Analysis Of Static And Dynamic Performance And Construction Process Of Long-span Cable-supported Of Concrete Beam Structure

The cable-supported of concrete beam structure is composed of concrete beam as the upper bending member,cable as the lower tension member,and the middle is composed of rigid struts.This structure system is simple in structure and reasonable in force,which can give full play to the respective advantages of flexible cable,rigid struts and concrete.This paper takes the long-span cable-supported concrete structure of a high school gymnasium as the research background,and uses large general finite element design and analysis software Midas Gen to establish the model,and the static performance analysis,natural vibration characteristics analysis,dynamic response analysis and construction process study are carried out.The main contents are as follows:(1)A single common long-span concrete beam finite element model was established,by changing the concrete strength grade,the number of struts,the size of the beam cross section,sag-span ratio and cable section size,studied in the combination of self-respect and prestressed load condition of bottom chord concrete beam static performance,and further studied as an important part of the anchor nodes of ear plate performance.(2)The multi-Ritz vector method is used to analyze the natural vibration characteristics of long-span cable-supported concrete structures.The natural vibration characteristics of long-span cable-supported concrete structures are summarized by changing the structural parameters such as floor thickness,concrete strength grade,prestress value and boundary conditions.(3)On the basis of the analysis of the natural vibration characteristics of the concrete structure,the time-history response results of the structure with different input seismic waves are obtained by inputting horizontal unidirectional,vertical unidirectional and three-directional seismic waves respectively,and the influence of different seismic actions on the mechanical properties of the long-span cable-supported concrete structures was comparatively analyzed.(4)The construction method of long-span cable-supported concrete structure is described,and the construction process is simulated,and the simulation results are compared with the measured results to provide reference for the construction of similar engineering structures.The main conclusions are as follows:1)The displacement,bending moment,strut stress and cable internal force of long-span cable-supported concrete beam structure are symmetrically distributed under the action of dead weight and prestress;In a certain range,increasing the vertical span ratio can improve the mechanical properties of the structure.If the number of struts is too little or too much,stress concentration will occur.The change of concrete strength grade and cable section size has little influence on the static performance of the structure.When the cable lug plate is subjected to 100% tension,the deformation is small,and there is little difference between the stress simulation analysis results and the formula calculation results.(2)The fundamental frequency of long-span cable-supported concrete structure is small,and the distribution of low order natural vibration frequency is more dense;In all vibration modes of the structure,only the cables and struts have horizontal translational movement,and the concrete floor does not show horizontal translational movement,indicating that the overall horizontal stiffness of long-span cable-supported concrete structure is large,while the vertical stiffness is small.Under the condition that other structural parameters remain unchanged,the change of thickness of floor and boundary conditions has great influence on the natural vibration characteristics of the structure.(3)Under the action of unidirectional earthquake,the joint displacement response peaks of the structure all appear at the connection point between the struts and cables in the span,and the displacement values meet the requirements of the code.When input different seismic waves,the axial force response peaks of the struts and the cable force response peaks also have small differences,both of which conform to the law of static force.Under three-way seismic action,the x-direction displacement can be ignored,indicating that the x-direction stiffness of the structure is large.Compared with the horizontal unidirectional seismic action,the displacement response values of the y-direction nodes in the main direction are the same under the three-direction seismic action,indicating that the earthquakes in the other two directions have no superposition effect on the Y-direction.When the same seismic wave is input in one direction or three directions,there is little difference between the peak values of the strut axial force and the cable axial force,indicating that the seismic action has little influence on the strut axial force and the cable axial force.(4)In the construction process of long-span cable-supported concrete structure,appropriate construction method should be selected according to the actual situation of the project and reasonable tension scheme should be developed.The stress and deflection produced by the concrete beam in the construction process are small,which meet the requirements of the code,indicating that the construction method adopted in the project is reasonable.The results of simulation analysis are same as the measured results,indicating that the analysis model established in this paper is consistent with the actual engineering,has a certain universality,and can provide technical support for similar projects.