الفهرس | Only 14 pages are availabe for public view |
Abstract The shear resistance of concrete structures is a complex phenomenon due to the influence of several mechanisms and the interactions between these mechanisms. Theoretical models for the behaviour of concrete beams subjected to shear were found to considerably differ from one another in their formulation, and it was found that no existing model was able to accurately account for all the factors influencing concrete shear behaviour and the interactions between these factors. The shear design provisions founded in many codes of practice globally used by designers are based on an empirical model of concrete shear behaviour and are augmented using empirical data. Most codes of practice commonly used by designers do not take into consideration the effect of widthto-depth ratio (aspect ratio) as well as the shape effect and also neglect the contribution of dowel action of longitudinal bars. The research program included in thesis, evaluates the effect of cross section shape on shear behaviour of reinforced concrete beams. The main factors studied in this research were: the cross section shape of the beams, the width-to-depth ratio (aspect ratio), shear reinforcement ratio, and the longitudinal tensile reinforcement ratio. Experimental tests was carried out to study the effect of these factors on the behavior of RC beams in shear, besides some analytical studies were done and compared with the experimental results. The experimental program of this research comprised of six medium-scale reinforced concrete beam specimens tested up to failure under static loading conditions. For all beam specimens, the overall length is 2000 mm with a clear span of 1800 mm between the two simple supports, and are loaded at mid-span with a single concentrated load. All of the beam specimens have the same crosssection area which is 126000 mm 2 . The beam specimens B1 through B5 had a rectangular cross section with width-to-depth, b/d, vary from 0.77 to 1.38. Beam specimen B6 is T-shape. The analytical program considered in this study includes performing nonlinear finite element models using ABAQUS v6.10 program. The geometrical nonlinearity, as well as the material nonlinearity for concrete and steel was considered in the models. These models are performed to simulate the beams behaviour and to extend study of the behaviour of such beams. The FE results were compared to those obtained from the experiments and the results agreed in a satisfactory way. Based on the test results, analytical results and review of literature, some conclusion and recommendation were presented |