As the knowledge and understanding of different timber species has grown, so too has the use of timber in applications where strength is a key performance criteria.
Timber's superior strength qualities provide a versatile and reliable building material for a wide range of structural applications - from beams, walls and flooring through to formwork and large timber panels. Backed by Australian Standards for design and construction, timber framed construction is tough and reliable. When combined with good design and detailing, it can withstand some of the most extreme weather conditions Australia has to offer.
Structurally graded solid timber, is a popular choice for framing material in Australia. Sawn timber, particularly in seasoned form, is highly valued in structural applications for its favourable strength-to-weight ratio, durability and dimensional stability. When used in large engineering construction, its strength performance is based on visual grading and the durability rating of the species. For domestic construction, mechanical grading is also utilised.
Density is the single biggest factor influencing the strength of a piece of timber and while solid timber hardwoods are indeed dense, timber density can be increased even further through the creation of engineered wood products. Engineered wood products have defined and standardised structural properties making their strength and stiffness characteristics measurable and reliable. With the latest advancements in computing technology and adhesives, engineered wood products offer a strong, reliable and cost effective solution for almost every structural application.
LVL, glulam and CLT are but some of the product choices available that offer superior strength performing properties.
LVL is manufactured by bonding together thin wood veneers under heat and pressure. Once glued together, these layered timber pieces create a very strong and durable timber member. These properties have shown to be similar to that of Australian produced hot rolled steel sections. A comparison with steel and concrete shows that Radiata Pine structural timber has a strength for weight ratio 20 per cent higher than structural steel and four to five times better than unreinforced concrete in compression.1
Glulam is simliar to LVL in strength, however it has a wider range of applications due to its architectural aesthetic. Glulam is manufactured from a large number of small pieces of timber, laminates, which are joined together to create large structural members. Glulam is most commonly used for beams. Massive glulam beams that are used for residential and commercial applications provide outstanding results in terms of design and application.
One of the latest engineered wood products on the market is CLT or cross-laminated timber. CLT has been described as 'giant plywood' and is made in much the same way - but on a larger scale. Large CLT panels offer the same strength as a concrete equivalent but are significantly lighter, creating obvious benefits.
While there is a plethora of buildings, both residential and commercial, that have been constructed out of pre-fabricated concrete panels, the reality is that CLT panels can now do the same job, albeit more efficiently.
To learn more about timber's strength performing properties and engineered wood products see the following links and reports available for download.
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Engineered Wood Products Association of Australasia (EWPAA) website www.ewp.asn.au
1 Build in Timber. Forest and Wood Products Research and Development Corporation 2005
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