The Unified Equation Of Stress-strain Curve For Confined Concrete Confined

With the development of social economy,the strength of concrete and steel bars in engineering applications has been continuously improved,and the form of stirrups has become increasingly diverse.Most of the existing constitutive models of constrained concrete are based on their respective test data.Most of the models are only relatively good with their own test data,and there are not many constitutive models that can really cover and conform to most test results.This paper collects a large amount of data on the axial compression test of confined concrete,covering a range of: concrete strength is 19MPa?160MPa,volume coupling rate is 0.15%?16.7%,stirrup yield strength is 164MPa?1386MPa,longitudinal reinforcement ratio is 0? 5.87%.In this study,a database was established to analyze the influence of eight key parameters on the mechanical performance of confined concrete columns.On the basis of the database,the unified equation of the compressive stress-strain relationship curve of the constrained concrete,the calculation formula of the peak compressive strain and peak compressive stress,and the accuracy of the model in this paper are verified to provide the basis for the theoretical calculation and numerical analysis of the structure.The main research contents of this article are as follows:?1?Study the effect of concrete strength,stirrup yield strength,volume stirrup ratio,stirrup form and other factors on the strength enhancement coefficient (K_c=f_cc/f_c) and deformation enhancement coefficient (K_?=?_cc/?)c) of confined concrete reinforced column.Through comparative analysis,this study found that for rectangular columns,considering the convenience of construction and the effect of restraint,it is better to use the mesh format of stirrups.?2?The constitutive relational database of confined concrete was established and the test data of the database were uniformly processed.By analyzing the test data in the database,the unified equation of stress-strain curve in confined concrete compression is proposed.Compared with the existing models,the unified equation is in good agreement with the experimental data.?3?In this study,formulas for calculating peak compressive stress and peak compressive strain of confined concrete are proposed.Compared with the existing formulas of peak compressive stress and peak compressive strain,the proposed formula has a better prediction effect.