The fuzzy nearness between A and B is defined research use only by(A,B)=12[A?B+A?B],(10)where (A, B) is the fuzzy nearness between A and B. 0 �� (A, B) �� 1; the bigger (A, B) is, the better the nearness between A and B is.(2) Approaching Principle. Given A1, A2 An F(U) are the fuzzy sets. For fuzzy set B, if i 1,2,��n, (B, Ai) = max 1��j��n(B, Aj), then the nearness between Ai and B is much better, and fuzzy set B can be classified into fuzzy set Ai.3. Technical Route of Bridge Condition Evaluation Using Fuzzy ClusteringThe technical route used in this paper for condition evaluation of bridge by fuzzy clustering is shown in Figure 1.Figure 1Calculation process of bridge condition evaluation based on fuzzy clustering and field data.4. Fuzzy Clustering-Based Method for Bridge Condition Evaluation4.1.

Construction of Index System for Bridge Condition EvaluationIn the process of condition evaluation, the index system must scientifically, rationally, and objectively reflect the actual working status of the bridge. The index system for medium and small span bridge is determined based on the principle of integrity, simplicity, objectivity, and representativity in this paper, and it is shown in Figure 2.Figure 2Index system for condition evaluation of bridge superstructure.4.2. Construction of Evaluation System Based on Fuzzy ClusteringThe relative depth of carbonation calculated by (11) is used as evaluation index for degree of concrete carbonationCd=xcx,(11)where xc is the average depth of carbonation for bridge members, x is the average thickness of the reinforced protective layer.

Relative value of the protective layer thickness calculated by (12) is treated as evaluation index of protective layer thickness parameterPt=pmpd,(12)where pm is measured value, while pd is design value.The evaluation index for distribution situation of steel bar is shown in (13). The spacing between the rebars can be measured through electromagnetic induction technologySd=smsd,(13)where sm is the measured value for steel bar spacing, while sd is design value.The percentage of chloride ion content in cement content is used as evaluation index of chlorine ion parameters; it is denoted by Cl.The evaluation index for concrete strength is calculated byKbm=RimR,(14)where Rim is average value which can be measured by core testing, while R is the design strength of concrete.Minimum value of steel corrosion Dacomitinib potential is treated as evaluation index of steel corrosion parameters; it is denoted by Rc.The percentage of deviated measured points in the total points (LR) is used as evaluation index for longitudinal smoothness.The percentage of offset value that exceeds ��0.