Reliability-based condition assessment of an externally restrained bridge deck system considering uncertainties in key design parameters

The objective of this research is to evaluate the reliability of bridge decks that use nonconventional materials or structural forms such as externally restrained deck systems where the available deterioration models developed for conventional systems are not applicable. The method developed here adopts the reliability theory and establishes a deterioration model for such bridge decks based on their failure mechanisms. The externally restrained deck is an innovative structural system introduced about a decade ago to the construction industry and provides corrosion-free replacement for conventional reinforced concrete decks. Because there is no established deterioration model available for these innovative systems, it is difficult to predict the reliability of such bridge decks at different instances of time. The developed method has been applied to an innovative structure with an externally restrained deck system, namely the Crowchild Trail Bridge, in Calgary, Canada, as a case study. A finite-element model of the bridge has been developed and calibrated with experimental results giving static deflection, vibration characteristics, load distribution, and crack patterns. The system reliability has been determined at different times using the proposed method. The results show that the design is quite conservative and there is a very low probability of failure for such a system during its design life.