الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
One of the major design problems for flat slab structures lies in the shear forces and/or bending moments generated at the connections between the slab and the supporting columns; which leads to punching shear failure. Moment transfer from the slab to the column are always present in flat slabs due to the unsymmetrical nature of the loading, unequal spans. The presence of moment reduces the punching resistance of the flat slab. Furthermore, the presence of openings near the column to accommodate the service utilities may cause further reduction in the punching shear capacity of the slab connection and increase the likelihood of punching failure. There are experimental studies available in the literature that studied the behavior of slabs with opening adjacent to column but not enough to specify the behavior of slab in punching shear under transferred moments from slab to column so more studies are needed to investigate the effect of opening adjacent to column on punching shear strength in the presence of transferred moments from slab to column, also we need to investigate the validity of using different codes equations in case of opening adjacent to column. The main parameters in this study are, the opening size, the location of the opening, additional tensile bars at slab column connection, additional top and bottom bars around the opening that are used to compensate the cutting bars, effect of transferred moments from slab to column and effect of using shear stirrups on punching resistance on RC flat slabs. Forty-two full scale specimens were conducted using the finite element analysis program ABAQUS 16. the slabs were divided into two groups, the first group was for edge column- slab connection and sub-divided into five series with slab dimensions (4000x2000x200) mm for series 1 to series 4 and (4000x2000x250) mm for series 5 and the second group was for corner column- slab connection and sub-divided into five series with slab dimensions (2000x2000x200) mm for series 1 to series 4 and (2000x2000x250) mm for series 5. The flexural reinforcement of the slab was kept constant 1.2%. We concluded from the study of these parameters that the opening size and location have a great effect on punching shear strength. As increasing opening size caused a reduction in punching shear capacity approximately by (32%-44%) and (39%-51%) for edge and corner column- slab connection respectively. On the other hand, when the opening was located in front of column’s face compared to the opening located at column’s corner the punching shear capacity reduced by (32%-22%) and (39%-30%) for edge and corner column- slab connection respectively. As the additional tensile bars percentage at slab column connection increased ranging from 0.3% to 0.98% the punching shear capacity increased by (10%-39%) and (6%-36%) for edge and corner column- slab connection respectively. On the other hand, top and bottom bars around the opening with ratio (AS_conpensated / AS_cut ) ranging from 1.26 to 2.44 caused an increase in punching capacity by (14%-32%) and (4%-16%) for edge and corner column- slab connection respectively. While the transferred moments had a great effect on decreasing the punching capacity, as the transferred moment ratio (M/V) increased from 0.3 to 0.7 the punching shear capacity decreased by (7%-26%) and (15%-37%) for edge and corner column- slab connection respectively. Also, shear stirrups had a significant effect on increasing punching shear capacity as the diameter of shear stirrups increased from 12mm to 18mm the punching capacity increased by (22%-47%) and (10%-41%) for edge and corner column- slab connection respectively. While the number of branches of shear stirrups increased from two to six branches the punching capacity increased by (22%-55%) and (10%-46%) for edge and corner column- slab connection respectively.