Research Of Size Effect On Compressive And Seismic Behavior Of CFRP Reinforced Concrete Column

Fiber reinforced polymer(FRP for short)are widely used as reinforcement materials in practical engineering.Research indicates that FRP reinforcement can increase the strength and ductility of structure members and improve the compressive strength and peak strain of concrete.The mechanical condition of concrete columns reinforced with FRP cloth are different from unreinforced columns,The difference is that the unreinforced concrete columns are under uniaxial compression state,however the columns reinforced with FRP are subjected to triaxial stress.At present,the conclusions of domestic and abroad research on the mechanical properties of concrete columns reinforced with carbon fiber reinforced polymer(CFRP)are mainly based on the study results of small-sized.There are few experimental studies was conducted by large-sectional CFRP-reinforced concrete columns.In this situation,the further research of CFRP-reinforced concrete columns are of great significance.This paper analyzes the reinforcement effect of CFRP cloth on concrete columns with different cross-sectional dimensions.It is going to focus on two aspects:(1)the size effect of axial compression performance of CFRP-reinforced concrete columns under cyclic loading,(2)the size effect of seismic performance of CFRP-reinforced reinforced concrete columns.In the first experiment,a total of 30 concrete columns were divided into three groups,which included 10 members for each of them,and their side length was 200 mm,400mm,and 600 mm,respectively.The mechanical performance of reinforced concrete columns with different cross-sectional dimensions were analyzed under one directional repetitive full loading and unloading or partial loading and unloading,and numerical simulation using finite element software ABAQUS studied the impact of various parameters on its mechanical properties.The second experiment was designed to three groups including 4 reinforced concrete columns for each,whose side lengths was 150 mm,300mm,and 450 mm respectively,and the analyze for the variation rule of seismic performance in columns with different cross-sectional dimensions under pseudo-static test was also conducted.Numerical simulation using ABAQUS explored the influence of various parameters in the skeleton curve of reinforced concrete column.The main conclusions are as follows:1.Under axial load,the peak stress of plain concrete columns increases firstly and then decreases with the growth of size,and reinforced concrete columns are the same tendency.2.Under low cyclic repeated and reversed loading,the yield load of CFRP reinforced specimens with middle and large dimensions increases significantly.When the axial compression ratio is 0.3 and 0.45,The ultimate load of the the reinforced specimens increases significantly compared with the unreinforced specimens.3.The energy dissipation coefficient of the small column decreasing firstly and then increasees with the growth of the axial pressure ratio,middle column increase with the growth of the axial pressure ratio and the tendency of the large-sized columns is increasing firstly and then decreasing.4.Under the same conditions,the deformation capacity of the medium-sized column is the best,and the most remarkable increase of the ductility coefficient happens in the small-sized columns.5.In the normalized load-displacement skeleton curve,when the displacement is the same,the load of the concrete column decreases as the size of the member rising.