Analysis Of Masonry Farmhouse Structural Reliability Identification Based On Fuzzy Comprehensive Evaluation Method

In rural areas of China,masonry structure is a widely adopted form of construction,which mainly uses raw materials such as bricks,stones and mortar.However,due to its own defects,such as relatively low strength and toughness and insufficient seismic performance,it is vulnerable to natural disasters and needs to be maintained and renovated.In order to solve the above problems,this thesis constructs a fuzzy comprehensive evaluation model for the structural reliability of masonry farmhouses based on the current house structure reliability identification standards and the structural characteristics of masonry farmhouses using fuzzy comprehensive evaluation theory.The calculation ability of SPSS was used to solve the weight of each level of the evaluation model and to evaluate the structural reliability of masonry farmhouse.Meanwhile,the accuracy and reliability of the evaluation model were verified by applying the evaluation model on masonry farm houses in a village and town in Anhui Province and comparing the evaluation results with those of the traditional evaluation method.The main research findings are as follows:（1）The nebulous comprehensive judgment model for structural reliability of masonry farmhouses was successfully constructed based on the current Reliability Appraisal Standard for Civil Buildings（GB50292-2015）and the structural characteristics of masonry farmhouses in China.The multi-level indicators and corresponding criteria of components,structural systems and evaluation units were carefully divided,among which,for foundation foundation,settlement difference of adjacent pile foundation,settlement rate,settlement crack and influence on upper load-bearing structure and enclosure structure were selected as judging indicators,corresponding to four safety judging levelsA_su,B_su,C_su andD_su and three serviceability judging levelsA_ss,B_ss andC_ss,respectively.（2）In the process of fuzzy comprehensive judgment,the reliability appraisal criteria were fuzzified by introducing a certain physical quantity u to apply the ridge-shaped affiliation function,transforming the quantitative index into a functional form and numericalizing the qualitative index.At the same time,the weights of masonry farmhouse in each reliability level index were determined,in which the weight coefficient matrix of safety index of the three structural systems was[0.1781 0.6432 0.1787]and the weight coefficient matrix of usability index was[0.4134 0.3605 0.2261].（3）The reliability of a masonry farmhouse in Anhui Province was evaluated by using the constructed fuzzy comprehensive evaluation model.The corresponding evaluation set was constructed based on the results of on-site structural inspection and the rating criteria.The judgment matrix was calculated by synthesizing with the weight coefficient matrix,in which the safety rating matrix of the farmhouse was[0.397 0.141 0.43 0.032]and the serviceability rating matrix was[0.034 0.76 0.206].The evaluation results of each level were rated according to the asymmetric closeness principle,in which the structural safety rating of the farmhouse wasC_su,the serviceability rating wasB_ss,and the reliability appraisal rating was III.And by comparing and analyzing the rating results with those of the traditional evaluation method,the comprehensive reliability evaluation results of this farmhouse are all consistent at level III,while in terms of the usability rating,the traditional evaluation method is rated at levelB_ss and the fuzzy comprehensive evaluation result is rated at levelC_ss.At the same time,there are some differences between the subunit and subassembly rating results,in which the safety and serviceability of the enclosure system structure are lower than those of the traditional judging method,which are in theC_u orC_s grade.The results reveal the conservatism and limitations of the original judging method and verify the accuracy and reliability of the judging model.