Numerical models for composite-jacketed reinforced concrete bridge columns

This paper describes findings from a comprehensive experimental and analytical study on seismic repair and retrofit of model scale bridge columns using advanced composite-material jackets. This study has two phases. In the first phase, fourteen half-scale circular and rectangular reinforced concrete columns were tested for shear and confinement enhancement in a fixed-fixed condition. Three columns were tested in the as-built condition, while ten columns were tested after being retrofitted with different composite-jacket systems. The last column was tested after being repaired with carbon-epoxy composite jacket. In addition to the experimental study, an object-oriented computer program, based on moment-curvature analysis, was written to predict the seismic behavior of all column data. For as-built columns, the program was used to evaluate different shear strength models. However, for repaired and retrofitted column samples, the program was calibrated through a parametric study on two displacement models and six different concrete confinement models. In the second phase of this study, thirteen half-scale circular and square column models with insufficient lap splice length were tested in flexure under lateral cyclic loading. Three column samples were tested in the as-built configuration, whereas ten column samples were tested after being retrofitted with different composite-jacket systems. Another object-oriented computer code was developed for predicting the behavior of the tested columns. The numerical model is based on a moment-curvature analysis of the column section with the inclusion of a bond-slip mechanism. Three different bond-slip models were utilized in the analysis. The developed software was calibrated through a parametric study comparing the experimental and predicted results.