Design and optimisation of timber-framed structures using a stock of reclaimed elements

Abstract

The reuse of reclaimed timber in structural applications is limited by irregular geometries and mixed material properties, posing complex optimisation challenges. This paper presents a computational framework for designing timber-framed modular buildings from mixed reclaimed material stock. It combines a set-based stock allocation method with an integer linear programming optimisation, where cutting and jointing patterns are decision variables. Two case studies demonstrate the framework, including the construction of multiple modular houses using nearly two kilometres of recycled timber. A globally optimal solution for six houses was found in under 1.5 s, using 760 parts with 77.6% stock utilisation and 83.7% cutting efficiency. Compared to existing stock-constrained structural design tools, the framework expands capability by handling mixed grades, stock allocation across structural subsystems, and enabling cutting and jointing into shorter, longer, or laminated members. It further allows near-real-time optimisation of materially efficient part arrangements within framed structural systems.