Formula 5

\begin{array}{l} f_{ax, k} = 0.52 \cdot \emptyset^{- 0.5} \cdot l_{ef}^{- 0.1} \cdot ρ_{k}^{0.8} = 0.52 \cdot 8 {mm}^{- 0.5} \cdot 90 {mm}^{- 0.1} \cdot 350^{0.8} = 11.27 N / {mm}^{2} \\ F_{ax, Rk} = \frac{n_{ef} \cdot f_{ax, k} \cdot d \cdot l_{ef} \cdot k_{d}}{1.2 \cos^{2} α \sin^{2} α} = \frac{11.27 \cdot 8 mm \cdot 90 mm \cdot 1}{1.2 \cos^{2} 30 \sin^{2} 30} = 7.96 kN \\ f_{tens, k} = 20 kN \\ f_{c, k} = 50 kN \end{array}

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