Research On The Safety Evaluation Of Existing Building Based On Variable Fuzzy Sets Theory

With the development of urbanization in our country,the population of cities has been exploding and the urban scale has been extending rapidly with a lot of buildings springing up every year. And people start to pay more attention to the safety and amenity of the houses after their basic living conditions have been met.The security circumstances of existing buildings are not only closely related to people’s life, but also have an important effect on the national development and social progress. Therefore, it has a great realistic significance to probe into the evaluation of the security circumstances of existing buildings. The study aims to provide a scientific and reasonable method for the safety evaluation work of existing buildings. Application of this method can evalue the level of security state of existing buildings, so that home owners or managers can understand the security state of the house timely and make appropriate responses based on the evaluation results to reduce unnecessary loss of property.To begin with, this paper will conduct an analytical study according to the current situation of safety evaluation from home and abroad and combine with China’s Standards and Specifications, such as “Standard for Appraiser of Reliability of Civil Buildings ”,“Evaluation Standards on the Performance Technology ”and“Standard for Appraisal of Dangerous Buildings ”and refer to the relevant documents to study the main factors affecting the safety of buildings, establish a safety evaluation system for exiting houses and determine the weight of each index. In the process of determining index weight, since the conventional subjective weighting methods used to determine the index weight data mostly derives from the experience of experts and the evaluationresults depend too much on expertise judgment, the evaluation results tend to have a high degree of subjectivity; The original dates of the objective weighting method are obtained from the actual evaluation index in the process of evaluation and it determines a higher weight precision with the actual situation of the evaluation objects being neglected sometimes. So the results are difficult to give a clear explanation. Based on the above description of the advantages and disadvantages of subjective and objective weighting method, this paper adopt the method of combining subjective and objective weighting method to empower in order to make more reasonable and accurate weights of evaluation indexes.Secondly, based on the evaluation index system,the theory of variable fuzzy will be introduced to this paper and this paper will establish the buildings safety evaluation method based on variable fuzzy theory. This method combines qualitative evaluation with quantitative evaluation to evaluate the field measurement of indicators by using actual measurement dates. As for the part that cannot be measured,the evaluation will be done according to the scoring results of experts and combine quantitative evaluation with qualitative evaluation into the same sort of safety evaluation method, which can avoid their shortcomings and make safety evaluation results more objective. At the same time, we can get the evaluation results under different parameters combination and make the evaluation results more accurate by the combination of the model parameter transformation.Finally, on the basis of theoretical research, this paper will prove the effectiveness and scientificity of the proposed evaluation method by using the safety evaluation model based on variable fuzzy theory and taking a trainees’ apartment of a hospital in xi ’an as an example.