Name of Hand Note :- Selection of Column Dimensions
Page Length :- 03
The column dimension is selected based on the structural strength related constraints, along with satisfying the architectural requirements. Thickness of the non-load bearing wall used inside the floor will decide the width dimension of the column. The size of the girder that is supported on the columns will also decide the size.
The type of slab is also important in deciding the dimensions of column. Take the example of flat slabs in which the column will be having a greater dimension, as they must bear additional load without the beams. The column used in the conventional slab to beam load transfer arrangement will have reduced size.
The structural design of columns under axial loading suggests the use of permissible strength of concrete , steel area percentage pt and yield strength of steel fy. The strength contributed by the concrete is equal to .
The square or rectangular column is selected under small loads. The circular column with its spiral reinforcement is used to bear huge loads, as they have higher strength in buckling. One of the dimension is usually fixed based on the beam section supported, the slab thickness, wall thickness, etc. The ratio of width to depth should be restricted to 2 in case of rectangular columns.
The reinforcement area is determined, once the cross-section dimensions are fixed.
Here, the factored axial load is to be taken as nominal value of Pn.
The cross section dimension of column will be fixed using the same procedure under combined axial and bending loads.