Reliability assessment of high-strength concrete columns

This study represents one of the first few attempts to systematically assess the reliability of high-strength concrete (HSC) columns designed according to the American Concrete Institute (ACI) Code provisions. In this study, the reliability of both short and slender HSC columns is assessed using a hybrid probabilistic approach. This approach combines Monte Carlo simulation with a first order reliability method. The reliability of 48 reinforced concrete columns designed according to the ACI Code is evaluated. The effects of the concrete compressive strength, amount of confining steel, amount of longitudinal steel, slenderness, and live to dead load ratio are examined. Numerical examples demonstrate that the reliability of short HSC columns is lower than that of the corresponding normal-strength concrete columns. Larger amounts of longitudinal steel have a beneficial effect on column reliability, especially in the case of slender columns. In addition, at small eccentricities, the reliability of HSC slender columns is generally higher than that of the corresponding short columns. Finally, it is demonstrated that at large eccentricities, very low reliability levels may be found for the combination of high concrete compressive strength, minimum amount of longitudinal steel, and high slenderness ratio. Based on these findings, design recommendations are suggested.