The Reliability Assessment Of The Existing Concrete Bridge Based On The Extension

With the vigorous development of world bridge enterprise,Domestic and foreign construction of the bridge are increaseing by leaps and bounds in the number,complex and diverse in structure.However,bridge design,the design is unreasonable,the construction quality control is bad,and in the late use of the process,there are many factors that lead to the reliability of the bridge.the cause of the bridge is characterized by a large number of technical conditions.Therefore,we are faced with a difficult bridge detection,evaluation,strengthening and maintenance work.In this paper,on the basis of the research results of bridge evaluation both at home and abroad,according to different structure forms of bridges,a more accurate and suitable method for evaluating the reliability of the bridge is prosed,the extension evaluation method.Specific aspects of the following work:(1)The basic principle,contents and methods of extenics is introduced,the extension theory is applied in the reliability evaluation of bridge.Bridge which is waited for evaluation is as the evaluation object,bridge reliability is divided into five grades according to the multilevel extension assessment results,and the evaluation grade and extension evaluation results is given for one-to-one correspondence.In order to understand and summarize the disease of the bridge,the field survey of nearly 200 bridges in Shenyang city was conducted,and the disease classification of each type of bridge was summarized.As a result,the reliability evaluation model of each bridge is established,and the foundation of bridge reliability evaluation is established.(2)In order to carry out the comprehensive evaluation of concrete girder bridges reliability,research results and the relevant specification are combined,analysis the influence of concrete girder bridges reliability factors.Effect of concrete girder bridges reliability evaluation index system is established.For each level index(bridge deck system,superstructure,substructure and ancillary facilities,reliability evaluation model is established.Application of extension evaluation method of each component of the extension evaluation.Finally,the system of bridge deck,superstructure,substructure and ancillary facilities extension evaluation summary results are summarized.Further application of extension evaluation method is used to calculate the overall reliability of concrete girder bridges,and make the grade evaluation,make the comprehensive analysis of the evaluation results.(3)In order to carry out the comprehensive evaluation of concrete cable-stayed bridge,girder and tower,cable,the foundation and the pier,ancillary facilities are taken as first grade indexes,hierarchical model of reliability evaluation of concrete cable-stayed bridge is established,the AHP evaluation model for each level of evaluation index is established,the criteria for the classification of bottom assessment index is determined,the classical domain and joint domain are established.The reference correlation function theory is used to calculate the values of correlation degree,and multilevel extension assessment is carried out,the bridge comprehensive reliability level is given at last.(4)In order to carry out the comprehensive evaluation of concrete arch bridge,the upper structure and the lower structure are taken as first grade indexes,the upper structure including the main arch and arch,the lower part of the structure including piers and foundation and abutment.The most bottom evaluation criteria is determined,combined with the detection results of the engineering case of the Xiuyan territory of the Huanghuadian Bridge,the multi-level extension evaluation is carried out,which proves that the evaluation method is good for engineering application.Appropriate disposal methods are adopted for the evaluation results.(5)In order to carry out the comprehensive evaluation of concrete suspension bridge,concrete suspension bridge reliability evaluation hierarchy model is established at the component level,the criteria for the classification of bottom assessment index is established,extension evaluation method was applied to the example of the project of Fushun Tianhu bridge,multilevel extension assessment results show that the bridge reliability level for class III.According to the evaluation result with the scene actual situation,take the mesuares of replacing the slings,installing antiskid fixing cable and so on.As a result,the bridge reliability is greatly improved.