Sutdy On Axial Compression Performance Of Aluminum-timber Composite Column

With the rapid development of national economy,the notion of energy-saving,environmental protection and sustainability has been widely concerned in our country,and the constructions are built in a resource-saving and more convenient way with lighter weight.However,the existing problems of heavy building materials,high transportation cost and serious waste of resources are still severe,by reason of which a new kind of aluminum alloy-wood composite columns is designed in this thesis.Aluminum alloy-wood composite columns are extensively used in coastal cities,for they have strong corrosion resistance,and their structural weight can be reduced to a great extent under sufficient load-carrying capacity,with the structure dynamic response under wind load or earthquake load is alleviated.Therefore,it is of great potential and significance to have a deeper research on mechanical behavior of the aluminum alloy-wood composite columns.In view of the mechanical behavior of this composite column,the main contents and conclusions of this paper are as follows:（1）20 aluminum alloy-wood composite columns,pure aluminum pipes and pure wood columns with different parameters were designed and produced.Through the axial compression tests on all the specimens,it is concluded that with the increase in the wood infill’s size and the thickness of the aluminum pipes,the buckling failure location of the composite column gradually changes from the end of the it to the middle of the it.The load-displacement curve of aluminum alloy-wood composite columns includes elastic stage,elastic-plastic stage,buckling stage,failure stage and secondary rising stage.Thickening aluminum pipes and sticking CFRP cloth on the specimen will enhance the restraint on the wood infill,which reduces the load drop in the buckling stage.The circumferential deformation of composite columns can also be effectively restrained by sticking CFRP cloth on specimen.（2）Initial stiffness,and ductility of composite columns are greatly improved compared with pure aluminum pipes and pure wood columns.By analyzing the influence of the wood infill’s size,the thickness of the aluminum pipe,the position and layers of the CFRP cloth on the axial compression performance of the composite columns,it is found that the aluminum pipe’s thickness has the most obvious effect on bearing capacity,initial stiffness and structural efficiency,and the wood’s size has the most obvious effect on ductility.Whether there is cement paste between the aluminum pipe and the wood infill also greatly affects the axial compression performance of the composite columns.（3）The calculation formula of bearing capacity of aluminum alloy-wood composite columns is proposed by substituting the stability coefficient specified in relevant codes into the superposition theory,and it can be concluded that the deviation between the calculated value and the test value is mainly caused by the cross-sectional area and strength of the cement paste in the composite columns.The formula of the cement paste reduction coefficient₍（8） is therefore obtained by fitting and is substituted into the superposition theory.Finally,the applicability and accuracy of the proposed formula for calculating the bearing capacity are verified by analyzing the data from the composite columns under all working conditions.In this thesis,the bearing capacity mechanism and axial compression performance of aluminum alloy-wood composite columns are studied by axial compression tests,and the formula of bearing capacity is given,which provides the experimental reference and theoretical basis for popularizing aluminum alloy-wood composite columns in the future.