Design of slender reinforced concrete rectangular columns subjected to eccentric loads by approximate methods

Reinforced concrete codes worldwide establish that the design of slender columns must ensure that under the most unfavorable load combination, there is neither instability nor material failures. Thus, it is mandatory to consider material as well as geometrical nonlinearities. The consideration of second order effects can be done using simplified methods or the general method. This work analyses second order effects based on the approximate methods shown in NBR 6118 [1]: approximate curvature method and approximate stiffness procedure. Due to the importance of the columns in the stability of buildings is essential that these simplified design methods provide safe solutions for the design of columns. In this scenario, the objective of this study is to evaluate these simplified design procedures in terms of safety, precision and economy with respect to test results of RC slender columns subjected to eccentric loads found in the literature. The comparative analysis reveals that the approximate stiffness procedure provides better results.