7. Calculation methods for mechanical strength

7.1 Simplified rules for calculating straight section properties

The standard proposes two simplified methods: the reduced cross-section method and the reduced properties method. For application in France, the National Annex has retained only the reduced cross-section method.

• Reduced cross-section method

  The effective cross-sectional area is obtained by reducing the initial cross-sectional area by the effective carbonization depth of _ef (figure 7 ) according to :

  $$d_{\text{ef}}=d_{\text{char},\text{n}}+k_0{d}_0$$