Timber: trends in availability, sustainability and durability

Mick Stephens, Chief Executive, Timber Queensland

9th Australian Small Bridges Conference Gold Coast, April 2019

Jimmy's Gully Pedestrian Bridge, HarlinQld, Timber Restoration Systems

Mega-trends for timber bridges (+)

• wood availability

• innovation

• environmental recognition

• global certification

• cost-effectiveness and durability

• Wood Encouragement Policies

• health benefits

• renewable

• carbon-friendly

• innovative

• versatile

• cost-effective

Changing perceptions:

timber can be the solution

when it comes to bridges

Demand for timber

Product 2012-13 2029-30 2049-50

Sawn timber (Mm3) 5.1 6.0 6.5

Wood based panels (Mm3) 1.7 3.1 4.3

Paper (Mt) 3.6 5.8 7.1

Source: ABARES

Long-term consumption forecasts: Australia

Queensland consumption trends (previous 10 year average to 2013)

Product Consumption Production Imports

Sawn timber (m3) 1,200,000 850,000 350,000

• consumption projected to be stable to 2024 (BIS Shrapnel 2015)

• population and building growth will drive long-term demand

• mature industry

• able to respond to market needs

Wood availability: plantation regions

Wood availability: harvest levels

Source: ABARES

• proportion of harvest is exported as log or woodchip (7.3 Mt)

• balance made up of imported timber products (~2M m3)

Production 2016-17

Sawn timber 4.6 Mm3

Paper 3.2 Mt

Panels / EWPs 1.7 Mm3

Total log 33M m3

Native HW 4 Mm3

Plantation HW 11 Mm3

Plantation SW 17 Mm3

Area

Plantations 1.97 Mha

Native forest 36 Mha

Source: ABARES. Commercial native forest area where harvesting permitted.

Growth policy• Australian Government announced $20m

Forest Industries Plan in 2019

• aim to plant 1 billion new timber production trees by 2030

• R&D into productivity of existing plantations as well as new plantings

• increase domestic supply over medium term

• large potential to increase hardwood supply from PNF (e.g. Queensland, northern NSW)

• sawlogs + thinnings(smaller diameter logs) for solid girders, poles and EWPs

• > +100,000 m3 extra sawlog per year

• 1.8 Mha with commercial potential

Additional sawlog volume from improved PNF

silviculture & extension (South-East Queensland)

Private native forestry

Source: Venn & Francis (unpublished, QDAF/FWPA supported project)

Innovation: engineered timber

Cross Laminated Timber Laminated Veneer Lumber Glulam

Plywood

Innovation: wood processing advances

• improve recovery and value for EWPs

• rotary-veneer produced from low quality / smaller diameter logs

• application for new timber products

• lower cost processing technologies

Source: QDAF

Spindleless lathe & composite products, QDAF research laboratory, Salisbury

Innovation: tall buildings

• 25 King Street, Lendlease, Brisbane

• Tallest timber office building in Australia

• 9 storeys

• parallels with bridges

• growing global use of EWPs in tall buildings

• changes in regulations and codes for these products (UK, USA, Europe, Canada, Australia)

• strength, straightness and stability

• supplement solid timbers for girders, decks

• EWPs have same potential in bridge construction as for tall buildings

DiversificationSplinter Creek, South Burnett Qld, NiuBridge Systems

Forest sustainability: certification

• total area certified is 8.8 Mha

• Chain of Custody certificates = 189 (PEFC) and 258 (FSC)

Cumulative global forest area managed under major certification schemes

Source: UNECE / FAO (2016)

• 30% of world roundwood from certified forests

• increased 30-fold since 2000

Relatively easy to source certified timber products

Australia

Environmental benefits

Although some CO2 is released during the sawing and milling of timber, the net effect is that 8.3kg of CO2 is absorbed during both the growth and production of timber

Source: “Which is Better? Steel, Concrete or Wood”; Glover. J., Sydney University, 2001

GHG impacts: construction sector

Source: Yu et al (2017). The carbon footprint of Australia’s construction sector.

• construction makes up 18% of Australia’s carbon footprint

• 90.4 Mt in 2013 (499 Mt for Australia economy-wide), roads and bridges 9Mt

40%

21%

8%

31%

Embodied GHG from construction

Electricity

Materials

Construction

Other

Cement, concrete & brick were 39% of materials carbon footprint

Construction services includes concreting, demolition etc.

GHG impacts: timber benefits

• replacement of reinforced concrete with CLT in buildings generates lowest CF particularly when sequestration included

• what about bridges?

Source: Teh et al (2017). Replacement scenarios for construction materials based on economy-wide hybrid LCA.

• modelled GHG reduction for Australian construction

• switch to RE

• replace concrete with CLT or geopolymer at 2.4% pa

Emissions savings: bridge case study (Norway)

Both used stress laminated timber (SLT) decks and met load demand

• Case 1: 31% less emissions (1410 versus 2032 tonnes CO2e)

• Case 2: 35% less emissions (saved 13 tonnes CO2e)

Source: Gustafsson & Hagman (2017). Comparable life cycle assessment of concrete and timber road bridge desk designs. Conference Proceedings ICTB.

Case 1: Oppstadaa bridge. New timber arch and deck for large highway bridge, 120m span and 21m width.

Case 2: Vippa bridge. Concrete arch with concrete deck and steel beams. Replacement of degraded deck, 50m span and 6m width.

Durability and service life

• AS1604 well-established hazard classes

• fit-for-purpose

• service live depends on treatment, location and use

• 25 to >100 years

Source: FWPA Timber Service Life Design

Durability and service life • timber bridge service life can be extended through regular maintenance

• good design will reduce risk (e.g. water ingress)

• ease of replacement and/or repair well suited to short or long term needs

Source: FWPA Timber Service Life Design. Same principles for bridges.

Under deck connections, TRS

Versatility

• suits prefabrication

• modular

• light, transportable

• fast installation

• easily replaceable and/or repaired

Cowra Bridge, HQPlantations, Qld

Single lane bridge preassembled, TRS

Cost-effectiveness

• around 40,000 timber bridges across Australia

• proven case-studies of effective repair and/or replacement with timber

products and good design

• Cassowary Coast LGA replacement program ($ savings)

• numerous examples across Australia

Rakaia Gorge NZ

PNGFP NiuBridgeSystems

Mackay bridge (TRS)

Boundary Road bridge, Qld (TRS)

Boundary Road bridge, Qld (TRS)

Emu Creek, Niu bridge systems

Monash University student accommodation, Frankston (Multiplex)

CLT constructionSix levels, 150 unitsNet zero carbon strategy

• CLT construction

• Six levels, 150 units

• Carbon neutral strategy (private sector)

JUST COMPLETED

March 2019

Health

benefits

• researchers

• architects

• designers

• builders

• planners

• community

• bridges play an important role in urban and rural biophilic design (e.g. road, pedestrian, rail etc.)

Bridges: why wood?• renewable

• sequesters + stores carbon

• low embodied energy

• strong, light weight, fast

• cost-effective

• WEPs & sustainability policies

• biophilic benefits

• these trends need to be considered in the market

GBCA Green Leader of the Year. Source: Timber enews.

Adam Jones, Structural Engineer, TPC Solutions