钢筋混凝土桥梁的耐久性评估

On the durability evaluation of the reinforced concrete bridges

为解决现阶段钢筋混凝土桥梁耐久性评估中所存在的步骤粗糙、程序简单、主观性较强等问题,基于我国《公路桥梁技术状况评定标准》、《公路桥涵养护规范》,确定出评价指标体系、分类等级界限及全桥不同等级下的结构综合性病况;并利用层次分析法、熵权理论确定各指标的主、客观权重系数,依据组合权重理论确定各因素的综合权重向量集,采用模糊学理论中的岭形隶属函数构造模糊评价矩阵,按照由底层向顶层逐层评价的顺序,构建了三层次三环节的桥梁耐久性模糊评估模型;然后根据最大隶属度原则确定桥梁耐久性状态等级,并为不同耐久性状态等级的钢筋混凝土桥梁提供了具体的解决整修措施;最后,结合实例检验该评价方法的科学性与合理性。结果表明,以3组检测数据样本为依据,评估所得实例桥整体状态均为Ⅱ级,与现场实际检测所得的评估结果一致。组合权重理论既能结合专家经验又能考虑现场实际情况,而模糊学理论能够与工程应用进行较强的结合,以此能减少主观评估、片面化、评价过于精简等问题;并且组合权重-模糊学理论综合评价方法思路清晰、客观性强、计算简单、评价结果能够详细给出不同结构部位的耐久状态。

This paper has been trying to identify and determine the evaluation index system based on the state stipulated ＂Technical Evaluation Standards for Highway Bridges＂ and ＂the Code for Maintenance of the Highway Bridges and Culverts＂ by overcoming the currently adopted blunt steps and simplicit procedures in addition to the over-dependence on the builder＇ s subjectivity so as to improve and heighten the durability of the reinforced concrete bridge in response to the up-to-date demands for modernization. In so doing, we have been making efforts in classifying and cate- gorizing the level boundaries and comprehensive structural conditions at the different managerial levels. Furthermore, we have also managed to identify and determine the comprehensive weight vector sets of each factor according to the combined weight theory by using the ridge-like membership function in a fuzzy theory, the analytic hierarchical process and the entropy weight theory to determine and resolve the subjective and objective weight coeffi- cients of each index. It is also based on the order from bottom to top that we have established the bridge durability evaluation model according to the principle of the maximum membership with the specific solutions provided for the reinforced concrete bridges of different durability levels. And, finally, the evaluation methods have been tested with the authentic case samples. The aforemen- tioned research results show that the bridge is based on the 3 sets of the testing data samples, while the overall state of the evalua- tion is Grade If, which is believed consistent with the actual test and evaluation results given by the expert experience with the actual situation and the fuzzy theory with the practical engineering application so as to overcome the subjective assessment, lop-sided over-simplified judgment. What is more, the combined weight- fuzzy theory comprehensive evaluation method enjoys the superior clear-cut ideas, strong reliable objectivity, simple-manner calculation, and detailed evaluation results. Thus, the durability of the different structural parts can provide a theoretical support for the grading of the reinforced concrete bridge structure and the maintenance protection availability so as to heighten its strong economic practicability and lead to brilliant technical significance.