The Study On Mechanical Properties Of Concrete Filled Steel Tubular Member With Separation

As a new type of combination structure,concrete filled steel tube structure is widely used in civil engineering,especially in the high-level structure and large span structure.However,the separation problem in concrete filled steel tubular structure is a common quality problem in construction site.It affects the interaction between steel tube and core concrete,leads to the weaken of mechanical properties.Therefore,it is significance to study the influence of separation in concrete filled steel tubu member.In this paper,the mechanical properties of separation in concrete filled steel tubu member are studied.The work done in this paper is as follows:(1)Based on the research status of concrete filled steel tubular members with voids,the separation classification,causes and precautionary approach are summarized.The ABAQUS software was used to establish the model of separation in concrete filled steel tubu member.The results of finite element simulation results and related test were compared and analyzed.It verified the accuracy of the model.(2)The bending,axial compression and compression-bending models of concrete filled steel tubu members were established by ABAQUS.The stress nephogram,load-displacement curve,skeleton curve,stiffness degradation curve,strength degradation curve and cumulative energy dissipation curve were obtained.The effects of separation ratio,concrete strength,steel tube strength,steel tubular thickness and axial compression ratio on the mechanical properties of the three components are studied.The working process and failure characteristic of the concrete filled steel tubu member were analyzed.Suggestion for application in engineering practice are put forward.(3)According to the results of finite element simulation,the multi-linear regression of simulation data is carried out by MATLAB software,and it put forward the revised formula of bearing capacity of the axially compressed members of separation in concrete filled steel tube,considering the influence of void ratio,concrete strength,steel tube strength and steel tubular thickness.