## 4 Experimental Results
### Specim Failure  
The total vertical load-midspan deflection relationship for selected specimens is presented in Figure 5. Figure 6 shows the final appearance of all specimens. Almost all beams in series B1 failed in flexural followed by shear (flexural-shear failure), except B1-2-1.5. The specimen B1-2-1.5 showed arch action instead of beam action. The inclined cracking in specimen B1-2-1.5 claimed that the load was transferred directly to the support through compression strut. Therefore, the failure mode of specimen B1-2-1.5 was compression strut failure. For the beam failing in flexural or flexural-shear, the strain gauge attached on a longitudinal reinforcing bar proved that the yield strain occurred when the peak strength of a specimen was reached. In general, flexural and shear cracks appeared and the crack opening at the middle of beam gradually increased as the vertical load increased. It can be seen in Figure 6, that the beams of series B1 (except B1-4-1.5) showed cracks around the concentrated load. Specimen B1-4-1.5 showed a horizontal crack and a vertical crack that opened gradually at the middle of the specimen. The failure mode of specimen B1-4-1.5-1 consisted of flexural-shear and bond splitting failures. \begin{table}
\begin{tabular}{c c} \hline
**Specimen ID** & **Concrete Compressive Stress (MPa)** \\ \hline B1-2-0.75, B1-2-1.50 & 82.4 \\ B1-3-0.75, B1-3-1.5 & 78.2 \\ \hline B1-4-0.75, B1-4-1.5 & 78.2 \\ \hline B2-2-5-2-5-1, B2-2-5-2.5-2 & 61.5 \\ \hline B2-3-2-5-1, B2-3-2-5-2 & 62.4 \\ \hline \end{tabular}
\end{table} 
Table 4: Compression test results for concrete cylinders. Figure 5: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Reinforcing Bar Size** & **Specified Yield Stress** & \multicolumn{2}{c}{**Test Results (MPa)**} \\ \cline{2-4} **(Diameter [mm])** & **(MPa)** & **Yield Stress** & **Ultimate Stress** \\ \hline \#4 (12.7 mm) & 785 & 785 & 978 \\ \#8 (25.4 mm) & 685 & 703 & 907 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Tensile test results for reinforcing bars. Figure 5: The force-middle span deflection curves for selected specimens. Figure 6: The final appearance of beam specimens at the end of tests. Specimens series B2 consisted of 4 SFRC beams. Three of four specimens failed in shear. The failure mode of B2-3-2.5-1 was a combination of compression failure due to flexural and web crushing, where yielding of the longitudinal reinforcing bars occurred. For beam B2-2.5-2.5-1, the diagonal cracks appeared as the load gradually increased. Small flexural cracks also appeared. A large diagonal crack and horizontal crack appeared on one of the shear spans, followed by the crushing of concrete directly at the top of the beam (around the concentrated load). These failure modes show that beam B2-2.5-2.5-1 had a combination of diagonal tension and shear compression failures. For beam B2-2.5-2.5-2, the diagonal cracks appeared as the load gradually increased. The crushing of concrete occurring around the concentrated load and large diagonal crack in one of shear spans occurred simultaneously. The final appearance of beam B2-2.5-2.5-2 shows that the beam failed due to a combination of diagonal tension and shear compression failures. For beam B2-3-2.5-1, cracks started appearing from the middle of both shear spans (left and right shear spans); it then propagated to the middle span around the concentrated loads. Cracks on the middle span became larger, and crushing of concrete at the top of beam occurred. In addition, it was found that yielding of the longitudinal reinforcement occurred in specimen B2-3-2.5-1. Therefore, beam B2-3-2.5-1 failed due to web shear crushing and flexural failure. Beam B2-3-2.5-2 failed due to diagonal tension and shear compression failures. As the vertical load gradually increased, cracks appeared on both shear spans. Cracks tended to propagate to the middle span around concentrated loads. The crushing of concrete at the top of the beam occurred first, and width of diagonal crack became larger accordingly.