Mechanical performance of timber connections made of thick flexible polyurethane adhesives

This study investigates timber connections with flexible polyurethane adhesives, which prove to have the potential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental results on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.