Stress Analysis And Monitoring Of Arched Steel Tube Truss Structure During Jacking And Unloading Stage

With the development of economy and the advancement of science and technology,long-span space steel structures are increasingly used in engineering.With its light and high-strength nature,more and more complex structures with long spans and large spaces are constantly appearing.However,along with superior performance,it is a complex construction process and a higher quality requirement for its engineering.Once the structure is damaged or even collapsed during construction and assembly and welding,it will cause huge economic losses and even pose a threat to personal safety.In order to ensure the safety and reliability of the structural construction process,the long-span steel structure adopts the ground assembling and the overall jacking construction process.Therefore,it is essential to ensure the safety of the jacking construction phase.In this paper,the arched steel truss structure of the second phase reconstruction project of Harbin Station elevated station is taken as the research object.The numerical simulation analysis and real-time monitoring of the force state in the lifting and unloading construction stage are carried out.The actual monitoring data and numerical simulation are compared and analyzed.As a result,the differences under different unloading methods of such structures were investigated.The main research contents of this paper are as follows:(1)According to the design data of the second phase reconstruction project of Harbin Station,the finite element model of the arched steel pipe truss structure was established by ANSYS.According to the numerical simulation results,the important bearing members of the arched steel tubular truss structure during the jacking and unloading process are determined.At the same time,based on the actual engineering jacking and unloading construction scheme,the corresponding monitoring scheme is designed.(2)According to the mechanical characteristics of the steel strand used in the jacking and unloading process,it is simulated by the Link 180 unit.Based on the actual lifting and unloading construction scheme,the two different unloading processes are divided into multiple construction stages.Through the steady-state continuous load step analysis method,the stress state of the connecting rods under different unloading modes is analyzed and compared.The advantages and disadvantages of the two uninstall methods.(3)On-site real-time monitoring of the entire lifting and unloading construction process of the arched steel truss structure of Harbin Station was carried out.The working principle and related parameters of the grating fiber strain sensor and strain gauge used in the monitoring process were introduced,and the data acquisition was carried out.The installation of the system is described Combined with the numerical simulation results,the stress changes of the connecting rods during the two lifting and unloading construction processes are analyzed,and the reasons are explained.The guiding suggestions for the actual construction scheme are proposed.