Study of failure of concrete columns , failure mechanisms and comparison of spiral helix, DNA Helix(simple), DNA Helix(rubber at middle), & DNA helix(rubber at end)

Abstract

Reinforced concrete column is a compression member and transfers the loads from structure to the ground through foundations. There are three types of concrete columns based on its height and lateral dimension. Long columns are those whose ratio of height to least lateral dimension is more than 12. When the height to least lateral dimension is less than 3, it is called a pedestal and if it is between 3 and 12, it is called as a short column. The load carrying capacity and modes of failure of a reinforced concrete column is based on the slenderness ratio. Slenderness ratio is the ratio of the effective length Le and least lateral dimension of the column as per Indian and British Standards. But as per American Concrete Institute Code of Practice, the slenderness ratio is defined as the ratio of effective length of column to its radius of gyration, which is same as used for structural steel design as per IS Code. Effective length of a column depends on its support conditions at ends. Based on the slenderness ratio of the column, there are three modes of failure of reinforced concrete columns. The columns are assumed to be centrally loaded (no eccentric loads).