Experimental and numerical investigation into strengthening flat slabs at corner columns with externally bonded CFRP

•1st time corner slab-column connections strengthened via CFRP have been studied.•Slabs with and without near-column openings are included.•An experimental programme on 4 flat slabs is conducted.•FEM used to identify optimal strengthening arrangements.•Optimal strengthening layouts give modest increases in slab ultimate strength. This research investigates the effectiveness of strengthening flat slab to column corner connections by using carbon fibre reinforced polymer (CFRP) sheets. Towards this, four full scale un-strengthened and strengthened flat slab specimens were studied experimentally. Further variation in the test series was introduced via addition of openings near the slab column intersections. The structural performance of the strengthened specimens was compared with that of the un-strengthened specimen in terms of ultimate punching shear resistance, deflection profile and strain profile etc. From the series of slabs tested, it can be concluded that strengthening in the slab without the opening increased the ultimate punching shear capacity by 11%, while in the case of the slab with openings, strengthening increased the punching shear capacity by up to 23%. In parallel with the experimental work, a numerical study was also conducted in order to gain further insight into the structural behaviour of the slabs.