Buildings, Vol. 16, Pages 2765: Study on the Shear Performance of Steel-to-Timber Glued-in Rod Connections

Buildings, Vol. 16, Pages 2765: Study on the Shear Performance of Steel-to-Timber Glued-in Rod Connections

Buildings doi: 10.3390/buildings16142765

Authors:
Miao Pang
Huan Gu
Jin Chen
Jinlong Pan

Glued-in rod (GIR) connections are widely used in timber composite structures owing to their high load-bearing capacity, high stiffness, and concealed configuration. However, their shear behavior and design methodology under lateral loading remain insufficiently understood. In this study, monotonic shear tests were conducted to clarify the shear failure characteristics and load-transfer mechanisms of steel-to-timber GIR connections. The effects of rod diameter, anchorage length, timber strength grade, and rod orientation relative to the timber grain on the shear performance of the connections were systematically investigated. Self-tapping screw (STS) connections were also tested to compare the shear capacity, deformation behavior, and failure modes of the glued-in rod connections. Based on Johansen’s yield theory and the observed failure modes, shear capacities, and load–slip curves, the shear capacity prediction method and the main influencing factors were evaluated. The results indicate that steel-to-timber GIR connections primarily exhibit a combined failure mode involving timber embedment crushing and rod bending deformation or shear fracture under monotonic shear loading. Shear capacity increases markedly with increasing rod diameter. For the 12 mm rods examined in this study, anchorage length has a limited effect on shear capacity once it exceeds approximately 10d. Connections with rods oriented parallel to the grain demonstrate higher load-carrying capacity and deformation capacity than those with rods perpendicular to the timber grain. Furthermore, the prediction accuracy of the Eurocode 5-based calculation method varies with rod diameter: the calculated capacities agree well with the experimental values for small-diameter rods (10 mm and 12 mm), whereas the predictions for larger-diameter rods (14 mm and 16 mm) are conservative.