Reliability assessment of reinforced concrete (RC) bridges due to service loading

The performance and reliability of highway bridges deteriorate with respect to time due to aggressive environmental conditions such as corrosion, freeze-thaw, alkali-silica reaction and increasing road freight volumes, resulting in effective influences in service life of the structure as well as potential loss of the economy. Thus, it becomes necessary to consider life-cycle cost with these aggressive environmental conditions during the survival period of degrading highway bridges for better planning and management. In this study, an implementation of time-dependent reliability approaches in the serviceability and safety evaluation of highway girder bridges under aggressive environmental conditions has been investigated for both time-dependent non-stationarities in the loads and strength. The influence of several parameters such as live-load variations, rate of occurrence of live load, degradation of initiation time, strength degradation rate, correlation of strength and number of bridge girders affected on the time-dependent structural reliability of bridges are examined. Parametric analysis is carried out to show the responsiveness of time-dependent structural reliability with the initial strength of component and strength deterioration models. Thus, the analysis of results indicates helpful information that could be employed for superior forecasting of the effective service life of degrading RC bridges as well as in predicting the optimum time for periodic inspection and creating maintenance strategies for continued service life of the bridges.