SEDL / STP / STP691-EB / STP36120S

Effect of Accelerated Aging on Tensile Perpendicular-to-Glueline Strength of Glued-Laminated Beams

Sandoe, MD
Research associate and associate professor, University of Toronto, Toronto, Ontario

Keenan, FJ
Research associate and associate professor, University of Toronto, Toronto, Ontario

Beall, FC
Scientific specialist, Weyerhauser Company, Tacoma, Wash.

Fox, SP
Research scientist, Western Forest Products Laboratory, Vancouver, B.C.

Pages: 11    Published: Jan 1980

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Abstract

Several glued-laminated beams of both conventional and “hot-press” manufacture were removed from service and exposed to several cycles of alternating high (85 percent) and low (35 percent) relative humidities at 50°C in an attempt to predict long-term durability of the gluebonds. Residual glueline strength, as measured by a flexural specimen loaded to induce tensile stress perpendicular to the glueline, was more variable and significantly lower for hot-press material. Residual strength of hot-press gluebonds varied with longitudinal position in the beam, with minimum strengths found in the region where maximum bending under in-service loads occurred. The tension perpendicular-to-glueline flexure specimen is suggested as a more sensitive indicator of gluebond integrity than the standard shear-block specimen.