Research On The Residual Bearing Capacity Of Concrete-filled Steel Tube Subjected To Lateral Impact

As a common load-bearing component,concrete-filled steel tube columns are widely used in important engineering structures such as high-rise buildings,long-span bridges,subways,and defense and military due to the full use of the strength and deformation advantages of two materials,steel tube and concrete.Axial compression or small eccentric compression members;during the service of the component,it will inevitably suffer some loads such as impact.Once the component is subjected to the impact load,it will cause damage or failure of the component,and even cause the structural continuous collapse.Therefore,it is necessary to evaluate the damage degree of concrete filled steel tubular components.Based on the previous research and the numerical analysis results of the finite element software ABAQUS,this paper studies the dynamic response of concrete-filled steel tubular members under the lateral impact load of the impact block,and quantitatively analyzes the impact of axial force on the impact resistance of the test piece.The damage degree of the damaged test piece was numerically analyzed.The main research work and conclusions are as follows:(1)The finite element software was used to establish the lateral impact model of the concrete-filled steel tube members and the compression model of the damaged specimen.The simulation analysis results were compared with the previous test data to verify the reliability of the material constitutive model and the modeling method.Precision.(2)The impact of pre-loaded axial force on the impact resistance of concrete-filled steel tube specimens is analyzed.A model of component impact under continuous axial compression ratio is established.Quantitative analysis shows that the axial compression ratio n = 0.7 is the critical value of lateral impact resistance of the component.When the axial pressure is less than 0.7,the axial force can improve the impact resistance of concrete filled steel tube.When the axial pressure ratio is greater than 0.7,the axial force can weaken the impact resistance of concrete filled steel tube.(3)Based on the actual working conditions,the impact model of the rigid block impacting the concrete-filled steel tube bridge pier is established,and the compression simulation analysis of the damaged specimen is performed.The main analysis is the impact mass,impact velocity,and steel tube wall thickness,Steel strength and slenderness ratio affect the lateral impact resistance of concretefilled steel tube,which provides a reference for actual engineering.