SIZE EFFECT ON PERFORMANCE OF CONCRETE FILLED STEEL TUBE CIRCULAR COLUMN

Abstract

This study aims at investigating the size effect on the performance of high strength CFST columns under axial load and to create regression formula for better estimation of the capacity of the column as the parameters increases by unit. The nonlinear finite element analysis program ANSYS2020R2 is used to study the performance of the column and SPSS to create the regression formula and to identi fy the correlation behavior of the parameters with the capacity of column. A displacement controlled loading type is used. Concrete and steel damage plots and load-displacement graphs are the main out put from ANSYS2020R2 and the correlation and regression coefficients are the outputs from SPSS. The result from the finite element analysis (ANSYS2020R2) has been validated by the experimental result from literature. A parametric study is conducted using 64 circular CFST columns to investigate the load carrying ca pacities, to determine the correlation and regression coefficients. Here, the main parameters are steel grade, Diameter of the column, thickness of the steel tube and grade of concrete. The performance (axial load carrying capacity) of columns for C-50MPA increases by an average value of 11.59 % as the column size increases by 10mm Diameter of the column. For 60MPA and 70MPA grade of con crete the load capacity of the column increases by12.55% & 12.78% respectively for 10mm incre ment of diameter of the column. For small size of the column there is a 0.02% average difference b/n FEM analysis result and result from regression formula. And for large size of the column there is 8.98% difference b/n the FEM & regression formula load result. As the size of the column increas es, the accuracy of the regression formula decrease