Study On Axial Compressive Performance Of T-shaped Steel-wood Composite Columns

Under the background of double carbon,the advantages of wood structure architecture are increasingly prominent.Modern wood structure building is a new situation of green building,which has good ecological benefits in low carbon energy saving,recycling,garbage reduction,carbon sequestration and carbon storage and so on.Through the organic combination of steel structure,wooden structure is exploring more possibilities of prefabricated buildings,which plays an important role in promoting the industrialization development and green development of China’s new buildings.In this thesis,a new type of T-shaped steel-wood composite column is put forward.And it is made by connecting steel and wood with bolts.The axial compression test and finite element simulation study were carried out on all the specimens,and the load-axial displacement curve,load-lateral displacement curve and load-axial strain curve of the specimens were analyzed.Studied the effects of slenderness ratio,board thickness,and bolt spacing on the compressive ultimate bearing capacity of steel-wood composite columns.Wood has anisotropy.Through theoretical derivation and experimental study,a wood smooth grain compression stress-strain relationship is derived and applied to the finite element simulation to increase the accuracy of steel and wood composite column simulation.The conclusions are as follows:(1)The failure mode of steel column is flexural-torsional buckling,and the wood column is plastic failure,and the steel-wood composite column is flexural-torsional buckling failure.(2)The load-axial displacement curves show that with the increase of slenderness ratio,the peak load,stiffness and ductility of steel-wood composite columns are decreasing;with the increase of planks thickness,the peak load,stiffness and ductility of steel-wood composite columns are increasing;with the increase of bolt spacing,the peak load of steel-wood composite column becomes smaller and smaller,and its stiffness has no obvious change.(3)The peak load of the steel-wood composite column specimen is greater than the sum of the peak loads of the pure steel-wood column and the pure steel column specimen,which shows that the combination of steel and wood with bolts has played their respective advantages.(4)Based on the analysis of yield point and buckling strain,combined with experimental phenomena,the mechanical mechanism and composite effect of steel-wood composite columns are studied.(5)From the theoretical formula and the wood compression test based on acoustic emission,the original elastic-plastic constitutive model is added,so that the stress-strain relationship when the wood is in the direction of the grain,which is proved to be suitable for the finite element simulation of steel and wood composite columns.(6)For three pure steel columns and composite columns with different heights,the finite element simulation is approximately consistent with the failure mode and peak load of the test specimen.It can be seen that the finite element simulation is reliable.