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 outpace 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 are 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.

Automated summary

This paper explores improving timber framing span tables to reduce over-specification of timber products in housing construction and enhance supply utilization. A new parametric design framework is proposed to create structured and indexable span data sets, which are verified against existing span table data. The framework is used to investigate how span capacity is influenced by revisions to building practice and develop alternate span table formats.