# Structural Behaviour of Concrete Deep Beams Reinforced with Aluminium Alloy Bars
## 3 Results and Discussion
### Parametric Study
#### 3.2.5 Transverse Reinforcement Ratio  
The effect of transverse reinforcement ratio, in other words, shear reinforcement ratio (\((100\%\ ^{\star}\ A_{\text{w}})/(b_{\text{w}}\ ^{\star}\ s)\), where A\({}_{\text{w}}\) is the area of AA shear reinforcement and s is the spacing between AA shear links), was investigated by changing the diameter of AA shear links. This effect was examined in two series of beams with different tension reinforcement ratios. As shown in Figure 16, the first and second series of beams had a tension reinforcement ratio of 2.93% and 5.98%, respectively, which were obtained by considering four 14 and 20 mm diameter AA bars as tension reinforcement. The remaining parameters, such as material properties, loading conditions, mesh size, and the a/d ratio in both series, were kept constant, as depicted in Figure 16.  
Figure 16: Examination transverse reinforcement: (**a**) cross-sections; (**b**) elevation.  
Figure 15: Comparison of a/d ratio [46; 53].  
Figure 17 displays the relationship between the transverse reinforcement ratio (%) and the shear force (kN) for two different tension reinforcement ratios, which are 2.93% and 5.98%. This relationship in both series showed a trend that explained that a higher transverse reinforcement ratio contributes to greater shear strength. The enhanced shear strength can be explained by the improved confinement and crack control provided by AA shear links. An increase in transverse reinforcement ratio from 0.12% to 0.84% instigated an enhancement in shear force capacity from 55.6 kN to 76 kN and from 62.2 kN to 83 kN for the beams with a tension reinforcement ratio of 2.93% and 5.98%, respectively.  
It is well known that truss action is less effective in RC deep beams where shear force is transferred by direct compression [32]. As can be seen in Figure 17, shear force capacity slightly increases when the transverse reinforcement ratio is higher than 0.5%. This can be attributable to the fact that the failure is governed by the crushing concrete when the transverse reinforcement ratio reaches certain ratio [53; 54; 55]. Moreover, the results presented in Figure 17 were also compared with the results reported by [PERSON] and [PERSON] [53] and [PERSON] [54; 55] for RC deep beams reinforced with steel bars. According to Figure 18, the behaviour of AA RC deep beams against an increase in transverse reinforcement is identical to RC deep beams reinforced with steel bars. The increase in transverse reinforcement in both AA and steel-RC beams can increase the shear force capacity up to the certain capacity where concrete crushing starts [55]. It should be noted that the tested RC deep beams by [PERSON] and [PERSON] [53] had an a/d ratio of 2, whereas the beams tested by [PERSON] and [PERSON] [54] had an a/d ratio of 0.77. AA bars can be considered as alternatives to steel bars when corrosion is a concern since the behaviour of AA RC beams with increasing transverse reinforcement ratios was similar to that of conventional RC beams, as shown in Figure 18.  
Figure 17: Effect of transverse reinforcement ratio (%).