Failure of Slender Concrete Columns Due to a Loss of Stability

The European standard for the design of concrete structures that are likely to lose stability requires taking into account the effects of second order theory. This effect increases the impact of a bending moment due to member deformation and additional eccentricity. Slender members can be calculated by the use of a non-linear method. This approach shows a deficit in global reliability for cases where the concrete columns fail due to the loss of stability before reaching the design resistance in the critical cross-sections. Buckling is a brittle failure which occurs without any warning, and the probability of its formation is markedly influenced by the slenderness of the column. Here, the calculation results are presented and compared with the results from an experiment which was carried out in cooperation with STRABAG Bratislava LTD at the Central Laboratory of the Faculty of Civil Engineering SUT in Bratislava. The columns were designed according to the methods stated in STN EN 1992-1-1, namely, a general non-linear method. The focus of this study is to compare multiple approaches based on codes used in Germany (DIN 1045-1, 2001) and Austria (ÖNORM B 4700, 2001) with the present European code mentioned above. The paper aims to compare the global reliability of slender concrete columns with variable slendernesses of 90 and 160.