ACI design code for slender reinforced concrete columns
Aw, Chin Wai
Date of Issue2009
School of Civil and Environmental Engineering
This report aims to study the behavior of slender reinforced concrete columns under eccentric compressive loads. The influences of variables such as slenderness ratio, eccentricity ratio, material strength, and steel reinforcement ratio on the failure loads of slender columns were studied. In total, 150 columns have been analyzed in this report. All specimens data used in this paper were obtained from the experiments of past researchers. Assume all the slender columns are under pinned-pinned condition. The slenderness ratio used in this paper is in a range of 29.35 to 105.56, the eccentricity ratio of 0.08 to 1.00, reinforcement percentage of 0.64% to 5.24%, specified compression strength of concrete of 16.2MPa to 97MPa, and specified yield strength of steel of 272MPa to 625MPa. The analysis results and discussion showed that the failure loads of slender columns decrease with an increase in slenderness ratio, an increase in eccentricities of load, a decrease in the concrete strength and a decrease in the reinforcement ratio. Although the results of different codes and theoretical methods would be slightly different, but the overall trends of the predictions are reasonable and acceptable. The analysis method based on ACI 318 is the main focus of this paper. However, different analysis methods based on selected codes: BS 8110 and EC 2; theoretical methods: transformation method and P-delta method are also studied. The experimental failure loads were compared with the predicted failure loads. Generally, ACI 318 gives the most conservative predictions whereas EC 2 and BS 8110 give least conservative predictions. Two theoretical methods provide moderately conservative predictions. Both codes of practices and theoretical methods have their own merits and demerits in the design of slender columns. With the growing use of slender reinforced concrete columns, more research should be carried out in order to study the behavior of slender reinforced concrete columns.
DRNTU::Engineering::Civil engineering::Structures and design
Final Year Project (FYP)
Nanyang Technological University