Research On Axial Compression Performance Of Damaged Reinforced Concrete Columns Reinforced By Steel Mesh With Steel Fiber Mortar

The reinforcement of steel mesh with mortar is a new type of reinforcement technology.This method has the advantages of less increase in the cross-section,good durability,low cost,simple process,etc.And compared with ordinary mortar,steel fiber mortar has obvious improvement in strength,toughness,crack resistance and ductility.Therefore,the reinforcement method of steel mesh with steel fiber mortar was proposed by scholars.However,the research on this method mainly focuses on the reinforcement of undamaged components.In view of the fact that the reinforcement in actual projects was often carried out when the structure was damaged.Therefore,in this paper,the axial compression performance of the damaged reinforced concrete columns reinforced by steel mesh with steel fiber mortar will be studied by combining experiment and theory.The specific work is as follows:The 8 reinforced concrete columns for different degrees of pre-demage were designed and manufactured.The destruction process and patterns of the specimen which was under the influence of the axial pressure were analyzed.Based on the test data,the load-displacement curve of the test piece was analyzed.The 8 damaged ordinary reinforced concrete columns were reinforced by the method of steel mesh with steel fiber mortar.And the destruction process and patterns of the reinforced column which was under the influence of the axial pressure were analyzed in detail.Based on the test data,the load-displacement curve,load-strain curve and axial compression bearing capacity of the reinforced column were analyzed in detail.The specimens of the third-level damage column reinforced were compared to explore the effect of adding steel fiber mortar on the axial compression performance.The specimens of the second-level damage column reinforced were compared to explore the discreteness of the reinforcement method and the influence of the horizontal and verital spacing of the reinforcement mesh on the axial compression performance.The specimens of the different damage levels column reinforced were compared to explore the effect of built-in columns with different damage levels on the axial compression performance.The reinforcement efficiency of this reinforcement method was explored by comparing and analyzing the load-displacement and axial bearing capacity of reinforced concrete columns before and after reinforcement.The test result showed that the reinforcement method of steel mesh with steel fiber mortar was an effective reinforcement method.The reinforcement method had less discreteness,which can greatly improve the ultimate bearing capacity,ductility and crack resistance of the reinforced column.Among them,reducing the transverse reinforcement spacing of the reinforcement column can effectively improve the ductility of the reinforcement column,and reducing the longitudinal reinforcement spacing of the reinforcement column can effectively improve the bearing capacity of the reinforcement column.With the increase of the damage level of the builtin column,the strength of the reinforced column increased first and then decreased.Dutility was directly proportional to damage level.When the built-in column was secongdary damage,this reinforcement method had the highest reinforcement efficiency.According to the comparison,the reinforced concrete column strengthened the average load capacity by 93.07%,and the average displacement increased by 100.7%after the reinforcement.Based on the result of the test,this paper put forward the calculation formula of the axial compression of the damaged reinforced concrete column reinforced by the steel mesh with the steel fiber mortar with referring to relevant standards and literature.The calculation result agreed well with the test,and provided reference for engineering applications.