Research On Analysis And Design Method Of Super-long Span Truss String Structure

With the emphasis on environmental protection and sustainable development,it is an inevitable trend to remodel the storage structure into enclosed raw material yard.The optimization analysis and design of superlong-span cylindrical structures can create huge value,and the stability of long-span truss string structures is an important factor controlling structural safety.Therefore,the research on optimization method and overall stability of super-long-span truss string structures have a significant value for structural safety and structure economic performance.This paper focuses on the super-long-span truss string structure.A program for generating three-center circle prestressed truss model is developed.Combining numerical simulation analysis with engineering cases,a parametric iterative optimization method is sort out.The application of parametric optimization method in super-long-span cylindrical structures and the selection principle of key parameters are analyzed based on three cases of super-long-span truss string structures.Based on the sensitivity analysis of the parameters,the parametric optimization method especially for truss string structure is proposed by ranking the importance of the parameters.This paper also analyses the overall stability of cylindrical truss string structures with different spans under full-span live load and half-span live load,and the influence of initial imperfection on the structural stability is discussed.All the results are verified by an engineering case.The parametric optimization method for truss string structure and the conclusion about overall stability proposed in this paper can provide guidance for the analysis and design of such truss string structure.The main conclusions of this paper are as follows:(1)The parametric optimization method suitable for truss string structure can effectively improve the efficiency of optimization and reduce the steel consumption.(2)The thickness of the main truss has a greater impact on the economic performance of the structure and should be considered as a sensitive parameter,compared with other parameters such as the width of the truss and the prestress value of the cable.(3)Taking the static instability mode of ideal structure as the initial geometric imperfection of the structure has more significant influence on the overall stability of the structure than the consistent mode imperfection method recommended by the code.(4)Both half-span live load and wind load are not the control loads for the overall stability of such truss string structure,whereas the structural stability coefficient is usually lower under full-span live load.