Evaluation And Application Of Health Status Of In-service Concrete Girder Bridge In Alpine Permafrost Region

As an important transportation infrastructure in China,bridges undertake the key work of connecting the traffic area of road network.Affected by many factors such as service life,natural environment and service environment,bridge materials appear natural aging,structural strength,stiffness,stability and durability also change,and many diseases appear.Especially in China’s alpine and permafrost regions,due to the harsh natural environment characteristics of high cold,high temperature difference,strong solar radiation,long sunshine time,frozen soil and so on,the existing concrete beam bridges in this region appear more complex diseases than those in ordinary regions.Therefore,the health assessment of existing concrete beam bridges in China’s alpine and permafrost regions can provide reference for the existing concrete beam bridges in this region It can provide theoretical basis for the management,maintenance and repair of concrete beam bridge,and better guarantee the safe operation of existing concrete beam bridge in this area.In this paper,firstly,the connotation and method of health assessment of existing concrete beam bridges are expounded,and the applicability of fuzzy matter-element extension theory to health assessment of existing concrete beam bridges is analyzed.This paper investigates and studies the natural environment characteristics,highway traffic conditions and the diseases of the existing concrete beam bridges in the alpine permafrost region,and analyzes the generation mechanism of the main diseases.On this basis,combined with the structural characteristics of concrete beam bridge,referring to the relevant national and industrial standards and specifications,the health status evaluation index system of concrete beam bridge in service in Alpine permafrost area is established from the five aspects of concrete beam bridge material condition,appearance condition,frost resistance performance,natural vibration frequency and load influence,and the quantitative method and grading evaluation of each health status evaluation index are formulated Set the standard.G1 method and coefficient of variation method are used to determine the subjective weight and objective weight of each health assessment index.The "multiplication" integration method in combination weighting method is used to combine the subjective weight and objective weight of each health assessment index to determine its comprehensive weight,so that the evaluation index weight can reflect the subjective preference of the evaluator and maintain objectivity.Based on the fuzzy matter-element extension theory,the health status evaluation model of existing concrete beam bridge in Alpine permafrost region is established.The overall health status,appearance status,material status,frost resistance and traffic condition of existing concrete beam bridge are evaluated by making full use of the measured data and grading standards of each health status evaluation index.The calculation process is simple and the evaluation results are intuitive and accurate.Finally,the health status evaluation index system and evaluation model of the existing concrete beam bridge are applied to the actual engineering case to evaluate the health status of an existing concrete beam bridge in the alpine permafrost region.The evaluation results are consistent with the actual situation of the existing concrete beam bridge,which verifies the practicability and practicability of the established health status evaluation index system and evaluation model The feasibility and accuracy can provide a theoretical basis for the management,maintenance,repair and other decisions of the existing concrete beam bridges in this area.