation (2).

$$\beta\_1 = 0.85 - 0.05 \times (\frac{f\_c' - 28}{\mathcal{T}}) \ge 0.65 \tag{2}$$

The balanced reinforcement ratio of all ten beam specimens was calculated by Equation (1). The design BFRP reinforcement ratios were 0.56% (in the case of 2Φ12 FRP bars), 0.77% (in the case of 2Φ14 FRP bars), and 1.15% (in the case of 3Φ14 FRP bars), respectively. The reinforcement ratios of all beam specimens were higher than 1.4 times the balanced reinforcement ratio. Four levels of steel-fiber volume fractions were investigated, which are 0%, 0.5%, 1.0% and 1.5% respectively. Among them, three types of steel fibers were used as reinforcement when the steel-fiber volume fraction was 1%. Steel stirrups with a diameter of 10 mm and spacing of 75 mm were placed along the whole length of all beam specimens, which ensures that shear failure will not occur. The concrete cover was 25 mm. Figure 2 depicts the details of the beam specimens. Table 6 lists technical details of all beam specimens as well as the actual mechanical properties of concrete making the specimens.

**Figure 2.** Specimen details (all dimensions in millimeters).


**Table 6.** Technical details and actual mechanical properties of concrete for all specimens.
