퍼지이론 및 의사결정방법에 의한 철근콘크리트교 상태평가

Abstract

This dissertation presents a assessment system used Fuzzy Theory and Analytical Hierarchy Process(AHP) for the deterioration and structural safety of reinforced concrete bridges. The system is capable of estimating the degree of global performance from visual inspection in regular inspection stage. The construction of the assessment system includes the selection of assessment items, the estimation of their importance, and the aggregation of individual criterion and their importance. The assessment items are classified into three categories, such as, upper structures data, base structures data, accessory structures data. And each category is composed of several performance items at lower levels. The grade of importance of assessment items are estimated from the concepts of importance and used in the conservative assessments, respectively. The importances are estimated by reflecting the interrelationship among assessment items from the belief and plausibility measures into the relative importance by the Analytical Hierarchy Process(AHP). The estimated results of assessment items and their weights are aggregated in stages in the framework of assessment items. Fuzzy theory showed good applicability as a quantitative assessment scheme by relieving extreme qualitative assessment and thus securing objectivity. The modular stepwise assessment facilitated efficient assessment and enabled to minimize the missing data problems. As a result of aggregation, the system provides state indices for the optimistic or conservative assessment, which are used as the criteria for refined inspections. When applied to the actually diagnosed bridge, the porposed system is capable of estimating the degree of global performance from visual inspection in regular inspection stage. The system provided similar results to those by experts. Furthermore, this system was able to provide a systematic and continuous management and a highly reliable estimation for those general engineers. From these results, it can be concluded that this system can be used as a component of maintenance and management scheme for the structural safety and systemization of maintenance and management activities in regular inspection of reinforced concrete bridges.

Keywords : Analytical Hierarchy Process(AHP), State Assessment, Fuzzy Theory, Reinforced Concrete Bridge.