A numerical model for predicting the behavior of rehabilitated and/or strengthened RC beams

Department of Civil Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi ArabiaThe work presented herein uses the compatibility of deformations, equilibrium offorces, and a more rational stress-strain relationship for concrete in compression to suggest a numerical model that is capable of estimating, for any load level, the forces, moments, stresses, strains, and curvatures of the rein-forced concrete beams before and after repairing, upgrading and/or strengthening. The model considers the variation of stresses, strains, and curvatures along the length of the beam. It also accepts different material properties, cross sectioal shapes, and loading and reinforcement configurations. Further, it takes into account effects of shrinkage and creep on the deflection and the strain of concrete and internal and external reinforcement. Thus, it can be used with different techniques that are available for rehabilitation and/or strengthening of reinforced concrete beams. The analytical prediction using the proposed model was checked against the published experimental data and found in good correlation with the corresponding measured results. It also accorded better prediction than other models available in the literature. It is believed that availability of such a model is of great value to the structural engineer especially through the design and decision process. It can be used to evaluate the strength and serviceability criteria of the existing damaged or undamaged structure. Then, if needed, the model can be utilized to help in selecting the type and size of the material that best fulfills the conditions to rehabilitate and/or strengthen the structure. This will, of course, influence the work strategy and may lead to appreciable saving in both time and cost