Multiple Layer Fuzzy Evaluation for Existing Reinforced Concrete Bridges

The principal objective of this paper is to set up an evaluation multiple layer fuzzy method model for evaluating the damage stage of existing reinforced concrete bridges. After establishing the detailed evaluation supportability and antiseismic ability of existing bridges items, the fuzzy mathematical theory is adopted to evaluate the damage state of any member of an existing bridge. The damage state of any member of an existing bridge is systematically and completely composed as an evaluation model of multiple layer fuzzy mathematics. The evaluated results may be used for the safety index and reference index for repair or reinforcement in existing bridges. In addition, the evaluated results may also be used as a design reference for service life in future bridge building. The evaluated model may be divided into the degrees of grades I, II, III, IV, and V, which are described as nondamage, light damage, moderate damage, severe damage, and unfit for service, respectively. Using the proposed model, the Huey-tong bridge, Jzyh-chyang bridge, Ay-gwo west road viaduct, and old Hwan-nan viaduct in Taipei were chosen for evaluation. The evaluated results of the present investigation indicate that the order of repair and reinforcement is the Ay-gwo west road viaduct, Huey-tong bridge, old Hwan-nan viaduct, and Jzyh-chyang bridge. Thus, the multiple layer fuzzy method appears the advantage for evaluating the damage of existing reinforced concrete bridges.