Structural Behaviour of Aluminium-Timber Composite Beams with Partial Shear Connections

In this paper, the short-term behaviour of innovative aluminium-timber composite beams was investigated. Laminated veneer lumber panels were attached to aluminium beams with screws. Recently conducted theoretical, experimental, and numerical investigations have focused on aluminium-timber composite beams with almost full shear connections. However, no experiments on aluminium-timber composite beams with partial shear connections have yet been conducted. For this reason, composite action in composite beams with different screw spacing was studied in this paper. Four-point bending tests were performed on aluminium-timber composite beams with different screw spacing to study their structural behaviour (ultimate load, mode of failure, load versus deflection response, load versus slip response, and short-term stiffness). The method used for steel-concrete composite beams with partial shear connection was adopted to estimate the load bearing capacity of the investigated aluminium-timber composite beams. The resistance to sagging bending of the aluminium-timber composite beams with partial shear connections from the theoretical analyses differed by 6-16% from the resistance in the laboratory tests. In addition, four 2D numerical models of the composite beams were developed. One model reflected the behaviour of the composite beam with full shear connection. The remaining models represented the composite beams with partial shear connections and were verified against the laboratory test results. Laminated veneer lumber was modelled as an orthotropic material and its failure was captured using the Hashin damage model. The resistance to sagging bending of the aluminium-timber composite beams with partial shear connections from the numerical analyses were only 3-6% lower than the one from the experiments.