Compression strength perpendicular to grain of structural timber and glulam

The characteristic strength values for compression perpendicular to grain as they appear in EN 338 (structural timber) and EN 1194 (glulam) are currently up for discussion. The present paper provides experimental results based on EN 1193 that may assist in the correct assignment of such strength values.

The dominant failure mode of glulam specimens is shown to be fundamentally different from that of structural timber specimens. Glulam specimens often show tension perpendicular to grain failure before the compression strength value is reached. Such failure mode is not seen for structural timber. Nonetheless test results show that the levels of characteristic compression strength perpendicular to grain are of the same order for structural timber and glulam.

The values are slightly lower than those appearing in EN 1194 and less than half of those appearing in EN 338. The paper presents a numerical analysis to prove the significant role of tension perpendicular to grain stresses in the failure mode of the glulam specimens.