A Parametric Design Framework for Timber Framing Span Tables

Structural sawn timber is widely utilised in timber-framed residential housing, however, a range of short and long-term supply chain pressures are causing market demand to significantly out-pace the available supply. This paper examines how existing timber framing span tables, can be improved to reduce the over-specification of timber products in housing construction and thus improve supply utilisation. A novel parametric design framework is proposed that creates structured and indexable span data sets from the decoupled evaluation of structural member capacities and building design actions. The framework is implemented for five timber wall frame element types; generated data is verified against existing span table data published as supplements to Australian Standards for residential timber-framed housing. The developed framework and digitised span data are then used to investigate how span capacity is influenced by revisions to building practice and to develop alternate span table formats that facilitate cross-grade comparison and minimum-grade specification.