Full-scale experimental and numerical investigation on the ductility, plastic redistribution, and redundancy of deteriorated concrete bridges

Due to structural degradation, the performance of concrete bridges may degrade with time and result in catastrophic consequences. A novel approach is developed for evaluating the time-variant reliability of multi-girder concrete bridges considering the effects of the load-carrying mechanism and redundancy. By considering three failure modes at both the component and system levels, a new performance indicator is proposed for quantitatively evaluating the load elastic distribution and plastic redistribution among multiple girders. The adverse effects of material deterioration on the structural capacity, ductility, redundancy, load-carrying capacity, and failure mechanism are also investigated and incorporated into the analytical procedure, in which an incremental nonlinear finite element analysis of a 3D fiber beam element is used. Furthermore, the results associated with full-scale destructive tests of two in situ deteriorated bridges, a reinforced concrete (RC) and a prestressed RC (PRC) T-girder bridge, are adopted to evaluate the accuracy of the proposed approach. The feasibility and satisfactory performance of the proposed framework are evaluated using these two real-world bridges. The results demonstrate that the load-carrying mechanism and redundancy significantly affect the structural ultimate load-carrying capacity and time-variant reliability of deteriorating structures.