Examining the shear strength of the glue lines in glued laminated timber

Abstract

With a soaring global population and continuous depletion of resources, wood and engineered wood products will change the way we carry out conventional construction. Conventional building materials such as concrete and steel have temporarily controlled the construction market but wood is making a serious comeback. Evolving building codes is facilitating this shift as they are allowing larger timber structure to be built. There are numerous benefits in using wood as a building material and historically wood has been used for just everything as it is still today. At the forefront of this shift are engineered wood products. This study focuses on the shear strength of the glue lines within glulam bolts constructed of Picea mariana Lamb. pieces from the Quebec based glulam facility, Nordic. Roughly twenty replicates were obtained from five glulam bolts for a grand total of ninety-seven samples tested for shear strength on the glue line. It was hypothesized that there would be no difference in shear strength between the five bolts. This hypothesis was rejected as the results showed that average peak load for the tests was 21,354.59 N and the presence of significant differences in average peak load between bolts. These results are congruent the published value for shear strength (21,920 N) in clear black spruce, which means that the glue lines did not have an affect on shear strength. The significant differences between bolts may be explained by the inherent variability of wood.