ABC – Bending Strength MOR, Technology Keys

“The strength of wood samples in air dry condition (12% MC) is used for sorting and comparing species into the ranges  shown below. These ranges or Technology Keys were used by the original database.

The Modulus Of Rupture in bending (MOR) is a rough estimate of the ultimate bending strength of timber based on defect-free samples  of 20×20 mm sized sample of the transverse section of a piece of timber. However, in practice the modulus of rupture and other strength properties of a piece of construction timber are influenced by many factors such as wood defects, moisture content, load position and duration, among other. So, this is NOT a design value. It is expressed in kilograms force per square centimeter (kgf/cm2).

Low: Less than 580 (kgf/cm2)
Medium: 581 up to 685
Fairly high:  686 up to 808
High: 809 up to 956
Very high: 957 up to 1160
Extremely high: Over 1161 (kgf/cm2) “