Reliability evaluation and multi-objective maintenance planning optimization of deteriorating PSC box-girder bridges

The reliability evaluation and maintenance planning optimization of deteriorating PSC box-girder bridges in service are the basis for its sustainable development. In this article, first, the scale of fluctuation of concrete compressive strength is estimated based on the measured data of three 36-year-old components. Then, the reliability evaluation model of deteriorating concrete bridges considering the influence of prestress loss and spatial heterogeneity is established. Moreover, the assessment method of maintenance cost and the impact of maintenance activities on the environment are introduced, and the multi-optimization method of maintenance planning for degenerating concrete bridges. Final, the proposed methods are applied to a three-span PSC box-girder bridge. The case analysis results show that reasonably increasing the implementation numbers of PM is conducive to achieve the sustainable development of deteriorating PSC box-girder bridges. The maintenance planning obtained without considering the non-stationary growth process of live load effect underestimates the sustainable development goals throughout the life cycle, especially the total CO2 emissions.