Inventory constrained design of a timber funicular structure

Abstract

This research investigates the development of a digital form finding model that combines the generation of funicular geometry with a material inventory constraint. The model provides a flexible design tool that facilitates exploration of structural form whilst simultaneously satisfying two rationalizing criteria. It maintains an equilibrated structure derived from funicular geometry; and optimises the assignment of a unique inventory of timber members having natural dimensional variation. The combined goal for the design outcome is to achieve material efficiency through both structurally rational form and minimization of material waste. The material chosen for the inventory is utility-grade sawn timber, being lightweight but with high levels of naturally occurring structural variability. Sawn timber boards that are rejected for structural applications due to frequent structural defects (knots, checks, splits etc.) represent up to 50% of the sawn product produced by Australian sawmills, and are destined for under-valued non-structural use, chipping or burning. Yet these boards can readily yield usable short length structural members, once defects are removed. In doing so, the process creates a unique inventory of random short members. These short members are well suited to articulated structures, which, by employing an inverted funicular geometry, only incur axial stresses and can employ simple (non-moment resisting) timber connections. This form finding tool and a first prototype pavilion are proofs of concept for viable structural application of what is otherwise a significant source of waste in the timber industry.

WoodN - In search of a constructive system for a sustainable temporary architecture

“…The potential of computational imaging for non-standard wood fabrication has been both discussed (by Mario Carpo and others) and demonstrated in built projects (at AA Hooke Park, University of Michigan, Aarhus, Bath and elsewhere) over the last several years. (Baber et al, 2020;Bukauskas et al, 2017;Brütting, Senatore and Fivet, 2021;Carpo, 2017;Devadass et al, 2016;Self and Vercruysse, 2017;Von Buelow, 2018;Larsen and Aagaard, 2019).…”

Stock-constrained truss design exploration through combinatorial equilibrium modeling

“…34 An adapted version of the method 34 has been successfully applied to build a funicular timber gridshell. 35 An extension to the method 34 allows consideration of displacement constraints and has been applied to small-scale examples. 36…”

“…4,6 As shown above, several methods to design structures based on an element stock are available. However, the existing methods 28–30,34,35 are mainly concerned with stocks of timber elements and not with reclaimed elements from obsolete buildings. Some methods 28,29,33,35 only focus on the geometric fitting of elements to pre-assigned target shapes, without considering structural limitations.…”

“…However, the existing methods 28–30,34,35 are mainly concerned with stocks of timber elements and not with reclaimed elements from obsolete buildings. Some methods 28,29,33,35 only focus on the geometric fitting of elements to pre-assigned target shapes, without considering structural limitations. Another crucial aspect, that so far has only been addressed by Brütting et al 37–39 is the quantification of environmental impacts to show whether reuse is beneficial compared to new element production.…”

Friction magazine: The upcycling of manufacture for structural design

“…8 Nowadays, the structural design strategies with reused elements usually referred to as stock-based design were explored. [9][10][11][12] A few proposals were developed in the field of structural upcycling using manufacture goods, 13 with a particular interest to skies. 14 Furthermore, construction methods with non-structural materials, such as plastic bottles or soda cans keeps gaining in interest, especially for temporary, artistic, or festive applications.…”