Study On Axial Bearing Capacity Of Column Strengthened With Hoop Prestressed Steel Wire

The reinforcement of the hoop prestressed steel strand can effectively improve the bearing capacity of the concrete column,and greatly improve its deformation performance.Through actively constraining concrete,it is a reinforcement method with good application prospect to improve the compressive strength,and to a certain extent block the axial cracks in the compression concrete.Most of the existing research results are based on the small size circular column and square column,but the study of the interrelationship between the size of the component and the shape of the section and the reinforcement effect is quite limited.This paper focuses on the research of the axial bearing capacity and failure mode of the reinforced prestressed steel wire.Through the axial compression test of three different size column structures under the same lateral binding force,the relationship between the component size and the reinforcement effect of the column structure is discussed,and the different length and width ratio moments are carried out.In the axial compression test of column structure reinforcement,the influence of the length width ratio on the reinforcement effect of the reinforced column is explored.Finally,based on the Mander theory,the calculation formula of core concrete and the calculation formula for the axial bearing capacity of the reinforced column for the circumferential prestressed steel stranded wire mesh are put forward.The main research results of this paper are as follows:(1)The results of size effect study show that under the same lateral binding force,the strength and strain ratios of small,medium size and large size concrete square columns are almost equal.It shows that the size of the member has little influence on the reinforcement effect,and the stress of the main reinforcement,the strain of concrete,the strain of the stirrup and the strain of the stirrup are also analyzed.The relationship between strain and axial force of steel strand is discussed.It is proved that the strength enhancement mechanism of reinforced concrete columns strengthened with ring prestressed steel strand is the enhancement of core concrete strength.(2)Experimental study on the shape effect of a reinforced column reinforced by a prestressed steel stranded wire.The effect of length and width ratio on the reinforcement effect of reinforced concrete columns was studied by axial compression test of 4 groups of 16 specimens.The results show that the circumferential prestressed steel wire mesh of concrete columns with rectangular section also has significant restraining effect,largely enhancing the cracking load of components and the effective restraint of the development of the cracks.In addition,it is found that the higher the increase of the ratio of length to width,the lower bearing capacity of strengthened members.(3)The results of the nonlinear finite element analysis of the whole process show that the results of the numerical analysis are basically consistent with the test results on the failure mode,the axial bearing capacity and the stress-strain curve.The reinforcement effect of the circumferential prestressed steel wire mesh is obtained by the analysis of the parameters.It is also verified that under the same lateral restraint,the size of the member has little effect on the reinforcement effect of the strengthened column.(4)On this basis,a formula for calculating axial compression bearing capacity of HPSW strengthened columns is put forward,and the difference between them is less than 5%.