APPLICATION OF THE UNCERTAIN ANALYTICAL HIERARCHY PROCESS IN COMPREHENSIVE PERFORMANCE EVALUATION OF EXISTING CONCRETE RAILWAY BRIDGE

摘要

During the life-cycle of the concrete bridges, it is inevitable to be degradated in different degrees because of the inside and outside factors. Generally speaking, the longer the service period of bridge is, the worse its deterioration is. In China, most railway bridges have been built for 50 to 80 years, and the deterioration of them is increasing, some of them are even worse. Therefore, it is indispensable to inspect the existing concrete railway bridges for determining their condition. The current conditional assessment of railway bridges, however, is simple evaluation and qualitative analysis for each component of the bridges, and there is no appropriate integrative assessment system up to now. In this paper, an integral assessment model and the synthetic grading level for existing concrete railway bridge is figured out based on uncertain analytic hierarchy process. Aided by some new theories in mathematics, uncertain analytic hierarchy process (UAHP), set-valued statistics, barycenter decision theory and fuzzy evaluation, a corresponding method of conditional assessment for existing railway concrete bridge is given. Different with the certain judgment method, the uncertain judgment makes experts express their opinions more flexible in forming the judgment matrix. The real state of bridges can be described more exactly and the creditability of assessing results can be improved by this way. Meanwhile, considering the judgment level of experts, weights of them are introduced for decreasing the uncertainty of the assessing results. Then combined with group judgment theory, the subjective ingredient of judgment would be cut down, which makes the judgment more objective. The assessing result is quantitatively figured by the total deterioration, which reveals not only the degree of severity but also the quantitative relations. Therefore, the same scale bridges can be discriminated by the degree of total deterioration, and workload of maintenance can be shown by this to certain extent. The presented assessment method is proved feasible and reasonable through application to the bridges.