Connections between new flat slab and existing columns

Abstract

The presented work herein experimentally and numerically investigates the efficiency of four proposed non-monolithic connections between a new concrete flat-slab with an existing concrete column. Furthermore, an analytical study was done by comparing the experimental results to the American (ACI-318, 2019), Euro (EC2, 2014), and Egyptian (ECP 203, 2018) design codes where their subsequent deviations were computed. The experimental study comprised of two sets of full-scale flat-slab specimens tested under monotonic static loading. The first set consisted of five flat-slabs that were connected with interior columns, while the other set included two specimens connected with edge columns. The first set included one flat-slab connected monolithically with an interior column to act as a control specimen denoted to as IN/COL, while the other four specimens were connected non-monolithically. These proposed non-monolithic connections were achieved using dowels, weld, brackets, to key-lock systems and denoted to as IN/DOW, IN/WLD, IN/BRC, and IN/FRC respectively. The second set included one flat-slab connected monolithically with an edge column to act as a control specimen and denoted as EDG/COL, while the other specimen, which was denoted as EDG/BST, was connected non-monolithically using the best chosen non-monolithic connection system from the test results of the first set as the best was bracket connection system. The numerical study was performed by using the ABAQUS program to enrich the test observations and results of the experimental work. The numerical study was done in two stages. The first stage was the validation stage where five models from the total fifty-four performed models were carried out to verify the finite element models against the corresponding experimental specimens. The other forty-nine finite element models were carried out to deeply investigate the influencing parameters of the four proposed non-monolithic connections between flat-slabs and columns in the case of flat slabs with interior columns. The parameters that were studied numerically are: