الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Punching shear is one of the most important criteria that control the design of flat slabs. There are many ways to resist punching shear including increasing of concrete dimensions and using of shear reinforcement. In addition, punching shear reinforcement may be used by setting integrated steel shear head embedded in flat slabs. As the design parameters of shear heads is not well defined in most researches and codes, thus the objective of this research is to investigate the behavior of flat slabs supported by using shear heads to resist punching shear stresses.
Experimental analysis of nine half-scale specimens of flat slabs will be conducted in which several variables including column aspect ratio, length of shear head arm from column face and shear head arrangement will be taken into consideration. All tested flat slabs with overall thickness equal to 150 mm and span equal 2000 mm in both directions with clear spans between supported beams equal to 1800 x 1800 mm.
Experimental program plans were divided in three groups, the first group deals with testing three specimens of flat slabs connected with square columns, one specimen without any shear head as a control specimen and the other two specimens reinforced by steel shear head sections which have lengths equal to 1.75h and 2.25h, respectively from column face. The second group deals with Four specimens of flat slabs connected with rectangular columns. one specimen without any shear head reinforcement as a control specimen with column aspect ratio (2:1) column dimensions (150*300) mm. Two specimens reinforced by steel shear head sections which have a length equal to 1.75h with cut end at angles 90 and 45 degrees. the last one, shear head length equal to 2.25h, to evaluate the effect of increasing shear head length. The third group deals with two specimens of flat slabs connected with rectangular columns having column aspect ratio (4:1) and column dimensions (110*440) mm. One specimen without any shear head reinforcement as a control specimen. The other specimen reinforced by steel shear head sections which have a length equal to (1.75h) with cut end at angle 90 degrees.
This thesis also presents a numerical analysis for punching shear resistance of flat slabs by shear heads. The results of the numerical study demonstrated the efficiency of the proposed nonlinear finite element (NLFE) model by close matching the carrying capacity
of the tested slab specimens their comparative analyzed by the ANSYS program. The comparison revealed the accuracy of the numerical analysis model in the representation of flat slabs whoever with or without steel shear head sections; including predicting the punching shear failure load, the behavior of these slabs, in addition to the crack pattern, strains of the bottom steel reinforcement and strains, shear stresses of shear heads. While the model is slightly satisfactory and reliable in predicting the punching failure load of flat slabs with and without steel shear heads.
Both of ”ANSYS” program and many codes such as (ACI 318-14, EC 2-2004 and ECP 203-2017) were used to investigate the punching shear resistance of flat slabs by shear heads. Based on the results of this numerical analysis study, a proposed equation for calculating the punching shear capacity of flat slabs with shear heads was proposed. This equation can be utilized in the design of such flat slabs that connected with columns having different aspect ratio. Also, general guidelines were suggested for maximum optimum length and arrangement of shear heads.