Following the success of Australia’s tallest fully timber residential tower, the Forté apartment complex in Melbourne’s Docklands by Lend Lease last year, comes that nation’s tallest timber commercial building. To be located on Sussex Street in Sydney’s central business district, the seven storey building is designed by Fitzpatrick + Partners and delivered by Lend Lease.
The timber-framed building will predominantly be constructed with glulam, or glued laminated timber.
Glulam is typically made from plantation softwoods such as Spruce in Austria, or Radiata Pine in Australia and New Zealand.
Allowing larger pieces of timber to be produced than otherwise possible with traditional solid sawn timber, glulam is stronger and lighter than solid timber, but comparable in strength to steel. The laminates are dressed to exact and uniform thickness before gluing, and are clamped together under constant pressure until the glue has dried.
The layers of glue help with the protection of the timber by creating barriers that prevent moisture.
After completion of its Forté building, Lend Lease indicated it intended to make greater use of cross-laminated timber (CLT) on its multi-residential projects.
In an address to an Australian Property Council industry event last year, company business manager for CLT-development Andrew Nieland described engineered timbers as being what the 21st century was all about and said use of CLT on Forté had cut construction time by up to four months, reduced projected CO2 emissions on the building by around 1,400 tonnes and most importantly, had delivered a cleaner and safer work site.
Frame Australia, organizer of the Prefab Timber and Engineered Wood in Building Construction Conference, says a trend toward increasing use of engineered timber products has taken hold in Europe and North America, according to SourceAble.net Wednesday. The trend started in Australia with the construction of the Forté apartment.
Frame Australia also notes that while pre-fabricated trusses and frames remain the most common timber building system, use of complete floor cassettes and panelized walls is growing.
CLT and Engineered Wood
The Fitzpatrick + Partners design is for a multi-storey, A-grade CBD office building entirely from timber. The firm has dedicated significant research and development to timber applications over the last few years, including visiting timber factories, construction sites and buildings around the world, said Architecture and Design Thursday.
For multistorey buildings, CLT construction solves the problems associated with conventional wood-frame construction. Individual CLT panels of single-storey height are assembled in a factory, providing computerized accuracy. Window and door openings are precut. Other units can be stacked and fastened on top of the first, allowing multiple storeys to be lifted into position with a crane.
CLT beams have strength comparable to steel. As for fire hazard, the interior panels are usually covered with a layer of fire-resistant gypsum. Materials resistant to flame may also cover the exterior wood surfaces. Cross-laminated timbers are reportedly safer in a fire than steel. Thick wood beams char on the outside, providing resistance to deeper burning, while extreme heat causes steel to bend and collapse.
Steel and concrete require far more energy to produce than wood and the production generates massive quantities of carbon dioxide – aka, greenhouse gas. While some carbon dioxide is created during logging and lumbering operations, a tree’s growth depends on and “absorbs” carbon dioxide from the air during its growth cycle.
CLT construction results in a lighter building and thus requires less concrete for a foundation. Other cost savings have added up to an average price reduction of about 15 percent. In addition to wood construction being environmentally friendlier than steel and concrete, it has far better insulating qualities than the other two, resulting in lower heating and cooling costs.
Still in Australia, a new plywood bridge deck system, branded Bridgeply, has been found for replacing about 30,000 timber bridges that are currently deemed unsafe.
Until now councils have been relying on steel or concrete alternatives to replace and repair their timber bridges, which come at a significantly increased cost, according to Info Link, also Thursday.
Launched recently by Australian timber specialist and major plywood manufacturer, Big River Group, Bridgeply is an engineered substitute for traditional hardwood decking. Bridgeply can effectively extend the safety, lifespan and capacity of ageing timber bridges with considerable cost saving and at a significantly reduced rate of construction.
Manufactured from sustainable timbers, Bridgeply plywood bridge deck systems serve as a replacement for bridge decking where suitable lengths of solid hardwood timber are not available. Maintaining a width of 1200mm, lengths and thicknesses can be made to meet specifications offering great flexibility in design. Particularly effective for smaller bridges, Bridgeply is cross-laminated to ensure even distribution of longitudinal and lateral stiffness.
Bridgeply plywood bridge deck systems are lighter in mass than concrete and steel and therefore easier to manoeuvre and use, and are compatible with a variety of support structures.
In America, the White House Rural Council in Washington, DC, promotes economic opportunity in rural America and, along with the US Department of Agriculture, issued a directive to 80 wood-products representatives to pursue sustainable building, research, advanced product manufacturing, and state and local policy initiatives to advance wood construction.
SmartLam, out of Columbia Falls, MT, is the only manufacturer of cross-laminated timber, or mass timber, in the US. The unique product was the centre of conversation at the workshop, but very few knew that the product is being manufactured in the US, said SmartLam general manager Casey Malmquist to the Hungry Horse News May 2. Europe has been the leader in cross-laminated timber manufacturing.
SmartLam began producing the engineered wood product at the Western Building Center site in Columbia Falls last year. The company found an immediate niche in mats for heavy equipment in North Dakota and Texas oil fields. But a big drawback as a “first generation” plant is that manufacturing is largely done by hand, Malmquist said.
The plant currently produces 100,000 board-feet of mass timber each month, but the addition of another lamination press and a 12-ton computer numerical control machine will double production.
Malmquist’s construction company has been busy in the Bakken oil patch, building 56 homes, 44 townhouses and two 24-unit apartment complexes in Williston, ND.