| China is vigorously promoting the process of urban renewal.Assembled reinforced concrete columns are an important part of assembled concrete structures.During the design reference period,they are prone to degradation of mechanical properties and deformation properties,affecting the normal use of the structure.The reconstruction and reinforcement methods of traditional structures do not meet the requirements of green sustainable development.Carbon fiber reinforced polymer(CFRP)is widely used in the reconstruction and reinforcement of concrete structures because of its high strength,light weight,simple construction,good durability and excellent fatigue resistance.Therefore,in order to study the mechanical properties of assembled concrete columns and the restraint effect of CFRP sheets on assembled concrete columns,this paper uses ABAQUS finite element analysis software to analyze the damage of assembled concrete columns,the arrangement of CFRP sheets and the strength grade of materials.The main research contents and results are as follows:1.Based on the experimental study on the compressive performance of prefabricated concrete columns confined by CFRP sheets,the ABAQUS software was used to analyze how to simulate the test in detail in the selection of models and elements,the determination of material properties and constitutive relations,the establishment and solution of models,and the interaction between materials.The finite element analysis model of the column was established by using the concrete plastic damage model.Based on the results of the finite element model and the relevant experimental data,this paper compares and analyzes the failure mode,ultimate bearing capacity and load-displacement curve of the components.The results show that the simulation results are in good agreement with the experimental results,which verifies the accuracy of the finite element model.2.The influence of the number of CFRP layers on the compressive performance of assembled concrete columns was studied.The results show that with the increase of the number of CFRP layers,the ultimate bearing capacity of the large and small eccentric compression specimens will not increase linearly with the increase of the number of layers,and the relative increase rate will gradually decrease.Combined with the analysis of simulation results,there is an optimal number of bonding layers,it is recommended to use 2-3 layers as the ideal bonding layer of CFRP laminate.3.The influence of CFRP strip width and net spacing on the compressive performance of assembled concrete columns is analyzed.The results show that the ultimate bearing capacity of assembled columns increases with the decrease of net spacing when the strip width is the same.When the net spacing is the same,as the width of the strip decreases,the number of cracks in the component is large and the width is small,and the ultimate bearing capacity of the assembly column gradually decreases.4.The influence of concrete strength grade on the compression performance of CFRPconfined assembled concrete columns was investigated.The results show that when the core concrete strength grade is constant,the ultimate bearing capacity of the specimen increases with the increase of the precast concrete strength grade.When the concrete strength grade of precast formwork is constant,the ultimate bearing capacity of specimens increases with the increase of core concrete strength grade.Compared with the increase of precast formwork concrete grade,the increase of core concrete strength grade has more obvious effect on the ultimate bearing capacity of specimens.5.The influence of CFRP sheet reinforcement on the compression performance of assembled concrete columns with different damage degrees was studied.The results show that when the damage degree of the component is light,the ultimate bearing capacity of the assembled column is greatly improved by CFRP sheet reinforcement.The heavier the damage degree is,the smaller the ultimate bearing capacity is,but the ductility is improved to some extent. |
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