Centroid of I-section

The I-section, shown in Figure 11.2, can be divided into three parts—lower part of area A₁, middle part of area A₂, and upper part of area A₃. The lengths and widths of all the parts of I-section are shown in Figure 11.2. Let the X and Y coordinates pass through origin O as shown in Figure 11.3.

Figure 11.2 Centroid of I-section

Figure 11.3 Reference Axes for I-section

The coordinates for centroid can be calculated using the following formula:

In the case of axial symmetry about Y-axis (i.e., y-axis passes through centres of sections 1, 2 and 3), the distances of X₁/2, X₂/2, X₃/2 from origin will be zero.

Hence,  = 0.