Numerical modeling of repaired reinforced concrete bridge columns

Common repair methods of reinforced concrete (RC) bridge columns involve removal of damaged materials and addition of new materials and components (e.g., jacketing) to replace the removed materials and enhance the damaged region's ductility and/or strength. Ideally, the numerical model of a repaired RC column needs to account for the initial damage of the unremoved materials and provide displacement compatibility with the newly placed material. In order to tackle such challenges, this paper proposes an innovative three-phase fiberbased finite element modeling strategy for the analysis of repaired flexure-dominant RC bridge columns. To this end, four different time-dependent material models are introduced to simulate the changes made to the original column during its repair. These models allow activation, deactivation, replacement, and modification of predefined material models at pre-specified times during an analysis consisting of pre- and post-repair loadings. Additionally, to capture the effects of bar slip (and strain penetration) and bar buckling, a versatile bar-slip model and a novel mechanical bar-buckling model are developed. The developed bar-slip and bar-buckling models are evaluated by comparing their predictions with previous test data. Furthermore, to demonstrate its effectiveness, the proposed modeling strategy is utilized to reproduce the pre- and post-repair responses of four previously-tested RC bridge column specimens with different repair designs.