Load-Embedment Response of Timber to Reversed Cyclic Load
Keywords:Embedment test, timber joints, hysteresis loops, cyclic loading, strength degradation
AbstractOne of the most important properties governing performance of timber joints containing dowel-type fasteners is the embedment response of wood under the action of a loaded fastener. Previous investigations on load-embedment behavior of wood focused almost exclusively on monotonic loading condit ons. This paper describes a program of work to investigate the influence of wood density, fastener diameter, and loading characteristics on stiffness properties, ultimate strength, and strength degradation of load-embedment response of wood-based material when subjected to reversed cyclic loads. Mathematical functions were developed to describe both the envelope and hysteresis loops of the load-embedment response. A comparison of the model parameters reveals that initial stiffness and ultimate load increase with loading rate, wood density, and fastener diameter. Strength degradation occurs under both monotonic and cyclic loading for solid wood. The degree of strength degradation increases with any increase in loading rate, wood density, and fastener diameter, and presence of preloading history. No strength degradation occurs in plywood under either monotonic or reversed cyclic load.
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