الفهرس 
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Abstract
One of the most important modes of structural failure, particularly for flat slabs, is the failure of punching shear. That is a brittle, unexpected failure that takes place close to a column or under an area of concentrated load. This type of failure cannot be easily predicted. A significant portion of the concentrated load is applied to a small area of the loaded concrete slab because of the reaction of a column against it, which causes punching shear. An unbalanced moment that is transmitted from the slab to the column may raise the potential for punch shear failure, as well as the interaction between shear and the transferred moment is unavoidable, especially in the corner column.
In this study, a non-linear 3D numerical analysis using ANSYS was performed to investigate the influence of slab and column dimensions on the punching shear capacity of the corner slab-column connection and the shear stress distribution, which was assumed to be linear in different codes.
A detailed three-dimensional model was developed using a nonlinear finite element analysis software. Verification models have been used to simulate existing experimental data. Then, in order to cover more parameter combinations, parametric research was carried out. Two factors were taken into consideration for their influence on the punching shear strength of the concrete: the slab aspect ratio, column aspect ratio, and other factors are constant. Twenty-one models of different slab and column dimensions were investigated, and a relationship between the finite element analysis results for different codes and the numerical results was done, then A comparison between shear stresses computed using two different methods in the Egyptian code, the simplified method, the detailed method, and compare them with the ANSYS models. Also, a comparison between shear stress calculated from Eurocode and ANSYS models was done.
Specimens are divided into three major groups according to slab dimensions and column dimensions, groups A, B, and C are divided according to slab dimensions, and slab thickness, then each group is divided into sub-sets according to column dimensions. The column aspect ratios (1:1, 3:2, 2:3, 2:1, 1:2, 5:2, 2:5). In group A, the specimens are modeled with slab dimensions of (3000x3000x140) mm, while subsets in group B are modeled with slab dimensions of (3000x4000x160) mm, and for group C the slab dimensions of (3000x5000x180) mm. Slabs are reinforced with different flexural reinforcement ratios (1.0%, 1.13%, and 1.15%). The longitudinal compression steel bar mesh is kept constant for all specimens, with a diameter of 12 mm and a spacing of 125 mm in both directions for all specimens. Columns are reinforced with minimum longitudinal steel bars of diameter 22 mm and columns are confined with transverse steel bars with a diameter of 10 mm and spacing 200 mm.
from the study, it was noticed that increasing the column dimension and decreasing the slab dimensions lead to a decrease in the value of shear stress and the β value because the shear stress due to vertical load decreases as the critical section increases and, accordingly, the total shear stress decreases. Increasing the slab dimensions leads to an increase in the transferred moment and the shear stress, which consequently increases the β factor.
from the study results It was observed that the coefficient β for the corner column in ECP 203-2020 is equal to 1.5, which did not agree with the results of ANSYS models.
For obtaining a new value of β, β can be multiplied by a factor that depends on the dimensions of the column and the slab. Otherwise, it is suggested to ignore the simplified method for the angular column and use the exact method.
from ETABS models using the European code, it was found that under the vertical load, the central difference is in the direction of the interior of the slab and that the value of β will be greater than the approximate value in code equal to 1.5, which depends on other factors such as the dimensions of the column and the slab. Therefore, this value can be ignored in the corner column and use the equation for calculated β. Additional further studies are recommended to be investigated to accurately predict the real punching shear stress of the slab-corner column connections with such as a greater number of column aspect ratios, different slab aspect ratios, and different depths.