Title: Design of slender RC columns according to Eurocode and Polish code compared with the improved numerical method

Author(s): K. Klempka, M. Knauff

Publication: KILW

Volume: 51

Issue: 1

Appears on pages(s): 23-42

Keywords: design,eurocode,slender columns

DOI:

Date: 1/1/2005

Abstract:
This article describes the improved method of numerical calculation of load bearing capacities of slender RC columns. The improved method is based, as much as possible, on the fundamental assumptions of Eurocode concerning properties of concrete and steel as well as methods for calculating the stress-strain relation and curvature. In the first step the increase of the moments (II order theory) due to short-term and long-term deformations caused by the long-term loading in the limits of linear creep of concrete are taken into-account. Then the short-term loading is increased and the ultimate moment according to the II order theory is calculated. Calculations are done taking into account step-by-step analysis of the consecutive increments of loading, strain and, resulting from them, changes in the column's stiffness. The results of the calculations obtained using the improved method were compared with the columns' load bearing capacities calculated according to Eurocode and Polish codes. The main emphasis was put on the analysis of the influence of slenderness and creep. Numerous comparisons of the results show that in case of B20 concrete, methods based on nominal stiffness (PN02, EC2/02I) are well-calculated. In case of B60 concrete, the results of these methods are incompatible and only load-bearing capacity calculated according to Eurocode (EC2/02I) is not greater than the one calculated according to the improved method. The least credible was the nominal curvature method (EC2/02II); load baring capacity calculated according to this method may be larger than the one calculated according to the improved method.