A column may be defined as a vertical structural member subjected to axial loads, whose length is more than twice the least lateral dimension. Reinforced concrete columns are used to transfer the load of the structure over to its foundations.
It may be necessary to have a few R.C.C. columns even in a small building. The size and shape of the column will be determined by architectural considerations. For individual columns, a minimum of four bars are to be used. However, if the load on the column is very less and columns are provided more from architectural point of view, 4 nos. of 10 mm diameter bars may be provided. The consideration for the minimum size of a bar is that it should be stiff enough to stand up straight inside the formwork during concreting. The horizontal binders spaced at horizontal intervals of 15 cm to 23 cm help to keep the column reinforcing bars stiff and straight by holding them together. 16 G Black wire is used for tying. The binders pass round the outside of the main bars and are anchored by hooking the ends over one of the bars.
When a column is required to be continued beyond a slab or through a beam, the main bars of the column must pass through slab or beam which frame up the column.
