Assessment of time-dependent structural resistance of RC bridges in Barak Valley, Assam, India

Reinforced concrete (RC) bridges deteriorate due to strength loss induced by aging of the structure, extreme weathering conditions and unplanned increased service loads. These load variations and aging factors can compromise structural reliability and reduce the service life for continuous satisfactory operation of service bridges in the future. Accurate prediction of bridge functionality relies on reasonable models of bridge strength and applied loads, and time-dependent reliability assessments can be used to gain a reliable understanding of bridge conditions so that appropriate solutions can be found. In this work, the reliability of bridges under harsh conditions was studied using time-variant and time-invariant reliability models in which both load and resistance are considered as time-dependent parameters. Combinations of the condition rating and time-dependent load were used to gain accurate insights into the degradation of the structural resistance of existing bridges. The results of this study showed the significant impact of aging and the influence of traffic loads on the service life of both national highway bridges and rural road service bridges. These observations could be used to devise appropriate planning strategies and plan rational decisions to ensure bridge safety in the future.