Probabilistic Assessment of the Tension-Shear Failure Domain Interaction of Angle Brackets for Timber Structures

Angle brackets and hold-downs represent the typical metal fasteners in mass timber structures. Angle brackets are primarily designed to support shear forces and are generally placed near the panel's end cross-section centroid. In contrast, hold-downs are located at the panel edges to adsorb tensile and compressive forces. However, angle brackets can be subjected to axial and shear forces in the presence of boundary conditions that allow for rotation at the top of the panel. Therefore, the shear capacity of angle brackets can be compromised by the presence of a multiaxial stress state, especially under horizontal loads. In this study, the authors estimated the tension-shear failure domains for typical off-the-shelf angle brackets, taking into account the uncertainty of modeling, especially in the constitutive nail-timber interaction. The authors developed finite-element numerical models validated against experimental tests, aiming to estimate the exponents of the interaction domain while considering both modeling uncertainty and variability of the angle brackets. It was observed that the average interaction domains can be approximated as quadratic to linear domains depending on the angle bracket or nails' contribution to failure.