Strength of eccentrically loaded slender columns made with high-strength concrete

Abstract

A non-linear finite-element analysis model was developed to predict the strength of high-strength concrete (HSC) slender columns. The studied parameters were compressive strength, load eccentricity, slenderness ratio and longitudinal and transverse reinforcement ratio. The model results were verified by comparison with analytical results and experimental results reported in the literature. A parametric study was also carried out by comparing the model results with those obtained using design codes, which were predominantly based on data derived from tests on normal-strength concrete. The model proved to be a suitable tool for the strength analysis of slender HSC columns. ACI 318-14 gave the most conservative predictions of the load-carrying capacity of centrally loaded columns but was close to the model results for eccentric loading. The procedures specified by BS EN 1992-1-1:2004 resulted in a significant underestimation of the load-carrying capacity of slender columns, particularly for eccentric loading, and this increased with greater slenderness ratios. This is probably because the confinement index taken into consideration in the software was not consistent, ranging from 0·03% to 5·14%. It was concluded that special clauses need to be introduced in the design codes for the accurate design of HSC columns.