Finite Element Analysis On Seismic Performance Of Repaired And Strengthened Seismic-damaged Steel Reinforced Concrete Frame Columns

As an important bearing member,steel reinforced concrete(SRC)frame columns is more and more appear in the place that demand high seismic fortification,and followed by different degree of earthquake damage.Considering the factors such as financial and material,it’s not allowed to push them all down and rebuild.only take appropriate technology to reinforce reinforcing is possible.Quasi static test is an effective method to study the seismic performance of strengthened SRC frame columns with earthquake damage.However,due to the cost of the trial,it’s not feasible to carry out much quasi static test of strengthened SRC frame column with seismic damage.So appropriate finite element method is adopted to analysis the seismic performance of strengthened members.Based on the tests of the seismic performance of earthquake damaged SRC frame columns which reinforced with Carbon Fiber Reinforced Polymer(CFRP)and steel that completed,established reasonable finite element analysis models,analyzed the affecting factors of the seismic performance of earthquake damaged SRC frame columns that reinforced by CFRP and steel,carried on the theoretical derivation of the capacity of strengthened SRC frame columns.In this paper,the research content and conclusions are as follows:1.Put forward a numerical modeling method to reflect the damage degree of components,that by material performance reduction after analyzed and summarized the method and theories of earthquake damage modeling,established the relationship between the degree of earthquake damage and the material reduction coefficient.Established the numerical models by finite element software ABAQUS,and then studied the seismic performance of the strengthened columns with different degree of damage.The rationality of the damage modeling method proposed in this paper is verified when compared the simulation results with the experimental results,.2.The seismic performance of numerical model with different axial compression ratio,reinforcement of the number of carbon fiber sheet,height of carbon fiber reinforced concrete and the degree of earthquake damage are analyzed in this paper.The results show that the increase of axial compression ratio reduces the ultimate displacement of the reinforcement column and has little effect on the bearing capacity.The increase of number of carbon fiber reinforcement layers and the height of reinforcement can improve the bearing capacity and ultimate displacement of the reinforcement column.When the component damage to a certain extent,the load capacity are not restored.3.Analyzed the influence of different axial compression ratio on the seismic behavior of reinforced columns,such as reinforced steel height,angle steel thickness,plate thickness and axial compression ratio.The results show that the axial compression ratio mainly affects the ductility of the reinforcement column.The reinforcement height and angle steel thickness of the clad steel have a significant effect on the seismic performance of the reinforced column.The effect of the reinforcing plate on the seismic performance of the reinforcement columns is not obvious.4.Based on the theory of "truss-arch" model,the theoretical calculation formula of shear capacity of reinforced concrete columns with carbon fiber reinforced concrete is deduced.The calculated results are in good agreement with the experimental results,indicating that the formula is feasible.