A sequenced digital twin framework for performance assessment of cracked RC beams with rebar corrosion

Fusion analysis of structural health monitoring and inspection data represents a future trend in comprehensive performance assessment of reinforced concrete (RC) structures. This study proposes a performance assessment method for corroded RC beams based on a sequenced digital twin (S-DT) framework, which integrates monitoring and inspection data across multiple stages of deterioration and mechanical response of the beams. Electrochemically accelerated corrosion and four-point bending tests are conducted on RC beams, which are treated as physical entities, while corresponding three-dimensional (3D) nonlinear finite element models (NFEM) serve as virtual entities. A geometric DT is first established to capture the actual configuration of the test beam. Based on the measured corrosion-induced surface crack widths, a corrosion DT is then developed by coupling the 3D NFEM with a corrosion layer model to estimate the spatial distribution of rebar weight loss, with parameter calibration performed to reduce uncertainty. The error in the estimated average weight loss of the rebar by the corrosion DT is reduced from 30 % to within 5 %. Subsequently, a mechanical DT is constructed by updating the virtual entity through sensitivity analysis and a multi-objective particle swarm optimization (MOPSO) algorithm, integrating measured deflection, strain, and crack width to reflect the mechanical response under loading. The relative errors of the deflection, concrete strain and load-bearing capacity calculated by the mechanical DT, compared with the experimental values, are all within 5 %. Finally, the complete S-DT framework is applied to evaluate and predict the flexural performance of corroded RC beams during service. The results demonstrate that the proposed framework is both feasible and effective, significantly enhancing the accuracy and robustness of structural performance assessment. • A sequenced digital twin framework is proposed for assessment of corroded RC beams. • The geometric digital twin is established based on rebar position data. • The corrosion digital twin is established by considering measured rebar weight loss. • The mechanical digital twin is established by using measured structural responses. • The framework enhances the accuracy and robustness of performance assessment.