Durability Evaluation Of Existing Concrete Bridge In Cold And Drought Area Based On Variable Fuzzy Sets Theory

When the concrete bridge has been used in our daily life, the main reason which made the bridge fail in advance is the durability of the concrete. There are many factors that contribute to the durability of the bridge, including work environment, traffic volume and material defects, etc. The work environment which is one of the important factors can made the durability of existing concrete bridge different in different regional. Comparing with the ordinary regional, the cold and drought area is filled of the complex and bad climatic condition, of course, the durable problem of the bridge structure in the regional is also serious. It will not only seriously hinder the smooth running of traffic system, but also bring immeasurable loss to the national economy and people’s property safety, when the existing concrete bridge meets the durable damage. So, it is urgent to solve the durable problem of the existing concrete bridge in cold and drought area, and the key to solve this problem is the reasonable evaluation to its durability.In this paper, the author chose the durability of existing concrete bridge as the object and built the evaluation index system of the durability of existing concrete bridge durability in cold and drought area, the basic factors that contribute to building the evaluation index system include the existing concrete bridge durability evaluation theory, combination of the features of the durability of bridges in cold and drought area, analysis the factors which can influence the durability, and follow the principle of the establishment of evaluation index system. According to domestic and foreign standard of the durability of existing concrete bridge and the relevant norms, the existing concrete bridge durability evaluation level and evaluation index of each decision level in cold and drought area have been determined.According to the comparison of different method of weight and evaluation, the variable fuzzy is chosen as the main method of the evaluation model which is pointed to evaluate the durability of existing concrete bridge durability in cold and drought area, at the same time the evaluation index system of the durability of existing concrete bridge durability in cold and drought area is also an important factor, meanwhile, the process about how to use it has been introduced carefully. In this model, using the AHP to determine weights of evaluation index, introducing the variable fuzzy sets theory to be the body, through the new combination of the method try to complete the evaluation of the durability of existing concrete bridge in cold and drought area. AHP can combine qualitative analysis with quantitative analysis, and get accurate weight. When the variable fuzzy sets theory solves complex problems, it can be flexibly and determine different levels of assessment interval based on different types of evaluation index, and brings the quantitative index of the measured values in evaluation, makes the evaluation results more in line with the actual situation.According to specific engineering examples can verify feasibility and validity of the model. Through the example analysis, we can get that using the model established in this paper to evaluate the durability of concrete bridges in cold and drought area is completely feasible, the result can reflect the status of the durability of bridge, which can help to make the corresponding remedial measures solve the problem of durability, then ensure the safety of the bridge.