مطالعات آزمایشگاهی اثر ورق های CFRPبر مقاومت برشی تیرهای عمیق دوسر گیردار

Abstract:
Very little researches hasbeen performed about strengthening and repairing of deep beams. In
this paper, shear strength of Reinforced Concrete (RC) deep beams in two cases of repair and
strengthening with Carbon Fiber Reinforced Polymer (CFRP) is evaluated. To achieve the
objective of the research, six deep beams were constructed in three coupling groups with
constant reinforcement arrangement and concrete strength and clear span-to-depth ratio of 2.
In each group, one beam without strengthening was used as reference beam. This beam was
loaded up to failure and then reinforced by CFRP and reloaded again. The other one was
reinforced before loading, similar to the first one. The results indicated that repair and
strengthening the beams would increase the ultimate load. In general, when one directional
CFRP strip is attached to the face of the beams perpendicular to crack with the angle of 45o
(SS45), the ultimate strength is increased by 7 and 61%, respectively. Therefore it can be
conclude that SS45 system because of uniform distribution of CFRP perpendicular to the
direction of shear cracks, could be the best method for repair and strengthening of tested fixed
ended deep beams and in comparison with reference beam, if it used to repair the damaged
beam, the ultimate load would increase up to 7 percent.