Study On Mechanical Properties Of Hollow Square Steel Composite Columns Embedded Steel Fiber Ceramsite Concrete.

With the construction industry development,and the construction technology level continuous improvement,the research most on the concrete filled steel tube composite members by civil industry researchers focus on the concrete filled steel tube structure.However,the researches on Concrete Filled Double Skin Tubes,referred to as CFDST was a few.Although the technology of ordinary concrete filled steel tubular members and concrete filled steel tubular members is more mature and the construction method is common,but the bearing capacity,toughness,fire resistance and other characteristics are not as good as CFDST.At the same time,CFDST structure has obvious advantages of section development,bending section stiffness,light weight and good seismic performance.In response to the call of green building materials,the ceramsite and steel fiber in Steel Fiber Reinforced Ceramisite Concrete,referred to as SFRLC,which can improve the corresponding mechanical properties of concrete.CFDST structure also includes steel fiber ceramsite concrete hollow steel columns.The mechanical properties of hollow steel blocks are studied in this thesis.The steel fibers were embedded in the steel fiber of ceramsite concrete and combined with finite element simulation to study its mechanical properties.The theoretical basis of the application of steel fiber ceramsite concrete block hollow steel column in practical engineering.The main work of this thesis includes:(1).Nine hollow square steel composite columns with embedded steel fiber ceramsite concrete and one solid steel fiber ceramsite concrete column with the same outer steel pipe size were subjected to monotone static loading test by changing the substitution rate,hollow rate and eccentricity of ceramsite concrete,and through the test,the thesis obtain the specimens failure modes.This thesis analyzed the load-displacement curves and load-strain curves of the measured points,the researched influence of the replacement ratio,hollowing ratio and eccentricity in the mechanical properties of specimens.The failure modes of the axial compression specimens present flaw in the sheath and failure in waist Thumb compression.The concrete on the side of compression was crushed from the eccentric compression specimen,Concrete of the tension side had cracks.(2).Based on the ABAQUS finite element software,the entire column loading process composed of ceramsite square steel with fiber of steel has been analyzed with reasonable material constitutive ratio.The failure modes of the finite Element model,the stress nephogram,the load displacement curve and the final bearing capacity were obtained.The results show that: specimen failure mode,load displacement curve was BOM according to experimental results.Rationality of the final element model was proved.(3).Using the numerical analysis method for the composite column of ceramsite steel fiber.The calculation formula of the axial load capacity and bias suitable for this composite column type is analyzed.This thesis checked the test and calculation results.Results show that: the calculated accuracy of the results meets the requirements,therefore,it may provide reference in engineering for calculating the bearing capacity of similar components.