In the design of reinforced concrete (RC) beam-columns, provisions in some buildings codes and standards stipulate that if the slenderness of such members is less than a certain lower limit, the second-order effect can be neglected and the member is designed based on its cross-sectional capacity. Even though such lower limits were originally based on columns made of normal-strength concrete (NSC), the lower limits are presented in these codes and standards even for columns made of higher-strength concretes (HSCs). The current study investigates the applicability of such lower limits for HSC. A nonlinear finite element model of RC columns is developed using ANSYS and validated against published test data, and is then used to construct interaction axial-moment (P-M) diagrams for slender RC columns considering both material and geometric nonlinearities. The lower slenderness limit for sway-inhibited columns is re-established based on the finite element results and compared to the limits provided in codes and standards. Also, the elastic solution is used with essential modifications to study the trend of behavior and its results are also compared to the finite element results. The study found that the limits given in the ACI Code and Eurocode are generally conservative for NSC columns but not for HSC, especially for the case of equal end moments with single curvature. Using the finite element results, a new limit for the lower slenderness for HSC columns is proposed

Title

ACI Structural Journal

Publisher

ACI

Publisher Country

United States of America

Indexing

Thomson Reuters

Impact Factor

1.197

Publication Type

Both (Printed and Online)

Volume

115

Year

2018

Pages

1-10