الفهرس 
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Abstract
The main objective of this thesis was to study the punching shear strength and behavior of ultra-High Performance Concrete (UHPC) interior Slab-Column Connections.Thirteen simply supported reinforced concrete slab-column connections were tested in the present study. All slabs had dimensions of 1100× 1100× 100 mm and were simply supported along their four edges (with span= 1000 mm in the two directions). A reinforced concrete stub column, with dimensions 100×100 mm and height of 150 mm, was cast with each slab at its center. The parameters investigated were: concrete strength (56 and 123 N/mm2), fiber volume content Vf% (0, 1, 2, and 3%), fiber shape (end-hooked or corrugated), fiber size with the same aspect ratio, fiber type and material (steel, polypropylene or fiberglass) and punching shear reinforcement (stirrups distributed orthogonal or diagonal and stirrups spacing). Also, nonlinear finite element analysis was carried out for most of the slabs tested in the present study, by using the commercial program ANSYS. The failure load, strains, stresses and deflection results obtained from ANSYS are compared with those obtained experimentally. In addition, thirty-one UHPC slabs were analyzed in the parametric study with dimensions of 1550×1550×150 mm and were simply supported along their four sides to study the effect of steel fiber volume content, the concrete compressive strength and the effect of punching shear reinforcement on the punching load capacity. The effect of the ratio of tension steel reinforcement was studied as an additional factor that may affect the punching strength of UHPC slabs. The results from experimental and numerical study are illustrated and discussed briefly. Some of outcome conclusions from the results illustrate may be summarized as follows for the dimensions and reinforcement used in the present study: 1. The punching shear strength of UHPC slab–column connections can be significantly increased by adding steel fibers. 2. For UHPC slabs, using fibers of different material types (steel, or polypropylene or AR glass), size, or shape (straight, hooked-end or corrugated) had a significant effect on the punching shear strength and ductility of slabs. 3. The surface of the punching shear failure at the bottom side of the UHPC slabs tested extended a distance ranging from 3.0 to 4.0 times the slab thickness measured from the column face, producing a value of 19° to 14° for the failure plane angle. 4. The UHPC slabs with stirrups as punching shear reinforcement distributed in orthogonal directions with spacing d/2 and with spacing d, achieved ultimate load higher than of that of slab without stirrups. 5. The FE analysis predicted well the ultimate loads for both NSC and UHPC slabs.