Experimental Comparison of Different Types of FRP Wrapping in Repairing of RC Deep Beams with Circular Openings

Openings of RC deep beams can be used to pass electrical, mechanical, and architectural equipment. These openings can reduce the bearing capacity. Previous studies showed that carbon fiber reinforced polymer (CFRP) sheets could influence RC deep beams' ductility and bearing capacity. In this laboratory reearch, the the impact of aramid and glass fiber reinforced polymer (AFRP and GFRP) sheets on the retrofitting of RC deep beams with the circular opening was investigated. Their response was compared with the performance of CFRP sheets. Depending on the layers (۱, ۲ and, ۳), AFRP, GFRP, and GFRP sheets increased the maximum load of the beams by about ۶۵ to ۹۴%, ۸۷ to ۱۳۰%, and ۱۳۳ to ۱۹۶%, respectively. In RC deep beams retrofitted with GFRP sheets, the sheet separation from the beam surface decreased with expanding the number of layers. The CFRP sheets debonded from the beam surface at the supports along the center of the circular opening. CFRP showed much better performance in energy absorption capacity and load capacity than AFRP and GFRP. The CFRP were debonded from the beam surface at the moment of rupture. However, no significant separation was observed in RC deep beams retrofitted with AFRP and GFRP sheets. SEM images of the cores specimens showed that the fracture surface of the specimens extracted from the beam retrofitted with GFRP and CFRP sheets was much rougher than the control specimen, which indicates a stronger bond between the concrete components.

Keywords:

RC deep beam , retrofitting , opening , Aramid Fiber polymer , Glass Fiber Polymer , Carbon Fiber Polymer