NUMERICAL INVESTIGATION ON THE BEHAVIOR OF CIRCULAR SLENDER CONCRETE COLUMNS REINFORCED WITH GFRP BARS UNDER ECCENTRIC LOADING

Abstract

Fiber-reinforced polymer (FRP) bars have become a popular replacement for steel reinforcement in concrete buildings due to their superior corrosion resistance, magnetic non-conductivity, and better strength-to-weight ratio. The FRP material has different mechanical and chemical characteristics compared to conventional steel, which can change the performance of reinforced concrete (RC) elements when the reinforcing steel bar is replaced with FRP. The present study numerically investigated the behavior of a circular slender concrete column reinforced with GFRP bars under eccentric loading using nonlinear finite element software ABAQUS version 6.14. The experimental result presented in the literature is used to validate the FE analysis using the ABAQUS software program. The column is modeled as a circular slender column. A total of 24 specimens are modeled, with a dimension of 200mm diameter of the column with a column span length of 3000mm. The various parameters in the study are the effect of eccentricity to diameter ratio, the effect of spacing transverse reinforcement, the effect of high compressive concrete strength, the effect of the slenderness ratio, and the effectiveness of replacing steel with GFRP. All columns are subjected to different values of eccentricity to diameter ratio (0,0.2D and 0.4D). The finite element results of eccentricity to diameter ratio reduced the peak load resistance of slender circular columns from 67.86% and 85.09% compared to reference columns. The ductility of the slender columns also decreased, from 7.82% and 10.00%. Increasing the spacing of transverse reinforcement from 50mm to 150 mm reduced the peak load resistance from 1.74% to 0.52%. The ductility of a slender column is reduced from 13.04% to 9.17%. The ductility of the column increased as the spacing of the stirrup decreased. Increasing the slenderness ratio 20 to 80 decreased peak load resistance from 19.02 to 58.444%, and the ductility of a slender circular column decreased from 4.14% to 12.42%. The concrete compressive strength increased from 50 to 60 mpa, increasing peak load resistance from 12.79% to 24.63%, and the ductility of a slender circular column decreased from 12.71% to 20.76%. The Effectiveness of replacing steel with GFRP decreased peak load resistance from 34.41% to 22.13%, and the ductility of slender circular columns increased from 17.79% to 24.15%.