Strength

Eucalyptus is significantly stronger than oaks and mixed hardwoods in measurements of bending strength, shear, hardness and related measurements.

Why does strength matter? In general, stronger materials yield stronger results. Stronger materials are especially important in engineered lifts (e.g., wind turbine crane lifts) or in repeated stress on the mat. Strength also matters in predicting mat longevity. Stronger materials generally mean longer lifespan, which is particularly important for lease fleets and for lowering your Total Cost of Ownership.  

Sources: Mobile Crane Support Handbook, 2nd edition. David Duerr. https://eucmat.is/Facts

But, this isn’t the whole story. 

Material strength depends on both species and material grade.

To clarify further: There is clear sample material strength and there is allowable design strength. Mat users want allowable design strength. It’s about 20% of the clear sample strength, and it tells us what kind of machinery and load we can put on the mat under different ground bearing conditions.

For example, in the United States Select Structural is the highest grade for timbers. 

Timbers are 5″x5″ and larger. 

Mixed oaks are a class of species under the American Wood Council’s National Design Specification (AWC NDS). Bending strength for Select structural mixed oak = 1250 PSI but #1 is 1000 PSI and #2 is 575 PSI.

Sometimes species that are not listed in the AWC NDS, for example, Poplar are still used for mats. It gets a little trickier here; you have to interpolate based on a different set of data. 

For more details see: https://eucmat.is/stronger

Field Applications:

1. Consider specifying mat strength rather than dimension. For example, a 6.75” thick Eucalyptus mat has about the same bending strength as an 8” Select Structural mixed oak or mixed hardwood mat. If you are getting #1 or #2 timbers, that Eucalyptus mat might be a 5″ or 6″ mat for equivalent bending strength.
2. If you are engineering lifts or are working on particularly poor soils you may find that a single Eucalyptus mat is equivalent to two mixed hardwood mats.
3. For transmission work you may find a 4″ or 5″ mat provides sufficient strength given typical loads. Check out this article on testing 6″ mats for strength against concrete trucks.
4. For solar work you may find that a 4” thick Eucalyptus mat (roughly equivalent to a ~5″ mixed hardwood mat) has sufficient strength to support typical machinery weights.
5. If you use laminated mats – three-ply bolted or glue-line mats: A ~4″ Eucalyptus mat is roughly equivalent to a five-ply 6 7/8th inch lam. Best explained visually. Book a short call for the details.