Experimental study on the determination of reinforced concrete beams flexural capacity for different concrete grades

Reinforced concrete (RC) is composed of two materials such as concrete and steel. Two different materials act together in resisting forces. Concrete is strong in compressive strength and steel is strong in tension strength. The bond between concrete and steel improve the mechanical properties of reinforced concrete. The adherence stress prevents debonding steel from concrete. RC sections design according to various stress states. The one of these states is the effect of bending moments.In design of RC sections, some assumptions are made related to material behavior as well as classical assumptions. As the material such as RC is nonlinear, fragile, stresses on it depend time and load history, it is difficult that the behavior of material takes into consideration. Therefore, the less important variables are neglected and other variables are simplified in the design of RC elements.In this study, the some in the variables effecting on the behavior of RC elements were investigated experimentally. The investigated variables were concrete grades and ratios of reinforcing bars. 15 test beam samples with dimensions of 20x35x300 cm, C20/25, C30/37, C40/50 concrete grade and BÇ IIIa (S 420a) reinforcing bar were produced. The ratios of reinforcing bars placing into beam samples were ? min (=0.8fctd/fyd), ? l (=0.235fcd/fyd) and ? m (= 0.85 ? b) for each concrete grade. The static loading tests were carried out on the beam samples. The theoretical concentrated vertical load (Pu) related to flexural capacities of the beam samples were calculated. Also, the experimental concentrated vertical load (Pexperimental) leading to failure were determined. Then, the ratios of maximum experimental concentrated loads to theoretical ones (Pexperimental/Pu) were obtained.2012, xi + 43 pagesKey Words: Reinforced concrete beam, Flexural capacity, Concrete grade, Ratio of reinforcing bar