Analysis of Fiber Reinforced Concrete Deep Beams with Large Opening Strengthened by CFRP Laminates

In this study, the behavior of reinforced concrete deep beams with large opening, used for efficient creation of doors, windows, and passage openings, which were strengthened by carbon fiber-reinforced polymer (CFRP) sheets, is examined. This analysis was carried out using finite element method and ANSYS computer program. The fiber reinforced concrete deep beams were subjected to a point monotonic loading. The results of the suggested analysis procedure were verified with experimentally tested deep beams given in reference [1]. The parametric study examined the CFRP sheets configuration and their thickness used as external reinforcement, and the results of strengthened beams are compared with reference unstrengthen deep beams to insure the effectiveness of external reinforcing method. The strengthened beams indicate an increase in load carrying capacity up to 25, 53 and 59% for vertical orientation CFRP sheets with 0.7, 1.4 and 2.8 mm thickness respectively. On the other hand, horizontal strengthening raises beams strength by 54, 78 and 90% for 0.7, 1.4 and 2.8 mm thickness respectively. Meanwhile deep beams with ring type configuration sheets augmented the strength by 85, 92 and 97% for the three types of the used sheet thicknesses. Load-deflection relationships indicate that the combined reinforced concrete and CFRP laminate system possess some nonlinear deformability. The use of CFRP laminates on the deep beams was found to have an influence on the stress concentration and the mode of failure. Anchoring the CFRP laminates around the opening regions helped in using a larger portion of the strength of the laminates. The deep beams strengthened by CFRP sheets exhibited diagonal shear cracks that were developed at a much slower rate and were ultimately accompanied by the peeling off of the CFRP laminates.