# 8D.D.9 Calculation of Net Section Factor

The procedure for calculating the net section factor for an angle section is as follows:

• For a channel section, net section factor is taken to be 1.0.
• For an angle section, it is the ratio of the net effective area, Anet, to the gross area, where:

1. Single angle connected by only one leg

 Anet = A1 + A2 × K1

where A1 = net cross-sectional area of the connected leg A2 = gross cross-sectional area of the unconnected leg K1 = 3·A1/(3·A1 + A2)

The area of a leg of an angle = Thickness of angle × (length of leg – 0.5× thickness of leg)

2. Pair of angles placed back-to-back connected by only one leg of each angle to the same side of a gusset plate

 Anet = A1 + A2 · K1

where A1 = net cross-sectional area of the connected leg A2 = gross cross-sectional area of the unconnected leg K1 = 5·A1/(5·A1 + A2)

The area of a leg of an angle = Thickness of angle × (length of leg – 0.5× thickness of leg)

3. Double angles placed back-to-back and connected to each side of a gusset plate

• Anet = gross area minus the deduction for holes