Researchers have been working to deliver and validate technologies that transform low-value forest resources and sub-optimum quality logs into high-value construction and aesthetic products suitable for Australian and international markets.
Findings have supported the successful development and commercialisation of veneer-based bridge girders.
A resource assessment study identified a substantial volume of under-utilised, small diameter logs within Australia’s native forest and hardwood plantations that could be available for conversion using new spindleless lathe technology. The approach may also have a secondary benefit, assisting improved silvicultural management.
When applied to these sub-optimum logs the spindleless veneering technology was shown to yield more acceptable recoveries compared to traditional sawing approaches. The resulting veneer contained qualities and properties well suited to the manufacture of veneer-based engineered wood products (EWPs).
Dr Robert McGavin, Research Facility and Project Manager at the Department of Agriculture and Fisheries’ Salisbury Research Facility, whose team led the research, said the project has provided a wealth of new knowledge for the Australian industry.
“It has identified many technical and economic opportunities for industry to consider, which utilise forest resources that are currently under valued, for the manufacture of high-performing, value-added engineered wood products,” Dr McGavin said.
Critical to the project design was direct participation and guidance by forest industry stakeholders.
“Active participation of key industry stakeholders throughout the project in parallel with the commercial investigations demonstrate strong industry interest,” Dr McGavin explained.
A comprehensive product and market assessment revealed the new ‘mid-rise timber’ construction sector provides significant opportunities for a wide range of structural and appearance timber products, both sawn and engineered.
Better performing structural EWPs may provide attractive opportunities for many of Australia’s high-strength hardwood species, due to the higher structural loads of taller buildings.
In addition, a reflection on traditional markets occupied by Australia’s native forest species identified potential for:
· veneer-based EWPs in electricity network cross arms;
· road and rail bridge components; and
· large dimension posts and beams.
The project steering committee also identified a number of likely ‘best bet’ products, taking into account the strengths and weaknesses of available timber feedstocks, outcomes of the forest assessments, results of the project processing studies and an understanding of potential products and markets. These ‘best bet’ product groups included laminated veneer lumber (LVL) based products and mass panels.
“The best chance for project output adoption would come from close partnership with industries ready to adopt and develop the necessary practices required to produce the new products,” Dr McGavin said.
Big River Group Case Study
One example of this type of collaboration in practice came when project industry partner, the Big River Group, pursued the development and commercialisation of veneer-based bridge girders.
This innovation was in recognition of industry and market feedback that replacements for traditional girders are becoming increasingly difficult to source. Coupled with growing demand for bridge components to maintain the many thousands of existing timber bridges in Australia, many girders are being replaced by concrete and other more expensive alternatives solutions due to a lack of supply.
The market intelligence of the Big River Group provided an initial design constraint of 450 mm girder beam depth, to ensure compatibility with common traditional girder dimensions. Therefore, an end-of-life traditional girder could be removed and replaced with a new veneer-based girder without significant disturbance.
The structural performance of a new girder also needed to be at least comparable to the traditional F22 and F27 hardwood girders. Predictability of performance, lightness of weight and the certification of structural properties were also viewed as attractive by the market.
An LVL-based design was developed, and prototypes were manufactured. Native forest hardwood veneers were combined with plantation softwood veneers to ensure strong performance while limiting the overall weight of the new girder. The prototypes were tested to determine key mechanical properties, validate design targets and facilitate engineering certification.
The Big River Group is now reporting the new veneer-based girder is around 22 per cent lighter, 35 per cent stronger and 5 per cent stiffer than a traditional F22 hardwood girder. To date, the company has manufactured and sold 150 of these new girders at a value exceeding $600,000, with seven bridges constructed using the new girder systems.
Market feedback has been incredibly positive and an increasing number of local governments are now considering the product as a viable option for maintaining their timber bridge networks, and for new bridge construction.
The Big River Group example demonstrates how reviewing the competitive advantages of Australia’s native timber species has been an effective means of steering the product development strategy for new, high performance EWPs.
“Some traditional markets held by the native forest industry demand the performances that are unique to Australia’s native timber species. However, it is becoming increasingly difficult for the native forest industry to meet demand, due to the general decline of log quality,” explained Dr McGavin.
“It makes sense to explore options to develop substitute EWP solutions using the same fundamental wood resource. This strategy has the potential to commercialise more new, high-performance EWPs.”
The full report can be found by clicking here.
