The Research And Application Of The Fuzzy Synthetic Assessment Method For Health Condition Evaluation Of Bridges Based On AHP

Bridges is one of the most important constructions in highway transportation system. Subjected to the increasing change of the environment and the aggravation of the traffic, most of the existing bridges have degenerated. So the requirement of reinforcement and maintenance for the existing bridges is urgent. It is of great social significance and economic values to evaluate the health condition of existing bridges, which helps to ensure the security of bridges, decide the strategy of repairing and maintenance scientifically, and assure the traffic artery smoothly.In this paper, the technique of fuzzy synthetic assessment is introduced to the bridge assessment based on AHP (analytic hierarchy process). Then the application research of the bridge health assessment is demonstrated:1. Superiorities of the AHP method for evaluating the health condition of bridges are discussed in detail. Hierarchy evaluating systems for Cable-Stayed bridges and Arch bridges to classify the complex evaluating indices is set up.2. Based on AHP method, fuzzy synthetic assessment method for health evaluation of bridges is proposed. Fuzzy index can be got in the approach. The interval number judgment matrix is constructed applying uncertain AHP. To get the weight domain an optimal single-object model for calculating optimal weight is used and overall optimal searching is performed with genetic algorithm.3. The health conditions of Dong Tinghu Bridge which is a Calbe-Stayed bridge and Wu Chaohe Bridge which is an Arch bridge are evaluated using the method proposed. First, the evaluating models of the bridges are established. Then, a criterion for each judgment is given according to the standard or regulation in the bridge domain which divides the structure state into five categories: good, fairly good, slightly bad, bad and dangerous. Trapezoid membership function is used to determine the parameters of each judgment and the fuzzy evaluating indexed are obtained. Last, using the fuzzy synthetic assessment the overall health condition of the Dong Tinghu Bridge and Wu Chaohe Bridge are evaluated.