KCR-waarde – BuildSoft Support https://support.buildsoft.eu/fr/ BuildSoft Support Tue, 22 Sep 2026 15:16:48 +0000 fr-FR hourly 1 https://wordpress.org/?v=6.2.13 DT EC [G1] 01: Shear https://support.buildsoft.eu/fr/knowledge-base/dt-ec-01-shear/ Thu, 13 Mar 2025 09:19:39 +0000 https://support.buildsoft.eu/?post_type=ht_kb&p=14904 Description

Geometry Cross-section: 70x221mm
Material: C24
Load ULS FC: 7.16kN
Standard EN 1995-1-1 [- -]
Design parameters kmod: 0.8

Independent reference results

Open handcalculations

According to EN 1995-1-1 §6.1.7 (1)P the shear check implies:

    \[\tau_d \leq f_v_._d\]

with

  • \tau_d the design shear stress
  • f_v_._d the design shear strength (= a material property)

From any course on mechanics, you can find that the maximal shear stress in a rectangular section equals:

    \[\tau_d=\frac{3 \cdot V_E_d}{2 \cdot A}\]

Combining both equations gives:

    \[ \frac{3 \cdot V_{Ed}}{2 \cdot A} \leq f_v_._d\]

or

    \[V_{Ed} \leq \frac{2 f_v_._d \cdot A}{3} \]

The area A of a rectangular section equals b \cdot h:

    \[V_{Ed} \leq \frac{2}{3} b \cdot h \cdot f_v_._d \]

Yet the addendum EN 1995-1-1/A1:2008 §6.1.7 (2) states that the effective width b_{eff} = b \cdot k_{cr}; should be used instead of the width b to take the influence of cracks into account. Addendum EN 1995-1-1/A1: 2008 for solid and glued laminated timber, k_{cr}= 1.0 for all other wood based products.

    \[V_{Ed} \leq \frac{2}{3} \cdot b_{eff} \cdot h \cdot f_{v.d}\]

    \begin{align*} UC&= \frac{V_{Ed}}{\frac{2}{3} \cdot k_{cr} \cdot b \cdot h \cdot f_{v.d}}\\ &= \frac{V_{Ed}}{\frac{2}{3} \cdot \frac{2}{3} \cdot b \cdot h \cdot f_{v.d}}\\ &= \frac{7.2 \text{kN}}{\frac{2}{3} \cdot \frac{2}{3} \cdot 70 \text{mm} \cdot 221 \text{mm} \cdot \frac{4 \text{N/mm²}}{1.3}}} \\ L_{eff}&= \frac{L}{C_1} +2 \cdot h \text{ general case}\\ \end{align*}

    \begin{align*} UC &= \frac{V_{Ed}}{\frac{2}{3} \cdot k_{cr} \cdot b \cdot h \cdot f_{v.d}}\\ &= \frac{V_{Ed}}{\frac{2}{3} \cdot \frac{2}{3} \cdot b\cdot h \cdot f_{v.d}}= \frac{V_{Ed}}{\frac{2}{3} \cdot \frac{2}{3} \cdot b\cdot h \cdot \frac{k_{mod } \cdot f_{v.k}}{\gamma_m} }\\ &= \frac{7.16kN}{\frac{2}{3} \cdot \frac{2}{3} \cdot 70 \text{mm} \cdot 221 \text{mm} \cdot \frac{0.8 \cdot 4 \text{N/mm²}}{1.3}}\\ &=42.3 \% \end{align*}

Diamonds results and comparison

Strength verification of the beam according to EN 1995-1-1. At the end of the bar, the shear is decisive. In the middle of the beam it’s bending.

Intermediate results in Diamonds for lateral torsional buckling

Results Independent reference Diamonds Difference
Unity check 42.3% 42.1% -0.47%

References

  • EN 1995-1-1: 2005 + AC: 2006
  • Addendum EN 1995-1-1/A1: 2008
  • Tested in Diamonds 2026.
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