Experimental study on partial compression parallel to grain of solid timber
Journal article, 2021

This paper describes results and analysis of experimental testing of entire and partial compression strength and stiffness parallel to the grain of solid timber (Japanese cedar). To investigate the spreading effects, the size effect of strength and stiffness, and the mechanism of the damage zone located close to the loading plates, tests on 90 specimens were performed. As a result, it was observed that damage zones existed near the loading plates. The observed spreading effects in the compression parallel to the grain were very small which justifies neglecting them regarding strength and stiffness. Although a presence of a size effect of the compression strength parallel to the grain of glulam specimens with knots was reported, the compression strength parallel to the grain of solid wood specimens without knots does not have a size effect. The height and width of the cross-section of the specimens have an influence on the damage zones and, hence, on the effective modulus of elasticity of the full height of the specimens. The compression strength has a correlation with the density of the timber and the width of the annual rings.

Size effect

Modulus of elasticity parallel to grain


Spreading effect

Compression parallel to grain

Damage zone


Marina Totsuka

University of Tokyo

Robert Jockwer

Chalmers, Architecture and Civil Engineering, Structural Engineering

Kenji Aoki

University of Tokyo

Masahiro Inayama

University of Tokyo

Journal of Wood Science

1435-0211 (ISSN) 1611-4663 (eISSN)

Vol. 67 1 39

Subject Categories

Wood Science

Other Materials Engineering

Other Civil Engineering



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