System-Level Deterioration Model for Reinforced Concrete Bridge Decks

Generally, in existing bridge management systems, the deterioration is modeled based on visual inspections where the corresponding condition states are assigned to individual elements. In this case, limited attention is given to the correlation between bridge elements from a structural perspective. In this process, the impact of the history of deterioration on the reliability of a structure is disregarded, as it may lead to inappropriate conclusions. The improved estimate of service life of a bridge deck may help decision makers enhance intervention planning and optimize life-cycle costs. The objective of this research is to evaluate the system reliability of conventional bridges that were designed based on existing codes. According to the methodology developed in this study, the predicted element-level structural conditions for different time intervals are applied in the nonlinear finite-element model of a bridge superstructure, and the system reliability indexes are estimated for different time intervals. This method has been applied in simply supported traditional RC bridge superstructures designed according to Canadian bridge design standards. Based on the reliability estimates, these conventional bridges designed based on the current codes are found to be in good condition during the initial stages of their service life, but their condition degrades faster once corrosion in steel reinforcements is initiated and spalling of concrete becomes evident. The system reliability deterioration model can be integrated into existing bridge management systems by replacing the existing condition index by the reliability index, or by adding it to the assessment process as an additional parameter.