Numerical Analysis Of Axial Compression Performance Of Damaged Column Reinforced With Steel Mesh And Steel Fiber Cement Mortar

In recent years,structural reinforcement technology has become one of the research hotspots in the field of civil engineering.Reinforcement method of steel mesh mortar is a kind of surface reinforcement technology,which has the advantages of small section increase,mature construction,low cost,good heat resistance,good combination of old and new interface,and wide application.Adding steel fiber to mortar can improve its crack resistance,ductility and durability.However,the existing research mainly focuses on the reinforcement of undamaged components,while in actual engineering,many components that need reinforcement often have damage.Therefore,the axial compressive properties of reinforced concrete columns reinforced by steel fiber cement mortar with steel mesh are studied in this paper.Based on the axial compression tests of seven damaged reinforced columns,the effects of the damage degree,the spacing of steel mesh and the discretencies of reinforcement method on the mechanical properties of the reinforced columns were studied.Due to the tedious production of specimens,the test will be affected by practical factors.Therefore,the numerical model of the reinforced column was established by using the finite element software ABAQUS on the basis of the test.The load-bearing capacity,load-displacement curve and stress-strain nephogram of each component of the reinforced column were obtained,and compared with the test data and the failure pattern of the specimen,it was found that the simulation was in good agreement with the test,which verified the rationality of the numerical model established in this paper.The influence of the thickness and strength of steel fiber cement mortar,the diameter,strength and spacing of transverse and longitudinal reinforcing bars in the reinforcement layer on the axial compressive properties of the reinforced column was studied.The results show that the bearing capacity of the strengthened column decreases with the increase of damage degree.The thickness and strength of steel fiber cement mortar increase linearly on the bearing capacity of reinforced column.The transverse diameter of steel mesh has a great effect on increasing the bearing capacity and improving the ductility of the reinforced column,while the transverse strength has a certain effect on the ductility of the strengthened column,and the transverse spacing has a great effect on the bearing capacity and ductility of the strengthened column in a certain range.The increase of the longitudinal diameter of the steel mesh has a certain increase in the bearing capacity of the strengthened column,but the increase is far less than that of the transverse diameter of the steel mesh.The strength and spacing of the longitudinal reinforcing bars have little effect on the bearing capacity and ductility of the reinforced column.Based on the experimental and simulated data,a formula for calculating the axial bearing capacity of damaged concrete columns reinforced by steel fiber cement mortar with steel mesh is put forward,which takes into account the damage of inner column and the restraint effect of reinforcing layer.