Investigation on the Strain Effect on the Behaviour of Laminated Veneer Lumber Timber Connections

This paper experimentally investigates the influence of the strain rate experienced during earthquake and progressive collapse events on mechanical properties affecting the design of softwood Laminated Veneer Lumbers timber connections. The parallel and perpendicular to grain embedment stiffness and strength, and the Mode I and II fracture energies were examined under four levels of strain rates. Results showed that the embedment stiffness and strength increased by up to 35% from the quasi-static to dynamic strain rates while the embedment ductility decreased by up to 17%. The fracture energies were found to be mostly insensitive to the investigated range of strain rates. Furthermore, the influence of the strain rate on the behaviour of timber connections is further analysed by quasi-statically and dynamically testing one connection type with two different fastener spacings. Results showed that for the connections investigated, the dynamic strength can be up to 30% higher than the quasi-static one, however, the dynamic ductility of the connections can be reduced substantially by up to 32.5%.