الفهرس 
Non-Monolithic Connection
Experimental Program And Test ResultsOnly 14 pages are availabe for public view
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Abstract
There is a need to connect new concrete flat-slab with existing concrete column by using the non-monolithic connection systems for the purposes of adding floors to existing buildings. However, there is a lack of design guidelines for such non-monolithic connection. The main purpose of this research is to investigate the efficiency of different non-monolithic connection systems that can be used to connect new flat-slabs to existing columns. Moreover, assessing the available design formulas in different codes (i.e. Euro code 2 (EC2, 2014), American Code (ACI-318, 2019), and Egyptian Code (ECP 203, 2018)) for estimating the punching shear capacity of a flat-slab connected to a column using the proposed non-monolithic systems. In this respect, the previous researchers’ efforts were collected in the field of non-monolithic connections. Experimental and numerical investigations were carried out to create a database that can be used to develop design guidelines of non-monolithic connections.
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 to interior columns, while the other set included two specimens connected to edge columns. The first set included a flat-slab connected monolithically with an interior column, while the other four specimens were connected non-monolithically. These non-monolithic connections were achieved using dowels, weld, brackets, and key-lock systems. The second set included one flat-slab connected monolithically with an edge column to act as a control specimen, while the other specimen was connected non-monolithically using the steel bracket connection system.
The numerical study was performed by using the ABAQUS 6.14 program in two stages. The first stage was the validation stage, where five models simulated the experimental specimens. Forty-nine finite element models were created to investigate the followings:
a- The effect of the dowels embedded length, height difference between X & Y dowels, dowels number, dowels diameter, and slab thickness on the behavior of dowel system.
b- The effect of the weld length and slab thickness on the behavior of weld system.
c- The effect of the brackets’ dimensions, slab thickness, merging the four brackets to behave as uni-column head, and merging shear connectors to the bracket leg on the behavior of bracket system.
d- The effect of the external normal stress, key-lock shapes, and the slab thickness on the behavior of key-lock system
Results of the experimental work show that the four non-monolithic techniques enhance the punching shear capacity of the flat-slab and increase the energy dissipation. However, the non-monolithic techniques increase the slab-column slippage and that’s affect the stiffness degradation.
Results of the parametric study show that increasing dowels embedded length enhances the ultimate capacity of the flat-slab, overlap connection between dowels and flexure steel reinforcement is enough to transfer moment between slab and column, increasing the dimensions of the bracket bearing legs enhances the ultimate capacity of the flat-slab, merging shear connectors to the bracket bearing legs enhances the ultimate capacity of the flat-slab, Eurocode recommendation about the indented surface is valid, and increasing the slab thickness significantly enhances the ultimate capacity of the flat-slab .