الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 130 |  |  |
| | | from | 130 | | |
Abstract
Precise prediction of a satisfied punching shear strength is a vital concern and absolutely essential for engineers for making design to a safe structure. So, an important attention has been paid to the different techniques of improving the resistance of flat slab against punching shear failure with the utility of reinforcement systems. In this study a number of vertical prestressed bolts to be located around the column covering the punching zone and fixed at the top and the bottom surface of the slab using a group of nuts and washers, was being presented as punching shear reinforcement. The experimental program comprises the testing of four normal strength concrete specimens of slab- column connections monolithically casted. Considered variable was the number of rows of the used vertical prestressed bolts. Large numerical investigation was carried out using the finite element program ANSYS-V 12.0 so as to widely figure out the role of qualified parameters in enhancing the punching shear capacity. The parameters were the number of rows of the vertical prestressed bolts, prestressing force per bolt, diameter of bolts, thickness of slabs, and the concrete strength. Then, design equations were settled and applied to both the numerical and other’s experimental work and the obtained results were compared to the results of the numerical and experimental programs and the code’s predictions, as well. The obtained results from both experimental and analytical works indicated that the proposed system of prestressed bolts had a constructive effect in enhancing the punching shear resistance and the strain energy of the slab-column connection. Outline Of The Thesis: Chapter (1): contains an introduction for the thesis, the research objectives, and the thesis contents. Chapter (2): presents a literature review of applicable studies on punching shear behavior of slab- column connections and deliberates different methods to enhance punching shear capacity, and finally a discussion of different code’s predictions of punching shear strength is set. Chapter (3): presents the experimental program carried out with the new punching shear system. Besides, it shows the test set-up, material properties, instrumentations, and it ends with a discussion of the test results and a comparison between codes’ predictions and test results. Chapter (4): illustrates a finite element model of the experimental specimens using ANSYS V12.0 and the validity of the numerical model is verified and gives a parametric study using ANSYS V12.0 finite element package with wide variation of the significant parameters such as shear reinforcement ratio, values of prestressing force, thickness of the slabs, and the concrete strength. Chapter (5) presents comparison between the experimental work and the numerical results against various codes predictions. A new design equation is obtained and finally applied on the experimental work and other experimental campaigns and comparison with various codes predictions. Chapter (6): summarizes the work executed in this research and the main conclusions drawn and recommendations for future works.