Prediction of the ultimate longitudinal compressive concrete strain at hoop fracture using energy considerations
Abstract
The fracture of transverse hoop reinforcement can lead to the collapse of a reinforced concrete column, as has been observed in concrete bridges and buildings attacked by severe earthquakes as well as in laboratory tests. To predict the longitudinal concrete strain at the stage of first hoop fracture a theoretical method based on considerations of strain energy referred to as "Energy Balance Theory" has been proposed by Mander et al. This paper reviews the "Energy Balance Theory" and then proposes several modifications for this theory based on a failure model of a reinforced concrete column subject to axial compression. These modifications take into account significant energy factors neglected in the theory by Mander et al and correct some unrealistic assumptions made in that theory. The predictions of the modified theory are then compared with the results obtained from concentric loading tests on 18 reinforced concrete columns conducted at the University of Canterbury and the validity of the modified theory is assessed.