Rotating Cumulative Sliding Construction Monitoring And Dynamic Response Analysis Of Large-Span Spatial Spoke-Type Chord-Supported Truss Structure

The large-span spatial spoke-type chord-supported truss structure is a new type of large-span prestressed structure.The structure is composed of an upper spoke-type truss and a lower string cable system.A self-balanced system is formed between the upper rigid structure and the lower flexible structure.Cooperative work,complementary advantages,with strong leaping ability,high carrying capacity and good stability.However,as a new type of large-span prestressed structure,the structural forces during the construction process are complex,the structural safety performance requirements during the construction phase are relatively high,and the dynamic performance research of the structure after completion cannot be ignored.In this paper,a practical project is taken as the research object.Firstly,the finite element software is used to simulate and analyze the construction process of the long-span structure,and the results are compared with the monitoring results to clarify the actual stress state of the structure in the process of construction slip.Secondly,the time-history analysis method is used to analyze the seismic response of the main structure after construction.The main contents and achievements are as follows:(1)Use finite element software to analyze the force state of the structure during the construction phase,and obtain the deformation and internal force of the structure during the sliding construction phase.The simulation results show that the deformation and stress of the main pavilion during the sliding process meet the design requirements,and the variation trend is gentle.The maximum displacement is the vertical displacement of the lower string of the middle truss,and the maximum stress occurs at the vertical ventral bar of the outer ring truss,the connection of the lower string of the central ring truss and the radial inverted triangle truss,the ventral bar and the upper chord of the central ring truss.The maximum displacement and deformation increased first and then decreased.(2)Develop a monitoring system and construction monitoring scheme based on the simulation results of the structural stress state in the sliding construction stage,select a total of120 stress monitoring points and 66 displacement monitoring points in 6 representative measurement areas to monitoring construction,and screen the monitoring data.The analysis results of the monitoring data show that the structural deformation and force have not exceeded the control value,and the structure is in a safe state during the entire sliding construction process.(3)Based on the comparison results of the finite element theoretical calculation values and the monitoring values of the structure,the variation trend of the stress of the bar and the joint displacement during the sliding process is analyzed.The results show that:Structural deformation and stress in the process of sliding construction monitoring values and calculated values,although there are some differences between the node displacement direction and bar stress the nature of the monitoring results and the calculation results are basically identical,and the same change trend,verify the feasibility of sliding construction scheme,the correctness of the finite element simulation,and the applicability of the monitoring programme.The structural force changes greatly at the beginning and end of the sliding construction,but the monitoring data of the structural displacement and stress obtained by the monitoring system during the entire construction process are within the allowable range of the specification,and the entire construction process is safe and reliable.(4)Use the finite element software to analyze the structure of the main building after the project is completed.The analysis results of the natural vibration characteristics of the structure show that the rigidity of the main building structure is evenly distributed,the natural frequency is relatively dense,and there is no obvious jumping point in the curve with the order.The first 10 modes of the structure are mainly vertical vibration and bending vibration,in addition to torsional vibration.El-Centro wave,Taft wave and artificial wave 3D seismic wave are selected to analyze the seismic response of the main structure under the action of frequent earthquakes,fortified earthquakes and rare earthquakes.The simulation results show that: The main structure is still in the elastic working state under the rare earthquake action of three seismic waves,and the maximum joint displacement and cable force are both within the safety limit.The safety performance of the new large-span space hub-and-spoke truss structure under earthquake action is verified.