Numerical Analysis Of Axial Compressive Behavior Of Damaged RC Column Reinforced With GFRP And Steel Fiber Mortar

With the progress of building reconstruction project,a large number of columns often appear problems such as structural damage and insufficient bearing capacity.Glass fiber reinforced plastic is widely used in practical engineering because of its light weight,high strength,corrosion resistance and low price.At the same time,steel fiber cement mortar will significantly improve the mechanical properties of components as a repair material due to its reinforcement,crack resistance and good toughness.In order to achieve better reinforcement effect,a new combination of GFRP and steel fiber mortar is proposed to strengthen damaged RC columns.The main research contents and conclusions are as follows:(1)According to the existing test content,finite element models of damaged RC columns reinforced with GFRP pipes and steel fiber mortar and GFRP strips and steel fiber mortar were established by applying ABAQUS finite element software,respectively.The results are compared with the test results.The load-displacement curve,failure morphology and stress cloud of each component are analyzed to verify the correctness of the model.(2)Based on the experiment of GFRP pipe and steel fiber mortar strengthening damaged RC columns,extended analysis of parameters such as the fiber winding angle of the GFRP pipe,the strength of the steel fiber mortar and the loading method of the section are obtained.The axial compression load capacity of the combined structure increases with the angle between the fiber winding angle of the GFRP pipe and the 45° winding direction.As the strength of the steel fiber mortar increases,the axial compression load capacity increases.The section loading mode has little effect on the bearing capacity.(3)Based on the test of RC Columns strengthened with GFRP strips and steel fiber mortar,the factors such as the spacing and layers of GFRP strips and the strength of steel fiber mortar are analyzed.As the spacing of the GFRP strips decreases and the number of layers increases,the restraint on the core increases and the peak load of the combined structure increases as well as the ductility.As the strength of the steel fiber mortar increases,the peak load increases,but the magnitude of the increase decreases.With the increase of the strength of steel fiber mortar,the ductility becomes worse and the brittle failure characteristics become more obvious.(4)On the basis of numerical simulation research,limit equilibrium method and superposition method are used to modify the calculation formula of bearing capacity of damaged RC Columns strengthened with GFRP pipe and steel fiber mortar.It is found that the superposition method is in good agreement.At the same time,the superposition method are used to modify the calculation formula of bearing capacity of damaged RC Columns strengthened with GFRP strips and steel fiber mortar.The calculated value is consistent with the experimental value.