Abstract: To address the problem that traditional safety assessment methods for the metal structures of power construction crawler crane mostly rely on single weighting or simple weighting and are struggle to integrate both inspection data and expert experience, this paper proposes a metal structure safety assessment method based on combined weighting and variable fuzzy sets. Firstly, a multi-level evaluation index system including the crawler chassis, frame, boom, jib, hook, and slewing ring is established. Secondly, an interpolation scoring method is used to determine the indicator scores for strength, stiffness, cracks, deformation, corrosion, etc., and a membership degree matrix is constructed. Finally, the structural safety grade is determined by integrating subjective and objective weights and combining with variable fuzzy set theory. Taking a crawler crane as an example, the traditional single weighting method yields a grade characteristic value of approximately 2.24 and the proposed method yields a grade characteristic value of 1.61, which is about 28.1% lower than that obtained by the traditional method and more consistent with the on-site inspection findings. The results show that the proposed method can improve the accuracy of the metal structure safety assessment of crawler cranes, and can provide a reference for equipment inspection, maintenance, and risk management.

Key words: power construction crawler crane, metal structure, safety assessment, combined weighting, variable fuzzy sets