Rule-based Design Analysis and Structural Rationalization Study of Ralph Symonds Laminated Timber Arches

ABSTRACT

As the demand for steel increased to supply military construction during World War II, Australian engineers began to push timber capacity for long-span structures, one of which led to the emerging use of glue-laminated timber-bending in the post-war period. This article analyses the laminated timber arches of three Ralph Symonds factories in Sydney, the ground-breaking laminated timber projects in Australia between the 1940s and 1960s. The study interprets the design reasoning behind timber-arch application and the structural reasoning behind timber bending using daylight simulation, structural simulation, and rule-based design analysis. The method used to formulate the rules is outlined and demonstrated. The study clarifies that Symonds’s timber-arch designs evolved not only to accommodate space for medium to large-scale manufacturing activities but also to optimize economic, climatic, and structural constraints. The rule-based analysis reveals a consistent design logic applied across different factories, foregrounding Ralph Symonds’s signature design language in laminated-timber arches.

KEYWORDS:

• Arches
• factory design
• laminated timber
• Ralph Symonds

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

¹ The St Peters factory was demolished in May 2017 for the West Connex highway projects and a part of the arches were salvaged and are to be reused (Extent 2019).

² To the best of the author’s knowledge, this remaining part of the RS Homebush factory is not listed in the NSW State Heritage Inventory (Draft Block H Voluntary Planning Agreement for Exhibition 2020).

³ This cost analysis does not include factors that might affect the price, such as deals between RS and the roof cladding manufacturer for large procurement, or that RS might have adjusted his roof curvature to fit the most affordable curved-roof sheet available in the market at the time.

⁴ The initial barrel-roof structure in Alexandria also resulted in a lack of daylight and had non-usable space due to a low ceiling on its side. This was fixed with the addition of second rafters and ‘stepped windows’ on its side in 1946 (Nolan 1994, 145; Forestry Commission of NSW 1942).

⁵ Documentation on how RS bending machine works is not adequate. Some sources stated that the laminated timber was ‘compressed’ with ‘air rams’ (Stanley 1949, 26; Forestry Commission of NSW 1942, 50), another claimed that the machine ‘sucking the wood together instead of pressing’ the timber (Ralph Symonds Plywood 1953, 10). Nevertheless, it is possible that RS combined ‘continuous hydraulic presses’ and ‘radio-frequency curing’ in his method, rather than using clamping beds or on-site progressive clamping that could take longer period (Moody and Hernandez 1997, 1–11).

⁶ Beam analysis in Kangaroo3D provides elastic bending simulation before an object reaches its equilibrium state, where the timber behavior under different supports conditions and loads can be observed for a single material.

⁷ Nolan observation that states “The base pin to the arches was very simple. They were later made into fixed joints by welding plates top and bottom of the arch shoe” implies that RS might initially use pin-joints without welded plates at the beginning (Nolan 1994, 189).

⁸ Karamba3D simulates the final equilibrium state and can analyze multiple materials within one configuration, in this case, the timber beam, steel connector, and concrete base.