2.6.4.10 Check of rebar diameter

Check of rebar diameter

The rebars' limit diameter max d_s is checked according to EN 1992-1-1, Equation (7.6N) (see Equation 2.72).

At the top side of the plate, the program determines the maximum bar diameter d*_s,-z,φ1 of the first reinforcement direction depending on the stress available in this direction. In the check for the limitation of the steel stress, this stress was calculated as σ*_s,-z,φ1 = 208.18 N/mm². Together with the selected crack width w_k = 0.3 mm, the following limit diameter d*_s,-z,φ1 is obtained in Table 7.2N by interpolation:

$d_{s,-z,{\varphi }_1}^{*} = 25 + \frac{25 -16}{200 - 240} · \left(208.18 - 200\right) = 23.16 \text{mm}$

The limit diameter d*_s,-z,φ2 for reinforcement direction 2 is analogously determined from the tension stress σ*_s,-z,φ2 = 167.09 N/mm² and the crack width w_k = 0.3 mm:

$d_{s,-z,{\varphi }_2}^{*} = 32 + \frac{32 - 25}{160 -200} · \left(167.09 - 160\right) = 30.76\text{ mm}$

With the limit diameters d*_s for the two reinforcement directions and the respective steel stresses, the maximum bar diameters d_s are determined.

$d_{s,max,-z,{\varphi }_1} = 23.16 · \frac{2.9}{2.9} · \frac{0.4 · 100}{2 · \left(200 - 170\right)} = 15.44 \text{mm }$

$d_{s,max,-z,{\varphi }_2} = 30.76 · \frac{2.9}{2.9} · \frac{0.4 · 100}{2 · \left(200 - 158\right)} = 14.65 \text{mm}$

Rebar diameters d_s = 12 mm are respectively provided for both reinforcement directions. Thus, the check criterion for the governing reinforcement direction φ₁ is obtained as:

$\frac{d_{s,\text{exist},-z,{\varphi }_2}}{\text{max} d_{s,-z,{\varphi }_2}} = \frac{12.0}{14.65} = 0.819$