Strength and local deformability of wood beneath bolted connectors

In this paper, the problem of the local resistance of wood beneath a bolt connector subjected to shear is studied both in the case of load parallel to the grain and perpendicular to the grain. Two specific test methods were adopted in order to study the influence of lateral confinement. Thin plate specimens of glued laminated wood pierced through by a steel bar (16 mm diameter) were considered to simulate a real situation. From the load-slip curves, the initial stiffness and the embedding strength of wood beneath the connector were estimated. Moreover, the geometric interferometry technique made it possible to obtain the entire field of displacements in the wood surrounding the bolt. Comparisons of test results with existing data are in good agreement for specimens without confinement. Confined specimens show a slight increase in bearing capacity for load parallel to the grain and a significant increase of the ultimate bearing capacity for load perpendicular to the grain. Negligible differences were noted in deformability.