Research On Safety Inspection And Reinforcement Scheme Optimization Of Existing Large-span Steel Structures

With the rapid development of space structure forms in China,large-span steel structures have been widely used for their advantages of large-span,good seismic performance,and fast construction speed.In the normal use stage of existing large-span steel structures,due to the combined effects of environmental erosion and material aging and other factors,the resistance of the structure itself will gradually decay,and the damage caused by these factors will accumulate.When the limit state of the structure is reached,it will cause certain engineering accidents.Therefore,it is of great significance to carry out safety inspection and identification of the existing large-span steel structure,and to strengthen and repair the damaged structure to ensure the safety of the structure during use.The research on the identification and reinforcement of existing steel structures in China has achieved certain achievements under the study of relevant scholars.However,most of the choices of damaged structure reinforcement schemes rely on engineering experience.Few experts systematically study the selection of reinforcement schemes in terms of economy,technology,and society.In view of this,this thesis aims to provide rational scientific tools for decision makers and make a reasonable and effective judgment as the foothold.In order to avoid blind reinforcement of damaged structures and maximize the performance of reinforced structures.In this paper,on the premise of reviewing and analyzing a large number of relevant documents and materials,combined with specific practical projects,the research work on the optimization of existing large-span steel structure reinforcement schemes is carried out.The main research contents are as follows:(1)Conducted a systematic study on the related theories of inspection and identification and reinforcement and repair of existing steel structures.On this basis,the detection technology of large-span steel structure is discussed.And systematically analyzed the characteristics and applicability of commonly used reinforcement methods to provide a reference for the selection of later reinforcement methods.(2)This paper uses the mathematical methods such as importance index and coefficient of variation and Delphi method to establish the optimal index system of the existing large-span steel structure reinforcement scheme.Group decision-making group decision relative entropy aggregation method and improved entropy weight method are used to assign weights to each index to avoid defects caused by single weighting.The vertical distance theory is introduced to improve the traditional TOPSIS method,and the optimal model of the existing large-span steel structure reinforcement scheme based on the improved TOPSIS method is established.(3)Taking a large-span steel grid reinforcement project as an example,two models are used,namely,the traditional TOPSIS method and the improved TOPSIS method to establish a reinforcement scheme optimization model,and the four reinforcement schemes in this case are respectively optimized and decided.The calculation results are compared and analyzed to verify the reasonableness and effectiveness of the optimized model of the reinforcement scheme established by the improved TOPSIS method.The finite element software Midas/gen is used to verify and analyze the reinforcement effect of the best plan decided,and further demonstrate the feasibility of the reinforcement plan from a technical level.