Study On Axial Compression And Bending Performance Of Corrugated Steel Tube-Concrete-Steel Tube Members

At present,domestic and foreign scholars have relatively little research on the restraint performance of corrugated steel pipes.Among them,the research direction of the mechanical properties of corrugated steel pipe-concrete-steel pipe composite members is lacking.Has not yet formed a mature and unified system.Therefore,the article observes the failure mode of the corrugated steel tube-concrete-steel tube component and analyzes the working mechanism,and studies the axial compression and pure bending mechanical properties of the component with different diameterthickNess ratios,concrete strength grades,reinforcement ratios and hollow ratios.Impact.The main work completed and the research results obtained are as follows:(1)The influence of factors such as the hollow ratio,diameter-thickNess ratio and concrete strength grade of corrugated steel pipe on the axial compression performance of the test piece is discussed.In addition,the specimens of which the steel pipe form is the ordinary steel pipe are the comparison group.The test process and the final failure form of the 14 axial compression specimens are described.The curve,load ratiotransverse deformation coefficient curve,peak load,axial bearing capacity,axial compression stiffness and ductility coefficient were compared and analyzed.The experimental study found that the external corrugated steel tube can provide a strong restraining effect for the internal core concrete,and there is no obvious damage to the component during the test loading process.In particular,specimens with small hollowness and relatively small inner diameter and thickNess did not show a significant drop after stiffness degradation,which shows that corrugated steel pipes have better displacement ductility.(2)Reasonable suggestions were proposed for the design of corrugated steel pipes applied to purely bent members.Eight pure bending specimens,including two ordinary steel pipe specimens and six corrugated steel pipe specimens,were analyzed,and the bending stiffness and bending moment-deflection curves of the specimens were analyzed.And the effect of concrete strength level on the pure bending mechanical properties of the specimen.The test results show that the internal core concrete is greatly restrained by the external corrugated steel pipe,and there is no obvious damage to the component during the loading process of the test.This is because the special wrinkle of the corrugated steel pipe makes it have good adhesion with the concrete KNot effect.The load-deflection curve of the specimen with a small hollowness and a relatively small inner diameter and thickNess after the stiffness degradation did not show a significant drop.The solid-corrugated steel pipe-concrete-steel pipe purely bent members did not appear until the load-deflection curve of the crack in the tensile zone The descending section shows that the corrugated steel pipe has better corner ductility.(3)The finite element numerical simulation method of corrugated steel tubeconcrete-steel tube components is analyzed,and the relevant performance of the axial compression and pure bending specimens proposed in this paper is theoretically analyzed with the help of ABAQUS finite element analysis software,and the curves calculated by simulation Compared with the test curve,it is found that the degree of agreement between the two is relatively high,which further verifies the reliability of the model;the main purpose of simulation is to verify the test,the verification results of the model are basically consistent with the test.(4)The results obtained from the calculation formulas of axial compression and pure bending bearing capacity of corrugated steel pipe-concrete-steel pipe members proposed in this paper are in good agreement with the test values and can accurately predict the bearing capacity of the test piece.The paper has 54 figures,15 tables and 106 references.