Mechanical Properties of Machine Stress Graded Sawn Timber Depending on the Log Type

Abstract

This article presents the results of tests conducted on Scots pine timber from three different kinds of logs: butt, middle and top. A planed pine timber batch composed of 510 pieces, dried to ca. 12% humidity, was machine-graded using a portable MTG device, and classified into the following classes: C18, C24, C30, C35 and C40 (according to EN 338:2016). During the second stage of the study, the timber was tested to determine its density, MOE and MOR, in accordance with EN 408:2012. We analyzed the impact of the timber’s log of origin on the results of machine strength grading and on the values of correlation coefficients between the tested properties. The results show, among others, that there is a correlation between the C classes and MOR of the tested timber, as well as its origin from butt, middle or top logs.