Time-Dependent Reliability Analysis of Pavement Structures under Fatigue Loading

The premature failure of well-designed structures in the field is a problem commonly observed worldwide. These early failures and the deterioration in structural resistance of pavements can be attributed to the loading and external environmental factors, damage and improper maintenance during the design life among other factors. The time dependence of performance in the formulation of the reliability problem helps to include the effects of degradation of resistance and the variation of loading with time. In this study, the effect of degradation of the surface layer modulus on the fatigue reliability of pavements is analyzed, where the decrease in the modulus with time is considered as a function of the accumulated damage due to repeated loading. The pavement section considered in the study designed for a period of 15 years at a reliability level of 80%, is seen to have a probability of failure of around 50% after 8 years and 75% after 10 years, when strength degradation is considered. This emphasizes the need for capturing the temporal characteristics of the materials and loading in a time-dependent reliability analysis framework