Inventory-Constrained Structural Design

Abstract

The design of structures using only elements available from a finite inventory, or “inventory-constrained structural design” (ICSD), presents a challenging design and optimisation problem which is not well addressed by conventional approaches. Improved ICSD techniques could enable significant life-cycle impact reductions in future construction through increased component reuse of elements from deconstructed structures, and increased use of minimally processed low-impact whole (round) timber elements. Such techniques could also enable more efficient utilisation of overstock structural elements and improved design in rural and developing regions with restricted structural material supply chains.

Conventional structural design methods are ill-suited for ICSD because they do not allow for the consideration of inventory constraints, and do not account for the impacts and costs associated with offcut waste. ICSD methods developed to date for whole-timber construction have been problem-specific and do not allow for simultaneous consideration of structural and inventory constraints. ICSD methods for steel component reuse developed to date may not execute quickly enough for use in early-stage structural design exploration, the project phase when the greatest reductions in life-cycle impact and improvements in performance of new structures are likely to be achieved. This thesis first presents novel analytical methods for simplified characterisation of the design space of a class of ICSD problems in early-stage design. Next a new metric is introduced for comparing the performance of inventory-constrained designs considering offcut waste. Finally, new computational methods for ICSD are presented which allow for rapid generation of efficient assignments of inventory elements to given structural topologies and geometries subject to inventory and structural constraints. These methods are shown to produce assignments approximating theoretical optima for a set of benchmark problems. The methods are also shown to produce solutions within time intervals known to be conducive to high productivity in creative interactive computer-aided tasks.

A design exploration procedure incorporating the above assignment optimisation methods is demonstrated for rapid discovery and refinement of high-performing inventory-constrained structural topologies and geometries. The methods presented allow designers to identify a range of feasible and high-performing inventory-constrained structural layouts in early-stage design exploration while flexibly accommodating non-structural considerations. The above methods are demonstrated for the design of trusses using whole timber and trusses using reclaimed steel elements. The thesis concludes with a discussion of potential extensions to the above approaches and their integration into structural engineering practice in future.

Date of Award	24 Jun 2020
Original language	English
Awarding Institution	University of Bath
Supervisor	Paul Shepherd (Supervisor), Pete Walker (Supervisor), Bhavna Sharma (Supervisor) & Julie Bregulla (Supervisor)