EN 14272:2011

Foreword
1 Scope
2 Normative references
3 Principle
4 Terms and definitions
5 Symbols
6 Calculation method
7 Characteristic values for strength and stiffness in
   bending, tension and compression
8 Shear properties
9 Ratio of strength upon modulus
10 Density
11 Conversion from strength and modulus of elasticity to
   capacity and stiffness
Annex A (normative) - Derivation for the veneer values (or
        basic values)
Annex B (normative) - Practical spreadsheets to derive the
        properties
Annex C (informative) - Example of bending strength
Bibliography

This European Standard specifies, for plywood panels of any composition, symmetrical or not, a calculation method to derive some mechanical properties (strength and stiffness in bending, tension, compression, panel and planar shear) as well as density from the wood compounding the layers.NOTEUsually, the lay-up of the panels is symmetrical but, very often, the surface appearance of the face and the surface appearance of the back face differ, hence a difference between the mechanical properties of the respective veneers. Therefore, in this case, the composition is not mechanically symmetrical and a symmetry independent calculation method is needed. Provided that structural characteristic values are taken for the layers, the resulting values for the panels can be used as characteristic values as required by EN 1995-1-1.Conversely, Annex A defines the procedures to derive the veneer properties, in bending, tension and compression, either from testing panels according to EN 789 and EN 1058 or from timber testing according to EN 408 or from imposed values defined in EN 338.Annex B provides practical spreadsheets, which are applications of the equations in the main part of this standard.Annex C provide an example for the calculation of bending strength, in accordance with Annex B.