Experimental study on the effectiveness of strengthening reinforced concrete slab-column connections using CFRP sheets

This paper presents an experimental study on the effect of externally bonded carbon fiber-reinforced polymer (CFRP) sheets on the punching shear behavior of interior slab-column connections. Two square slabs with a concentric column were fabricated, measuring 1200 ´ 1200 ´ 80 mm for the slabs and 200 ´ 200 mm for the column. One specimen served as an unstrengthened control specimen, while the other specimen was strengthened using CFRP sheets. The specimens were simply supported along their edges and subjected to punching tests, with the vertical load applied through the central column. The experimental results revealed that the application of CFRP sheets significantly improved the performance of the slab-column connections. The strengthened slab exhibited a 16.3% increase in punching capacity compared to the control specimen. Additionally, a calculation was conducted to determine the punching shear strength of the test specimens, taking into account the interaction between shear and flexural capacities in a two-way flat slab. This calculation provided a deeper understanding of the impact of CFRP sheet strengthening on the enhancement of the strength of the slab-column connections.