الفهرس 
Punching Shear in Flat SlabsOnly 14 pages are availabe for public view
 |  | from | 277 |  |  |
| | | from | 277 | | |
Abstract
The flat slab system are most commonly used in structures with large spans without beams and garages. However, the main disadvantages of the flat slab system is the punching shear failure especially in cases where openings near columns are required. Thus, the importance of this research is due to the study of the behavior of the flat slabs with openings and the use of various stirrups material as shear reinforcement.
Twenty-six full-scale specimens of flat slabs with openings had various variable parameters; openings’ location, size and shape were firstly tested. Secondly, eight flat slabs specimens with and without openings were tested to investigate the effectiveness of two types of stirrups, steel and Iron-based Shape Memory Alloys. A finite-element analysis was performed to simulate the experimental work, and a comparison of results with various codes provisions was conducted.
Results showed that openings’ shape, size and location from the column’s face and load eccentricity had a noticeable effect on the punching shear strength. Slabs with circular openings achieved higher ultimate and cracking loads with an average increase of 8.25% and 11.83%, respectively than slabs with square, rectangular, and diamond openings at both eccentric and concentric loaded slabs. The diamond shape had a punching strength almost near to a square shape and rectangular opening shape with a 1:3 opening size ratio was better than other opening size ratios.
Also, Iron-based Shape Memory Alloys stirrups are more effective at improving and enhancing the ultimate and cracking loads of flat slabs than mild steel stirrups. Experimental and finite-element results were highly compatible. The American Concrete Institute (ACI 318-19) code showed close prediction for punching shear strength and was being the best, followed by the Euro code 2 and then the Egyptian Building Code (ECP 203, 2018).