Normal cloud model theory-based comprehensive fuzzy assessment of wooden pagoda safety.

• It's the first time to apply normal cloud model into wooden pagoda safety assessment. • Two-way mapping of the "quantitative description-qualitative concept". • A four-level safety assessment index system. Currently the safety assessment of wood structure ancient buildings is mainly qualitative description, ignoring accurate quantitative calculation, and there are uncertain factors such as fuzziness and randomness that affect the results in the assessment process. Therefore, based on the cloud model theory of transformation between qualitative and quantitative uncertainties, this paper proposes a normal cloud model-based safety assessment approach for the protection research of wooden pagoda. A multi-level assessment system combining qualitative and quantitative indexes is constructed, and the comprehensive weight of the evaluation indexes is determined by combination weighting method. And combining with the scoring of evaluation indexes through quantitative analysis of point cloud, qualitative evaluation of experts, and published high-level papers, the comprehensive evaluation cloud model is constructed. According to the standard grade division, the criteria cloud model is constructed. And safety performance grade is determined by comparing the cloud similarity between the two clouds. Then this paper sets Yingxian wooden pagoda in China as an example, safety performance is quantified under this approach to determine its safety performance grade. The results show that the pagoda is the closest to third grade, in a certain dangerous state and consistent with the actual situation. The method takes into account the randomness and fuzziness factors, which makes assessment process more comprehensive and objective, provides a research paradigm for the safety assessment of ancient wooden buildings. [ABSTRACT FROM AUTHOR]