Nonlinear Analysis and Comparison of Design Methods for Slender Concrete Columns with their Impact on Economy and Reliability

Abstract

The subject of this article is a comparison of the calculation methods for slender reinforced concrete columns, which are likely to lose stability, and therefore it is necessary to take into account the influence of the second order theory. The columns were calculated by the nominal curvature method [1] Chap.5.8.8 and the general nonlinear method [1] Chap.5.8.6 (3). Our comparison was aimed on the reliability of the design of the columns and the cost of the column. The analysis was made for the columns we selected from the halls built in practice. For this reason, we have asked for co-operation with Statika Čížek s.r.o.. This company has designed lot of hall objects during numerous years of its practise. In this study, we proposed a selected column located in a particular hall object. Parameters of the selected column have been slightly modified against the practical design. Reinforcement of selected column was designed using the curvature method. This proposal was then subjected to "optimization", where the task was to minimize the amount of concrete and minimize the amount of reinforcement with usage of a general nonlinear method. Then we compared the results of this analysis in terms of reliability and cost of production. This article aims to alert authorized engineers to be careful with usage of the general non-linear method in practice. It is questionable, whether saving money on the cost of building structure is worthwhile to design columns with significantly lower reliability. Sometimes even with the risk of a loss of stability that belongs to the category - brittle failures

Experimental Verification of Slender Reinforced Concrete Columns Design

“…That means the mean material properties should be used, and the uncertainties of failure shall be taken into the account. [9], [10].…”

Reliability Analysis and Comparative Study of Ordinary Concrete and High Performance Concrete Filled with Steel Tube under Axial Compression

“…This method leads in most cases to unjustified dimensioning. The deterministic method allows the engineer to carry out simple applications and to give solutions that are happily satisfactory from a safety [21][22][23][24][25][26][27][28]. Nevertheless, they do not give information on the real safety margin or the impact of various design factors on the structure's reliability.…”