针对既有公路桥梁评价标准在大跨径桥梁状态评估方面的局限性,开展了斜拉桥的综合评估方法的研究.在现行公路桥梁技术状况评定标准基础上,增加部分斜拉桥特有要素以及长期监测数据,建立了一套新的斜拉桥综合评估指标体系.考虑传统加权计算方式易掩盖子指标之间评分差异大的状况,引入可信度,建立了斜拉桥多指标证据融合的综合评估模型:底层指标的评定标准采用分段线性模式,其基本可信度由隶属度和权重决定,模糊隶属度可由岭型分布函数计算得到;上层指标的可信度由一种改进的Dempster组合规则合成.以江苏省内某大跨径斜拉桥建成10 a后的定期检查内容为例,分别用规范的方法以及改进评估方法对比分析.结果表明,改进评估方法的结论与实际工程中缺陷和维修状况更为接近,评价所属类别更合理,且可信度集合相比单个数值更能综合地表达结构状态.%Due to the limitations of assessment on the state of long-span bridges based on of the existing highway bridge evaluation standards,the comprehensive evaluation method of cable-stayed bridges was conducted.On the basis of the current standards for technical condition evaluation of highway bridges,a new comprehensive evaluation index system was established by introducing of some special components and long-term monitoring data.Considering the traditional weighted calculation method is easy to cover the situations of the big differences among of the indexes,a comprehensive assessment model with multi-index evidences fusion was proposed based on the credibility.In this model,a piecewise linear criterion of the evaluation index was used in underlying layer firstly.The basic confidence was determined by the membership and weight,and the fuzzy membership was calculated by the ridge type distribution function.Secondly,the confidence of the upper layer was composed by an improved Dempster combination rule.A large span cable-stayed bridge in Jiangsu Province was taken as an example,and the standard method and the improved method were analyzed based on the periodic inspection reports during 10 years.The results show that the conclusions using the advanced method agree well with the actual defects and maintenance conditions.The evaluation category is more reasonable,and the confidence set could present the state of the structure more comprehensively compared to a single value.
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