FE modeling of inelastic behavior of reinforced high-strength concrete continuous beams

A finite element model for predicting the entire nonlinear behavior of reinforced high-strength concrete continuous beams is described. The model is based on the moment-curvature relations pre-generated through section analysis, and is formulated utilizing the Timoshenko beam theory. The validity of the model is verified with experimental results of a series of continuous high-strength concrete beam specimens. Some important aspects of behavior of the beams having different tensile reinforcement ratios are evaluated. In addition, a parametric study is carried out on continuous high-strength concrete beams with practical dimensions to examine the effect of tensile reinforcement on the degree of moment redistribution. The analysis shows that the tensile reinforcement in continuous high-strength concrete beams affects significantly the member behavior, namely, the flexural cracking stiffness, flexural ductility, neutral axis depth and redistribution of moments. It is also found that the relation between the tensile reinforcement ratios at critical negative and positive moment regions has great influence on the moment redistribution, while the importance of this factor is neglected in various codes.