New aspects about the effect of critical regions reinforcement on the strength and moment redistribution of RC continuous T-beams (Experimental and numerical study)

Although most of the concrete beams on site are continuous RC girders, there is a lack of interest in the design equations for those concrete elements and the redistribution of moments between critical sections which is a major factor in this design. This paper aims at developing models of 3D nonlinear finite elements (FE) and investigating numerically the influence of the steel reinforcement in the sagging and hogging regions on the performance of the RC continuous T-beams and their effect on the moment redistribution and improvement of the design equations by using the authors' experimental specimens for verification. The two-span RC continuous beams with a loaded central concrete column were manufactured and tested to failure. Forty-one specimens with different lengths were simulated by constructing a FEM, ranging from 2: 10 m for each span, in order to simulate according to reality. The results show that the sagging reinforcement improves the ductility and the serviceability of the continuous beams at the allowable deflection and the permissible crack width. The moment redistribution ratio depends on the ratio between the sagging reinforcement and the hogging reinforcement areas. The described FEM could predict the behaviour of the experimental specimens with acceptable precision.