Study On Key Technologies For The Construction Of Super-large Span Fishbelly Cable Truss Structure

The super large span fish belly cable truss structure is a type of prestressed spatial structure system.Cable truss roof structures generally consist of a rigid compression outer ring connected to the central compression inner ring through radially arranged cable trusses.The tension of the cable truss is balanced with the pressure of the outer ring,forming a self balancing force system.This structural form has broad prospects due to its lightweight,beautiful appearance,and compliance with the concept of green development.The super large span fish belly cable truss structure is formed by the joint force of the cable and membrane,and the force of the cable and membrane is relatively complex,which cannot directly refer to mature design analysis and construction methods such as string supported dome and beam string.The background project of this article is the Lucille Stadium,the main stadium of the2022 World Cup.The main cable system of the roof adopts a super large span fish belly cable truss structure,which is rare in terms of scale and span both domestically and internationally.It is also the first application in large sports venues.Therefore,conducting construction process analysis and structural error analysis research on the super large span fish belly cable truss structure is of great significance for ensuring the safety of the structure during the construction process and meeting the acceptance standards and usage functions after construction is completed.This article compares and analyzes the forming methods of the main cable system of the Lucille Stadium roof,simulates and analyzes the entire construction process of the optimal method for cable forming,studies the stability scheme of the support rods during the construction process,and studies the impact of structural component processing errors and construction deviations on the structure,as well as the control standards and other key technologies,the main research content and achievements of this article include the following points:(1)According to the design data,this paper introduces the modeling process of finite Metacomputing analysis and BIM three-dimensional model modeling process,uses Midas/Gen software to establish the overall structural model for finite Metacomputing analysis,uses Revit software to establish the overall three-dimensional structural model,and introduces the construction simulation calculation and the methods and steps of realizing virtual construction based on BIM technology.(2)Three structural forming methods have been proposed.Three forming methods were simulated using BIMfilm software,and their technical feasibility,economy,and construction period were compared.Two methods were selected to continue finite element construction simulation calculations,and key parameters were obtained for comparative analysis.Based on the principle of forming method comparison,the overall lifting forming method of "lifting the ring cable first,then lifting and tensioning the radial cable separately" was finally determined.(3)According to the proposed optimal structural forming method,conduct simulation calculations throughout the construction process,study the impact of wind load and asynchronous lifting on the structure,explore the most unfavorable working conditions,and provide theoretical basis for actual construction control.According to the calculation results,it is believed that under the action of local wind loads and when there is a slight deviation in the lifting synchronization,the impact on the structure is controllable.The tension of the lifting device and the unbalanced force of the nodes can be controlled within the design requirements,verifying the high safety and reliability of the construction method.(4)In response to the high risk of instability of the support rods in the super large span fish belly cable truss structure,10 stability schemes for the support rods are proposed,and a comparison principle for the stability scheme of the support rods is formulated.Through finite element numerical simulation analysis of the 10 stability schemes for the support rods,the optimal stability scheme for the support rods is selected based on the comparison principle of "arranging four intersecting cables and two circumferential cables between adjacent cable truss support rods".(5)The control accuracy of structural errors and construction deviations is directly related to the shape of the structure.In this study,the error sensitivity of the super large span fishbelly cable truss structure was studied,and the effects of cable length error,strut length error,and construction deviation of the ring truss ear plate on the structure were analyzed,and error control limits were proposed.