Experiment And Analysis On Eccentric Compression Performance Of Shaped Steel Reactive Powder Concrete Column

Nowadays,many buildings have higher and higher requirements for structural performance,and the steel reactive powder concrete structure has begun to enter the field of view of scholars at home and abroad.As a new type of composite structure,it is suitable for large-span and super high-rise buildings.Compared with the ordinary reinforced concrete structure,the steel reactive powder concrete composite structure has the advantages of ultra-high strength,high durability,good seismic performance,etc.,and can be applied to the freezing and thawing environment.Compared with the steel structure,the steel reactive powder concrete composite structure makes up for the shortcoming of the steel structure’s poor fire resistance.However,the research and design method of eccentric compression test of shaped steel reactive powder concrete columns at home and abroad are not yet mature,so the research on such composite structures has broad prospects.In this paper,a total of 6 shaped steel reactive powder concrete columns were designed and fabricated,and static loading tests were carried out on them.The crack characteristics,failure modes,load-vertical displacement curves,and load-deflection curves of the eccentrically compressed shaped steel reactive powder concrete columns were analyzed.,The lateral deflection of 6 columns was analyzed,and the 6 columns were divided into 4 different reference groups,and the eccentricity,steel distribution ratio,slenderness ratio,and longitudinal reinforcement ratio were compared to the eccentricity of the steel reactive powder concrete column.Influence of compressive bearing capacity.On the basis of the test,the nonlinear analysis of the six columns was carried out with finite element simulation software,and the results were compared with the test data.Finally,based on the research of scholars at home and abroad,the formula of the eccentric distance increase coefficient is deduced,and the calculation model of the eccentric compression normal section bearing capacity of the section steel reactive powder concrete column is established according to the difference of the neutral axis position,and the normal section bearing capacity is proposed.Force calculation formula.The results of the study are as follows:（1）The cracks of the six columns are basically symmetrically distributed,and there will be an obvious main crack on the tension side when they fail.The final failure of the 6 columns manifested as concrete crushing in the compression zone.Except that the load-deflection curves of the specimens damaged by small eccentric compression will show a steep drop,the curves of the other specimens damaged by large eccentric compression are relatively gentle,showing good ductility.（2）The eccentric distance,steel distribution ratio,slenderness ratio and longitudinal reinforcement ratio have a great influence on the eccentric compressive bearing capacity of the section steel reactive powder concrete column.The peak load and flexural stiffness decrease with the increase of eccentricity,increase with the increase of steel distribution ratio,decrease with the increase of slenderness ratio,and increase with the increase of longitudinal reinforcement ratio.large and enlarged.（3）The lateral deflection of the specimen is symmetrically distributed along the column height,and basically conforms to the half-wave sine curve,and the mid-span section is always the section with the largest deflection.（4）The column section basically conforms to the assumption of plane section,but the cracking of concrete or the bond-slip between steel and concrete leads to a turning point in the strain in the compression zone of some columns,but it generally conforms to the assumption of plane section.（5）The load-deflection curve,load-strain curve and lateral deflection curve of the test column are basically consistent with the finite element simulation results,which verifies the correctness of the finite element simulation.（6）Substitute the equivalent coefficient of the tension zone and the influence coefficient of the tensile strength of the steel fiber reinforced concrete in the tension zone into the bearing capacity calculation formula.The results show that there is little difference between the calculated value and the experimental value.