الفهرس | Only 14 pages are availabe for public view |
Abstract An experimental program was conducted including eight reinforced concrete two-span continuous deep beams. All tested beams were fabricated, instrumented and then tested to failure under the effect of two concentrated loads one being placed at each span. Seven beams were made using high strength concrete whereas one beam was made using normal strength concrete. The main objective of this study was to investigate the behavior of two-span continuous deep beams within the whole range of loading starting from the elastic range up to the failure of each beam. Many significant factors were considered such as: concrete strength, size, shape and location of openings being placed within the interior shear spans. Furthermore, the effect of strengthening of two-span continuous deep beams on its behavior was considered in the case of beams provided with openings within the interior shear spans. The strengthening technique considered was ’bonding exterior carbon fiber reinforced polymers (CFRP). Different strengthening schemes were considered including bonding CFRP strips in the horizontal and vertical directions around the openings. For all tested beams, deflections, strains in the longitudinal flexural reinforcement, and strains in the vertical stirrups were measured and recorded. Also, the initiation and propagation of cracks were recorded. Cracking patterns and failure modes were observed. Cracking loads and failure loads were recorded. Test results revealed the significant effect of the concrete strength and the presence of openings on the shear behavior of tested two-span continuous deep beams. Such behavior was also affected by the shape and size of the openings. Furthermore, it was found that strengthening of those deep beams with openings by bonding CFRP strips resulted in about 20% enhancement in the beam failure load in comparison to non-strengthened beams. However, the failure load of strengthened deep beams is still less than that of solid beams by about 20%. Finally, tested beams were theoretically analyzed using strut-and-tie method. To achieve that, a commercially available program ”CAST” was used. Theoretical results were compared to the experimental ones. |