Static And Stability Performance Research Of 800-Meter Super Large Span Cable-Stayed And Underneath-Cable Supported Mega Grid Structure

With the increase of structural span to thousand meter,the defect of the single structure is more and more obvious.This paper proposed a kind of cable-stayed and underneath-cable supported mega grid structure for super-large span structure,which is used to provide elastic support for rigid main structure with high strength of cable.The structure consists of tower,cable,cable stayed grid,underneath-cable,cable supported grid and supporting bar.In this paper,the following research work is carried out:(1)Propose a cable-stayed and underneath-cable supported mega grid structural systemBased on a cable-stayed and underneath-cable supported mega grid structural system which is proposed to super-large span structure,this paper have analyzed the composition and the principle of the basic force of the structure,described its modeling process and the basic assumptions and clarified its load value and load combinations.(2)The structural cable arrangement and initial prestress optimization are studiedReasonable cable arrangement and the contribution of underneath-cable are obtained by comparing the internal cable force.The inverse iteration method is applied to the formfinding process of the cables,reasonable distribution of cable initial pre-stress reduced the displacement of the structure in initial state.Research on prestressed cables shows that the amount of cables won’t be dramatic declined by decreasing the prestressing force,but structural stiffness will be reduced obviously.Compare the steel cables structural properties with CFRP cables at last.(3)static and stable properties of structures are studiedThrough the full stress design of the structure,this paper get a reasonable crosssection of the member,and under the given stress ratio the economic index of the structure is obtained.We get the deformation and internal forces of the structure under various working conditions by static analysis,and the rigidity checking of the structure prove that it satisfies the requirement of normal deformation.According to the analysis of the structural self-vibration characteristics,the self-vibration mode and period of the structure are obtained.In addition,the linear stability analysis and nonlinear stability analysis is also be carried out to find the ultimate stable bearing capacity of the structure.(4)Parametric analysisThe parametric analysis has be done,include the control stress ratio,rise span ratio,span of the cable supported structure,height of the tower and support pattern.The change rule has be summarized that how the parameter affect the performance of the structure.The reasonable data range of the parameter has be concluded for the father research.Results show that the cable-stayed and underneath-cable supported mega grid structure has a good mechanical properties,and its economic performance is acceptable,it can be an alternative scheme for super-large span structure.