基于层次分析法-隶属度理论的混凝土框架结构安全性模糊综合评价方法

Fuzzy Comprehensive Evaluation Method for Safety of Concrete Frame Structures Based on AHP-Membership Theory

现有规范、标准采用定性定量相结合的方法对混凝土框架结构的安全性进行评价,难以判定同安全等级结构的相对安全性。根据混凝土框架结构的受力特点,建立安全性评价层次模型,结合已有结构设计、检测、鉴定方面的规范标准,构建构件检查项目安全等级评价指标体系,基于隶属度函数理论建立检查项目综合评判矩阵,提出混凝土框架结构安全性三级模糊综合评价方法,设计主体结构安全性按现行鉴定标准评定为A、B、C和D级的工程算例,将分别采用本文方法、最大隶属度法和等级加权平均法进行结构安全性评价,并进行对比分析。研究结果表明:基于层次分析法(AHP)所建立的结构安全评价模型,能反映混凝土框架结构受力特点;采用德尔菲法确定因素重要程度模糊集,充分发挥专家集体智慧在评判中作用,能较好体现赋权公平性;以AHP层次模型、因素重要程度模糊集和构件检查项目综合评判矩阵为基础的模糊综合评价方法,可以量化评估混凝土框架结构安全性,与现行规范安全等级评定结果的吻合程度最高,构件层、子单元层和鉴定单元层的平均一致率分别为71.9%、91.7%和100%。

Existing codes and standards adopt qualitative and quantitative methods to assess the safety of concrete frame structures,which can hardly judge the relative safety of structures at the same safety level.According to the stress characteristics of concrete frame structures,this paper built a hierarchical safety assessment model,combined the existing codes and standards in structural design,testing,and identification to construct a safety grade evaluation index system for component inspection items,and established comprehensive evaluation matrices for inspection items on the basis of membership function theory.Moreover,it developed a three-level fuzzy comprehensive evaluation method for the safety of concrete frame structures.The engineering cases with the safety of the main design structure rated as A,B,C,and D according to the current identification standards were designed,and the structural safety was evaluated by the proposed method in this paper,the maximum membership degree method,and the weighted rank average method for comparative analysis.The research results show that the structural safety evaluation model based on the analytic hierarchy process(AHP)can reflect the stress characteristics of concrete frame structures.Using the Delphi method to determine the fuzzy sets of the importance of the factors can give full play to the collective wisdom of experts in the evaluation and can better reflect the fairness of empowerment.The fuzzy comprehensive evaluation method based on the AHP model,fuzzy sets of factor importance,and comprehensive evaluation matrices of component inspection items can quantitatively evaluate the safety of concrete frame structures.Moreover,its results can achieve the highest degree of coincidence with the safety grade evaluation results of current specifications,and the average consistency rates of the component layer,sub-unit layer,and appraisal unit layer are 71.9%,91.7%,and 100%,respectively.