| The beam string structure is based on the traditional rigid structure with flexible cable.and then the prestressed cable changes the mechanical performance of the structure at the same time.The form of beam string structure can meet the needs of various design forms,with high bearing capacity,and has been widely used in many large-scale projects such as exhibition hall,stadium,transportation hub hall,etc.With the continuous innovation of the form of beam string structure,the construction difficulty will be more and more.It is of great practical value to carry out the simulation analysis and on-site monitoring of the construction process of the beam string structure,and to study the influence of local pouring concrete on the static and dynamic performance of the structure,so as to ensure the safety and quality of the structure.In view of the sensitivity of this kind of structure to wind load and the strong destructiveness of earthquake,it is very important to carry out static and dynamic analysis on the beam string structure.This paper summarizes the characteristics of the beam string structure and the research and application status at home and abroad.On the basis of previous scholars' research,taking the beam string roof of the main building of Yulin airport phase II terminal as the prototype,using Midas/gen finite element software to establish the beam string roof model,and carries out the construction process simulation analysis,structural parameter analysis,structural stability analysis and natural vibration characteristics analysis of the beam string structure and seismic response analysis.The main work of this paper is as follows:(1)This paper simulates the construction process of prestressed tension of the beam string roof structure,and compares the finite element analysis results with the construction site monitoring data.The simulation is used to guide the field construction,and the correctness of the simulation is verified by the field construction.The reason for the difference between the simulated value and the actual measured value is summarized,which provides a useful reference for the similar project tension construction in the future.(2)In order to further understand the mechanical properties of the structure,the number of struts,rise span ratio,vertical span ratio and other parameters of the structure are analyzed,and the effects of the changes of parameters on the deformation and stress of the structure are analyzed and studied.By comparing the ordinary steel box girder model with the local steel box girder concrete model,the results show that the local concrete pouring can inhibit the uneven arching of the structure.(3)Based on the linear buckling analysis of the roof model of the beam string structure,the lowest buckling mode of the structure under full live load is the vertical instability of the top chord beam,but the structure as a whole has a high anti instability ability.From the nonlinear buckling analysis of the roof model of the beam string structure,it can be seen that the increase of the initial geometric imperfection has little effect on the stability bearing coefficient of the structure,which shows that the structure is not sensitive to the change of the initial geometric imperfection.(4)Based on the analysis of the natural vibration characteristics of the structure,the time history analysis method is used to analyze the dynamic response of the beam string structure under the action of one-way and three-way ground motion.The time history response of the key nodes,braces and cables of the structure is compared and analyzed.The results show that the overall seismic performance of the structure is good,and the dynamic response of the structure under the action of three-way seismic wave is greater than that under the action of one-way seismic wave,and the horizontal displacement of local steel box girder concrete roof structure is larger than that of ordinary steel box girder roof structure. |
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