Abstract
This paper describes a nonlinear numerical investigation into the inelastic cyclic response of hybrid steel moment frame members with cross-laminated timber-steel floors. Continuum models of reduced beam section steel moment connections, timber beams and steel-timber interfaces were constructed to validate the numerical procedures. Steel-timber beam and external beam-to-column connection models were then constructed to evaluate the composite action and the influence of the timber slab on the cyclic response, respectively. In the beams, the composite action was modelled using connectors corresponding to screwed steel-timber shear connections, as well as with full interaction. For the beam-to-column connections, screwed shear connections were considered only outside the region where plastic hinging was expected, and the slab was modelled with or without a gap around the steel column. The results from beam modelling show that the degree of shear connection was 74% on average. For the steel-timber connections, there was an average increase in positive moment capacities of 1.5% and 15.2%, for the cases with and without a gap in the slab, respectively, compared to the steel counterpart. Removing the shear connectors from the reduced beam section region and including a gap around the column, enable a cyclic response dominated by the steel beam. The observations from this paper offer insight into the response of hybrid steel-timber floors under lateral loading.