Study On Eccentric Compression Performance Of L-shaped Composite Column Of Modular Wall Light Steel Concrete Frame Structure

With the national industrial adjustment and the advocacy of green concept,prefabricated buildings have become the mainstream development direction of the construction industry and the main way for future buildings to move towards intelligent construction.In view of the new needs of the development of the industry,this paper proposes a new type of prefabricated building structure system-module wall light steel concrete frame structure system.In the project,it can minimize the problems of too scattered construction site components,complex connection methods,low assembly efficiency,complicated component management,and many construction processes,which reduces the construction difficulty and project cost.As the main bearing member of the system,the mechanical properties of light steel concrete composite columns are still unclear.In this paper,the L-shaped corner column in the system is taken as the research object.In the project,the corner column is in the eccentric compression state because the engineering axis and the neutral axis are not parallel.Therefore,in order to fully understand the compression performance of the composite column,the experimental study and theoretical analysis of the eccentric compression performance of the L-shaped composite column of the modular wall light steel concrete frame structure are carried out.The main research contents and conclusions are as follows:(1)Considering slenderness ratio,eccentricity,loading angle and steel thickness parameters,nine L-shaped light steel concrete composite column specimens were designed.The failure characteristics,load-axial displacement curve,load-column deflection curve,lateral deformation of column body and strain development of steel and concrete of each specimen were obtained by eccentric compression test.The test results show that the L-shaped composite column of the modular wall light steel concrete frame structure has experienced the elastic stage,the elastic-plastic stage and the descending stage under the eccentric compression load,and the specimen is finally dominated by the concrete crushing failure in the compression zone.The bearing capacity is greatly affected by the eccentricity.When the eccentricity increases from 30 mm to 120 mm,the bearing capacity is reduced by 47%.The concrete strain of the middle section of the specimen column conforms to the plane section assumption,and the concrete and steel work well together.(2)Based on the experimental conditions,ABAQUS finite element software is used for numerical simulation analysis.The finite element simulation results are compared with the experimental results to verify the accuracy of the finite element model.Based on this,the variable parameter analysis of the composite column is carried out.The single factor analysis results show that the influence of each parameter on the eccentric bearing capacity of the composite column is eccentricity > slenderness ratio > steel thickness > loading angle.With the increase of slenderness ratio,the ultimate bearing capacity decreases rapidly,and the initial stiffness decreases with the increase of slenderness ratio.Steel strength,concrete strength and steel thickness can improve the ultimate bearing capacity of the specimen,but have little effect on the initial stiffness.The reinforcement can be configured as a structure.(3)According to the test and a large number of finite element simulation results,combined with the unified strength theory regression analysis,the calculation formula of the eccentric compression bearing capacity of the L-shaped composite column of the modular wall light steel concrete frame structure is obtained.Compared with the test results and the finite element simulation results,the two are less discrete and the formula is more reliable.It can be used for the design of composite columns.