By uniting research, regulation and guidance, Australia raised the bar on fastenings and connections across concrete and timber.
Boston’s Central Artery/Tunnel Project, known as the “Big Dig”, was the largest and most technically challenging highway project in US history. Built beneath the city’s historic core, it surpassed the Panama Canal, Hoover Dam and Alaska Pipeline in scale.
But on 10 July 2006, a portion of the Big Dig’s concrete ceiling assembly gave way, sending multi-ton panels onto the roadway and killing a motorist. Six years later, in Japan’s Sasago Tunnel, around 140 m of ceiling panels collapsed, crushing vehicles and igniting fires.
In both cases, the failure of seemingly minor components – fasteners – was at fault, said Associate Professor Jessey Lee, Deputy Chair of the Department of Civil and Construction Engineering at Swinburne University of Technology.
“Fasteners don’t get much attention,” she said. “But when they fail, people can be killed or injured.”
Creating a national fastener standard
Australia chose not to wait for its own wake-up call. In 2012, Swinburne convened the Australian Engineered Fasteners and Anchors Council (AEFAC) to bring fastening practice into a transparent, test-based, design-checked system referenced in the National Construction Code (NCC).
“At the time there were no deemed to satisfy Australian design standards for fastenings in concrete, so engineers relied on suppliers’ data that was hard to verify,” Lee said. “Products were coming from everywhere, tested to different standards – or none at all.”
Within three years, the industry had a technical specification cited by the NCC – Australian Standards Technical Specification TS 101; by 2018, a full Australian Standard replaced it.
“Getting a national regulation referenced within three years was unprecedented,” she said. “It set the rules for design, product testing, and installation expectations – addressing all three critical elements at once.”
Since then, AS 5216 was developed for concrete fastenings. Building on that success, AEFAC formed a timber fastening group to address similar issues in timber.
Clear pathways for timber fasteners
AEFAC’s Timber Fastening Technical Committee – supported by manufacturers and led by Swinburne researchers – has zeroed in on the weak link in many timber systems. The committee examines how the connections – such as brackets, nailplates and screws – that make floors, roofs and walls work are tested, evaluated and designed. The current test-method standard, AS 1649, was born in another era; industry now needs a transparent, repeatable pathway that aligns with limit state design and modern products, said Dr Anita Amirsardari, a Research Fellow at Swinburne University of Technology.
“The standard has been recently updated, however the methodology is dated to the 1970s, so it doesn’t suit today’s timber construction practice and contemporary engineering principles,” she said. “The design basis has shifted from working-stress to limit state methods, so the evaluation framework needs to match current practice – and we’re updating it for transparency and reliability.”
A Swinburne-authored review of Australian timber connection design – awarded Engineers Australia’s 2024 RW Chapman Medal – mapped the lineage of factors and methods required so the next iteration of the standard isn’t guesswork.
“The journal paper provided a historical overview of Australian connection design and clarified where certain factors in today’s standards came from,” Amirsardari said. “That gives us confidence to make changes when developing new provisions.”
Connections that deliver mid-rise performance
To meet sustainability goals and residential construction demand, Australia is procuring more mid-rise timber structures. But as buildings get taller, lateral actions and diaphragm behaviour dominate risk.
“Connection design becomes critical: you need accurate approaches that avoid both under- and over-design,” Amirsardari said.
Much of the currently cited diaphragm guidance traces back to overseas practice from decades ago and does not reflect Australian framing details or on-site realities.
Prefabricated wall and floor panels, diaphragms and modular sub-assemblies promise better tolerances, faster programs and less waste – but only if the connection details are robust, repeatable and installer-proof.
“Timber buildings up to eight storeys high are permitted by regulation, but as heights increase, loads such as wind become more important,” Lee said. “Floor and roof diaphragm design must reflect Australian construction practices, which current methods don’t fully suit. So AEFAC – driven by industry partners – is developing improved approaches.”
The committee is advancing design provisions for connections in mid-rise buildings, with a focus on floor and roof diaphragms that distribute wind and earthquake loads to vertical bracing systems, improving overall structural integrity.
While fastenings can seem small and inconsequential, they’re often the weakest link, Lee said.
“Everything is only as strong as its joints,” she said. “AEFAC exists to lift safety and standards across the industry… a unique, long-standing collaboration where university and industry competitors meet in a neutral forum to work for the good of the Australian construction industry.”
AEFAC Industry technical notes, FAQs and resources can be found here, with free online training on fastenings in concrete also available.
Information about Swinburne University of Technology’s Engineering degrees is available on their website.
The journal paper on “Review of timber connection design in Australia” can be found here.
