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