The role of shear span to effective depth ratio (a/d) on the deflection in deep and normal reinforced concrete beams when this ratio is (1, 2, 3, and 4)

Abstract

This research presents an experimental study to investigate the role of shear span-to-depth (a/d) ratio for the cross-sectional area of reinforced concrete beam on the deflection in reinforced concrete beams (deep and normal beams), when the value of shear span-to-depth ratio (a/d) equal to (1, 2, 3, and 4) respectively, the behavior of deep beams is significantly different from that of normal beams. Because of their proportions, deep beams are likely to have strength controlled by shear. The a/d ratio is to have a very significant role on the deflection where the values of a/d < 2 (deep beam) and the value of a/d > 2 (normal beam) according to (ACI 318-08) with the constant reinforcement ratio ρ The experimental program included casting and testing four beams with a constant width of cross section (b = 250 mm) and reinforcement ratio ρ. Also, all models of beams tested under two-point loads. The results showed that the percentage of average increasing in value of deflection in normal beam (a/d > 2) 1.68 % from value of deflection in deep beam (a/d < 2). Also, the gained deflection due to load in ranges from (10 to 110 kN) increase by (31.64 %) when a/d > 2 in TB1. moreover, the deflection due to load in ranges from (10 to 190 kN) increase by (21.28 %) when a/d < 2 in TB2. Furthermore, the gained deflection due to load in ranges from (10 to 360 kN) increase by (21.21 %) when a/d < 2 in TB3. as well as, in this research studied the role of shear span-to-effective depth ratio (a/d) on the crack width and the number of cracks.