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Increased temperature and carbon dioxide concentration caused by climate change will aggravate the creep shrinkage and structural durability of concrete bridges. Overloading also has a great impact on the time-dependent reliability of existing bridges. This research paper analyses the time-dependent reliability of bridges based on climate change and overload. By improving the concrete carbonation model and referring to the B4 model of concrete creep, the effects of ambient temperature and humidity on concrete under different emission-reduction scenarios were considered. At the same time, given the serious problems of vehicle overload in China, combining different overload scenarios with climate change led to the establishment of a time-dependent reliability model for precast-concrete bridges. The results showed that as the overload rate increased, the time-dependent reliability degradation rate of a case study bridge accelerated. Under the scenario considering both high greenhouse gas emissions and the maximum overload rate, the service life of the case study bridge decreased to 50% of its design life. [ABSTRACT FROM AUTHOR]

China has many bridges in a vulnerable condition, and strengthening is crucial to guarantee their service life and performance. However, environmental impact is rarely considered in the maintenance of reinforced concrete structures. Moreover, considering the effects of vehicle overload and the external environment remains difficult. To solve these problems, the life-cycle reliability and induced environmental impact of strengthening bridges with bonded carbon-fibre-reinforced polymer under different external environmental conditions and overload scenarios were studied using Monte Carlo sampling, first-order second moment and life-cycle assessment methods. A simply supported reinforced concrete T-beam was selected as a case study. The results indicated that the external environmental conditions contributed significantly to the polymer strengthening effect, and polymer plates contributed more to reliability than polymer fabric. In overload scenarios, plates were more suitable for strengthening than fabric. When annual environmental impacts were considered over time, life-cycle maintenance plans with plates were better than with fabric, and environmental impacts were sensitive to the discount rate. [ABSTRACT FROM AUTHOR]