Establishment and Updating of Nonstationary Resistance Deterioration Model of Existing Concrete Bridge Component

The focus of this research is the resistance deterioration behavior of existing concrete bridge components under the influences of environmental, material, and loading factors. To derive a more accurate resistance mathematical deterioration model of existing concrete bridge components, the Gamma process is firstly introduced to establish the original mathematical model by mathematical derivation according to the deterioration properties of concrete components. The updating procedure of the original mathematical model is then provided by incorporating the actual deterioration conditions, in which the key point is the determination of deterioration conditions at a specific moment. Based on the physical data measured from field inspection, a fuzzy evaluation method of the deterioration coefficient is developed by combining a nondeterministic analytic hierarchy process (AHP) and real-coded–based genetic algorithm (RGA). The accuracy of the developed fuzzy evaluation method is validated through loading tests of experimental beams. The results show that the developed fuzzy evaluation method is accurate and the calculated deterioration coefficients can be used in the updating of the original mathematical model. In the former, an existing concrete bridge is taken as the prototype bridge to conduct a case study. It is found that the proposed framework can be successfully used in the establishment and updating of resistance deterioration model of existing concrete bridge component. The updated mathematical model is more accurate than the original mathematical model in the description of the resistance deterioration process considering the incorporation of the actual deterioration conditions in recent years.