1 -Determine the properties of the concrete column:

Cross-sectional dimensions: Measure the width and depth of the column.

Material properties: Determine the compressive strength of the concrete and the yield strength of the reinforcing bars used in the column.

2 - Calculate the effective axial load:

Determine the applied axial load on the column.

Consider any additional loads or moments acting on the column.

3 - Determine the strain and stress distribution:

Assume a stress-strain relationship for the concrete, such as the Mander stress-strain model.

Calculate the strain distribution along the height of the column using the applied axial load and the moment distribution.

4 -Calculate the concrete and steel contributions:

Determine the stress in the concrete and steel using the strain values obtained in the previous step.

Consider the concrete and steel contributions to the total axial capacity of the column.

5 - Plot the Mander curve:

Using the stress values obtained, plot the stress-strain curve for the concrete and the steel.

The Mander curve represents the interaction between the concrete and steel, showing the capacity of the column at different levels of axial load and bending moment.