Paper number 854

COST VERSUS RELIABILITY IN REINFORCED HSC COLUMN DESIGN

Sofia M. C. Diniz¹

1Department of Structural Engineering, Federal University of Minas Gerais, Av. do Contorno 842, 20 Andar, Belo Horizonte, MG 30110-060 Brazil

Summary

High-strength concrete (HSC) can largely extend the advantages of reinforced concrete (RC) technology. In fact, HSC has found an increasing utilization, especially in the lower columns of high-rise buildings. From a deterministic viewpoint, it has been shown that the most economical column corresponds to the use of a minimum amount of longitudinal steel and the highest available concrete compressive strength. However, the most economical solution does not necessarily represent a reliable one. In this study, a decision analysis process for the case of axially loaded RC columns is presented. The weighted objective approach is employed; two main objectives are pursued: minimize costs and maximize column reliability. Probabilistic methods are used to define column reliability with respect to ultimate strength. Several combinations of concrete compressive strengths and longitudinal steel ratios are taken as the possible alternatives.

Keywords

reinforced concrete, high-strength concrete, columns, random variables, probabilistic methods, reliability, cost, decision process.