| Concrete filled steel tube composite column is empty containers in the solid concrete filled steel tube composite column development on the basis of the formation of a new type of composite column,in addition to the high bearing capacity and seismic performance advantages,also has light weight,good extension and on cross section,the characteristics of better dynamic performance,therefore,in recent years,the concrete filled steel tube composite column is widely applied in high-speed room,bridge and tunnel with high-rise buildings;Aiming at dynamic loading,such as composite column in the impact and shock in the research,the construction technology has not been considered in the construction load and the influence of pressure,therefore,this article is based on the lateral impact of empty container shaped concrete filled steel tube composite column in the experiment,using the simulation software of ABAQUS simulation to verify the test conditions,and by considering the construction technological process of composite column,steel tube concrete initial stress are introduced to explore the construction load under the premise of existence,the composite column under the impact load are studied.The research contents of this paper include:(1)Using the guide rail type of drop hammer impact testing machine for empty containers in the shape of the concrete filled steel tube composite column transverse impact test,the test process,using force sensor,high-speed cameras recorded the impact force of impact in the whole process of component time history curve,cross displacement time history curve,embedded surface unloading time history curves of strain and axial force time history curves,considering the impact factors such as height,boundary conditions and axial compression ratio of specimen damage modal form of volatility process curve in a timely manner.The test results show that the external reinforced concrete can coordinate with the hollow octagonal steel tube and concrete-filled steel tube and work together.The fixed constraint condition improves the deformation resistance of the composite column compared with the simply supported one.The axial compression ratios of 0.1 and 0.2 had no significant impact on the specimens under impact load.(2)Established in the form of concrete filled steel tube composite column under impact load using ABAQUS finite element analysis model,the dynamic strain rate effect is taken into account,contact interface properties,meshing quality and pseudo strain energy control and other important factors,finally from the specimen failure mode,impact force time history curve and cross displacement time history curve of contrast verification,validation results show that the established finite element model can effectively simulate accurately the impact of empty container shaped concrete filled steel tube composite column under the load of mechanical properties.(3)Based on the working condition of test and simulation,the finite element analysis model of concrete filled steel tubular initial stress,with the introduction of concrete filled steel tubular initial stress load as the early stage of the construction,to explore the early stress on the dynamic response of a composite column under the impact load,formula and theory analysis and according to the rules of the steel and concrete frame and box the ultimate bearing capacity of composite column simulation values.The impact resistance of composite columns with different initial stress coefficients under different impact energies and different axial compression ratios is analyzed.The simulation results show that the initial stress of concrete-filled steel tube(CFST)under construction has a great influence on the impact stage and the impact duration of the hollow box CFST composite column,which reduces the flexural rigidity of the section of the specimen and the working performance of the contact interface of various components,and increases the mid-span lateral deformation of the specimen. |
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