Comparative study of the simplified methods of Eurocode 2 for second order analysis of slender reinforced concrete columns

Usually, reinforced concrete design codes indicate only one simplified method for second order analysis of slender columns. The Eurocode 2 (EC2), on the other hand, adopts two simplified methods: one based on nominal stiffness and other based on nominal curvature. It would be desirable that both methods could provide similar solutions. However, this is not the case, as shown in this paper. On the contrary, the two EC2 simplified methods can provide very different results, leaving the engineer uncertain about which method he should use. The objective of this work is to compare these two simplified methods presenting the contradictions between them. Several experimental results available in the literature have been analysed and compared. The method based on the nominal curvature showed to be the most accurate; therefore, it is suggested to be used.