7 A Tsection with its centroidal axis x is shown in Figure 7

7. A T-section with its centroidal axis x is shown in Figure 7. All thicknesses are 30mm. Determine the second moment of area la about the x-axis passing through the centroid. 300mm centroid Figure 7

Solution

I_xx = I_xx of flange + I_xx of web

=( 300 x 30³ / 12 + 300 x 30 x (400 - 274.6 - 30 / 2)² )

+ (30 x (400 - 30)³ / 12 + 30 x (400 - 30) x ( 274.6 - (400 - 30) / 2)²)

= 326113516 mm⁴