The objective of this study is to develop methodologies to estimate and predict thefragility of deteriorating reinforced concrete (RC) bridges, and to identify the effect ofdesign and construction parameters on the reliability of RC bridges over time to assist inthe design and construction process.To accurately estimate the fragility of deteriorating bridge, probabilistic capacityand demand models are developed. In addition, to simplify the calculation costmaintaining accuracy, fragility increment functions are developed. The proposedfragilities account for model uncertainties in the structural capacity, demand models,corrosion models. Furthermore, proper account is made of the uncertainties in theenvironmental conditions, material properties, and structural geometry. To identify theeffect of design and construction parameters on the reliability of RC bridges, asensitivity and importance analysis is conducted. Sensitivity analysis for an examplebridge subject to corrosion is carried out to identify which parameters have the largestimpact on the reliability over time. This dissertation considers different combinations ofchloride exposure condition, environmental oxygen availability, water-to-cement ratios, and curing conditions, which affect the reliability of bridges over time. The developedmodels are applicable to both existing and new RC bridges and may be employed for theprediction of service-life and life-cycle cost analysis of RC bridges.
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