Impact of a reinforcement treatment with acrylate impregnation on the mechanical behavior of black spruce as connector member

Abstract

As a previous study has shown, it is possible to increase by 50% the dowel bearing strength of black spruce with an acrylate formulation applied by impregnation. Three diameters of bolts and two orientations of loading were included in this study. The effect of treatment on the dowel-bearing strength appeared to increase while the diameter of bolt decreased. The orientation of loading was significant as the treatment had a major impact in the parallel to grain direction and no impact in the perpendicular direction. With the digital image correlation analysis, an expanded strain field perpendicular to the load direction was observed. The superior embedding capacity would help to reduce the dimensions of the timbers as well as the number of connections required in the building design. With an increase of ductility, wood connections show a safer yielding behavior.

Performance evaluation of a wood treatment for connections with dowel-type bolts

“…To optimize the strategy proposed by Lafond et al (2016Lafond et al ( , 2017, two wood treatments were used. Both treatments used a lower quantity of polymer for impregnation, a shorter wood treatment time, and a lower polymerization temperature of 20 ± 3 °C (room temperature) compared to the impregnation method used by Lafond et al (2017). The first treatment was the capillary impregnation method (T1), which is based on the penetration of a liquid into dry wood under the influence of capillary forces.…”

“…The movement of the moving crosshead of the MTS testing machine allowed the dowel displacement to be measured. Dowel-bearing strength (σmax) and the stiffness (ks) were determined using the methodology described by Lafond et al (2017). The ultimate loads and the loaddisplacement curve were recorded using TextWorks software (MTS System Corporation, Eden Prairie, MN, USA).…”

“…As the size of the buildings increases, fastener design is the significant limiting criterion in structural design. Consequently, the building system tends to lead to an oversized timber structure, which leads to limitations in architectural design (Lafond et al 2017). The connection areas are often considered a critical point for the dimensioning of a structure because the maximum stresses are located in these areas (CSA 086-19 (2019)).…”

“…The techniques for improving the dowel-type connection strength involve the study of friction between the contact surface of the fastener and wood, as well as the study of embedment performance through the improvement of the wood (Rodd and Leijten 2003). In order to study and improve the behavior of these connection types, several studies have been conducted (Gattesco 1998;Mungwa et al 1999;Sawata and Yasumura 2002;Pizzi et al 2006;Pantelides et al 2010;Franke and Magnière 2014b;Lafond et al 2016Lafond et al , 2017. Some research emphasized the improvement of mechanical performance of this type of connection through the wood modification using impregnation treatment (Lafond et al 2016(Lafond et al , 2017.…”

“…In order to study and improve the behavior of these connection types, several studies have been conducted (Gattesco 1998;Mungwa et al 1999;Sawata and Yasumura 2002;Pizzi et al 2006;Pantelides et al 2010;Franke and Magnière 2014b;Lafond et al 2016Lafond et al , 2017. Some research emphasized the improvement of mechanical performance of this type of connection through the wood modification using impregnation treatment (Lafond et al 2016(Lafond et al , 2017.…”