The impact of depth on shear behavior of strengthened beams

Abstract

The main aim of this work is to investigate the influence of the beam's depth on the behavior of the externally-strengthened-with-CFRP beams, having shear deficiency. The Nonlinear Finite Element Analysis (NLFEA) has been utilized to construct and validate study models, which had been subjected to load till failure aiming to monitor their performance. Also, the cracking's first appearance, the increase rate of cracking according to loadings, and ductility were all put to observation. The NLFEA results indicated that strengthening the RC beams with externally-bonded CFRP enhanced the beams' shear capacity, in accordance to the study parameters. The strips of CFRP enhanced the beam's ultimate load by 15–19 %. In the NLFEA modelled beams, it had been noticed that the more the beam's depth, the less the shear span-to-depth ratio; as that ratio was 2.7 at a depth of 225 mm, where the ratio became 1.2 at a depth of 450 mm. The depth, of strengthened and control beams, was more influential on the beam's ultimate load than the resultant deflections. Also, the attained findings pointed out that the RC beam's depth had affected the cracking angle; as it was: 33°, 44°, 50°, and 54° at a beam's shear span-to-depth ratio of: 2.7, 1.9, 1.5, and 1.2, respectively. Had a shear crack exceeded the length of a CFRP strip, the stirrup would fail to get to its yield strength. In this case, the influence of the beams' depth is limited. Finally, the obtained NLFEA results were evaluated by comparing them to well-known shear strength models.

Keywords

• reinforced concrete
• beam depth
• shear
• flexural strength
• fiber reinforced polymer
• nonlinear
• finite element analysis