Investigation of the Effects of CFRP on Load Bearing Capacity of Strengthened Two-Way RC Squared Slabs with Side and Corner Openings

Due to existence of the facility ducts, such as elevators, heating, and cooling systems in buildings, creating of the openings in the reinforced concrete slabs is inevitable. Usually, small openings have negligible effects on the slab performance whereas the large openings can affect significantly on the slab behavior and can cause the stress concentration adjacent to the openings. In some cases, ignoring this issue can cause serious problems in the integrity, stiffness and even stability of structures. One of the rehabilitation and strengthening methods of such slabs is the use of Fiber Reinforce Polymers sheets (FRPs). In this research, the influence of the lateral and corner openings as well as the impact of using a kind of FRPs known as CFRP (Carbon Fiber Reinforce Polymer sheets) for strengthening of two-way slabs were investigated. The obtained results indicate that this method can be successfully employed in remedy operations for mentioned slabs. CFRP sheets can recover the lost flexural rigidity of the slab considerably and even in some cases can improve it in comparison to that of homogeneous slab (slab with no opening). The results also show that by implementing this method the flexural rigidity of the slab can be increased between 12 to 30 percent in the case of slabs with lateral opening and between 1 to 10 percent in the case of slabs with the corner opening relative to the original weakened slab (slab with opening without strengthening).