Experimental Research On Axial Compression Performance Of Steel-Wood Composite Column

Wood has the advantages of environmental protection,natural beauty,high degree of assembly,and recyclability.Especially when the felling and utilization of wood reach a certain balance,the advantages of wood utilization are more obvious.As a high-efficiency building material,steel has the advantages of high strength,plasticity,and good ductility.This article starts from exploring the advantages of combining steel and wood materials,using steel as the main load-bearing component,and wood forms a certain buckling constraint around the steel,and strives to give full play to the advantages of steel and wood materials,and develop and promote environmentally friendly and beautiful prefabricated composite column components.Proposed two combined cross-section forms,one is cross steel column,wood combination,bolted between steel and wood;the other is cross steel column with flange,wood combination,there is no bolt between steel and wood.Aiming at the two proposed steel-wood composite column forms,the axial compression test research,finite element analysis and theoretical calculation formula derivation are carried out,and the axial compression performance of the steel-wood composite column is studied.The main research contents are as follows:（1）Twelve steel-wood composite column specimens were designed and manufactured,and the axial compression performance test was carried out.The influence of bolt spacing,thickness of cross-shaped steel column,whether to add flanges,and slenderness ratio on the axial compression performance are analyzed.The test results show that when the specimen reaches about 50% of the ultimate load,the surrounding wood has a certain restraint effect on the flange of the cross steel column.When the ultimate load is reached,the steel column yields,large out-of-plane deformation occurs,and the wood is compressed at the same time.The timber was damaged by the axial load and the squeeze of the steel column flange,and the specimen eventually lost the bearing capacity.（3mm and 5mm specimen constraints）The axial load bearing capacity of the specimen increases with the increase of the thickness of the steel plate;the bolt spacing decreases,the initial stiffness of the specimen increases,and the bearing capacity is less affected;the initial stiffness and bearing capacity of the combined column with external flanges decrease with the increase of the slenderness ratio.（2）The finite element model of the composite column was established using ABAQUS software,and the UMAT subroutine of the wood constitutive model was compiled,and the model was verified based on the material test and specimen test data.The stress state and failure mode of the two combined column types: bolt connection or external flange are analyzed and the model is in good agreement with the test.（3）The theoretical calculation formula for the axial compression bearing capacity of the steel-wood composite column was established.The axial compressive bearing capacity of the cross-shaped steel-wood composite column is proposed.The slenderness ratio correction factor of the composite column,the timber compressive bearing capacity correction factor and the bolt spacing influence factor are proposed.The error between the calculated value and the experimental data is about 10%,which is in good agreement.The theoretical calculation formula can provide a reference for the follow-up research and engineering application of the steel-wood composite structure.