Numerical modelling of bond-slip behavior between corroded rebar and concrete using SBFEM

A computational framework based on the scaled boundary finite element method (SBFEM) was established for assessing the mechanical performance of corroded reinforced concrete structures. Nonlinear spring elements were employed to simulate the bond-slip behavior at the steel-concrete interface, while nonlinear truss elements were used to characterize the mechanical properties of corroded steel bars. Quadtree meshing was adopted for efficient discretization of concrete, and a nonlocal macro-micro damage model was introduced to simulate the concrete cracking process. Simulations of pull-out tests demonstrate that the method can accurately capture the bond-slip behavior of corroded interfaces. When the spring spacing is ≤ 1/4 of the bond length, the computational results agree well with experimental data. Simulations of three-point bending tests indicate that post-yield behavior of the steel bar significantly influences the descending branch of the load-displacement curve. After concrete cracking, the mechanical performance of the steel bar dominates the structural response. The proposed SBFEM framework effectively simulates the interfacial behavior between corroded steel and concrete, as well as the overall mechanical degradation process of the structure. This approach provides a reliable analytical tool for evaluating the performance of corroded reinforced concrete structures.