# Shear Area Types and Their Meaning

### Tips & Tricks

000966

27 January 2015

If you look at the cross‑section properties of the metal category, you can see that there are three types of shear area, whose meaning and calculation are described here.

• Shear area
• Shear area according to EC 3
• Plastic shear area

#### Shear area

The shear area is required for determination of the elastic deformation due to shear forces. The formula for calculating the shear area is shown in Figure; detailed information can be found in the RFEM manual, Chapter 4.13, and RSTAB manual, Chapter 4.3.

Important: Elastic shear stresses cannot be determined by means of the shear area, but with the formula τ = V × S / (I × t). The relationship between shear areas and shear stresses are described in Petersen: Steel Construction.

#### Shear area according to EC 3

This type of shear area is used to determine the plastic shear capacity of a cross‑section. In EN 1993‑1‑1, 6.2.6 (3), you can find the formulas for various cross‑section types in order to calculate the effective shear areas.

#### Plastic shear area

This is a simplified entry for determination of the plastic shear capacity. You can easily generalize it as the cross‑section is divided into rectangular elements. Fillets and elements of the transverse force direction are neglected. Inclined elements will be considered with regard to the angle.

The stand‑alone program SHAPE‑THIN performs the calculation of the plastic shear areas according to the same method.