Behavior And Ductility Of Reinforced Concrete Columns Confined With Stirrups

Domestic and foreign scholars to study confinement properties of reinforced concrete(RC) columns has been for centuries, since the use of Confined by Hoops concrete in triaxial compression state, thereby improving compression original concrete columns own features to improve compressive strength and ductility characteristics member is widely used and studied.There are many types of common constraints,different constraints on the concrete form of constraint effects are different, but Confined by Hoops is the most common and most widely used.Confined by Hoops can improve the strength and ductility of the column so as to improve the seismic performance of the structure, improve the structure of the overall security while reducing the column cross-sectional area can be improved building aesthetics.Therefore,how to enhance and improve the lower stirrups confined concrete(RC) column strength and deformation characteristics research has important theoretical and practical value,has been the focus of scholars countries.The main contents are as follows:By collecting a large number of domestic and foreign literature constraint member axial compressive load data, filter out the impact of Confined by Hoops concrete constraints performance factors analyzed 32 sets of experimental data were noted hoops yield strength, concrete compressive strength, volume distribution hoop ratio and stirrup types on constraining performance.Chinese scholars on stirrup type affects performance constraints of concrete research less paper also consider the impact of the four factors,the stirrup λ and effective geometric constraint factor ke cited analysis Confined by Hoops performance, and because the geometric foreign scholars proposed confining factor too complicated, this paper was carried out in order to simplify and more widely used.In this paper, ABAQUS software for typical specimen for analysis, select the load reaches the yield point, the peak point and the peak point three typical time for the development of stress state of concrete and stirrups were analyzed.Establish a finite element model of a typical member of the influence Restraints effect parameters were obtained by analyzing all major parameters on Stirrups effect.According to 156 groups of test data collected literature, this paper presents recommendations confining factor computing equation.According to the newly proposed confining factor α, re-fitting the confined concrete stress-strain constitutive model feature point and a falling section slope equations presented in this article stress-strain constitutive equation is recommended. Verify the accuracy of equations by test data and ABAQUS.According to the proposed constitutive equations Xtract software, set up a 48 column section curvature ductility models, pointing out the article recommended confining factor α and axial compression ratio for Confined by Hoops reinforced concrete(RC) columns sectional curvature the impact of proposals equation μφcurvature ductility coefficient.