Safety Assessment Method for Steel Arch Bridge Based on Optimal Weights and Fuzzy Theory

The safety status of in‑service bridges is affected by many factors and there are many evaluation indices. In order to effectively evaluate their safety status，considering the influence of multi‑source factors，a bridge safety assessment method based on the optimal weights and fuzzy theory was proposed. This method obtained the mechanical response of the corresponding monitoring points of the bridge under various preset cases through numerical analysis，and the safety level division standard of the bridge was determined according to the numerical calculation results and the current specifications. The membership function was introduced to establish the fuzzy evaluation vector of each index. Fuzzy analytic hierarchy process and entropy weight method were used to determine the subjective weight and objective weight for each index，and the optimal weight was obtained by combining preference coefficients. The safety level of bridge was determined by fuzzy comprehensive evaluation method according to the principle of maximum membership degree. Taking a steel arch bridge as an example，the safety levels under 24 preset cases were calculated. At the same time，according to the real‑time monitoring data of the bridge in one week，the dynamic safety levels of the bridge in this period were obtained. The results show that the assessment method can fully consider the influences of various subjective and objective factors and dynamically evaluate the safety status of bridge according to real‑time monitoring data.