Timber Building in Australia

A review of timber engineering conference proceedings since 1989, a total of nine hundred and forty-five papers, reflects a gap between engineering technical research aspirations in timber and the transfer of this information to a wider audience. In addition, the direction of timber engineering research does not appear to be strategically driven by concepts that relate to a 'big picture' of possible futures. There are researchers in forty-six countries publishing detailed and challenging papers that form the primary 'jig-saw' pieces that together could produce a comprehensive picture. However, as they tend to work in small isolated groups setting their own agendas, meeting every two years, the linking of these pieces to produce a comprehensible body of knowledge that clearly informs and shows the relationship of the pieces is missing. This gap - the failure in communication - has to be redressed. We need more evangelical and articulate timber engineering design researchers with a gift for communicating and enthusing the timber industry, client bodies, the design professions and students with their work. Whilst this is lacking, the participants in the potential dialogue lack a common language in which they can fruitfully agree or disagree - a condition which will continue to frustrate all who wish to see greater change and progress in the use of engineered timber.

Keywords: architect engineer design future research trends education innovative timber structures communication.

"The Tragedy of the world is that those who are imaginative have but little experience, and those who are experienced have feeble imaginations. Fools act on imagination without experience. Pedants act on knowledge without imagination... "

Alfred North Whitehead

The relationship of architects and engineers is one which historically has produced an 'information gap' resulting in a great deal of lost opportunities for both professions. This gap has to be closed if

we are to progress in the application of timber engineering in architectural design thinking. A dialogue must be established whereby engineering research endeavor is informed by applied-design based needs of architects and vice-versa.

However, there are fundamental reasons for the historic development of this gap. The majority of students and staff are attracted to study architecture as art and tend not to be interested in the empirical design detail and the detailed resolution of structural problems. Architecture students also tend to explore radical new solutions to solve architectural design problems; solutions based more upon intuition than research and fundamental principles.

Mario Salvadori, an engineer who teaches both architectural and engineering students, provides a telling insight into the character of individuals attracted to study in the fields of Architecture and Engineering.

"Young People inclined to become engineers are, by their mental make-up and previous education, ........ willing to accept the dictates of science and to apply them to the practical problems of culture......

By contrast, those who decide to enter an architectural career are more open-minded, adventurous critically curious and independent. They chose architecture because they are interested less in the practicalities of life and more in the infinitely varied and complex problems of their society. "

Salvadori also suggests that the influence of professional education increases the tendencies that students bring with them when they chose a career: " ... engineering students are trained almost from the start to be specialists... Moreover engineering students are exposed to axioms: axioms cannot be challenged (except by geniuses), and the average engineering student learns not to challenge. "

.... (architectural students) are trained not as specialists but as generalists,........ Architectural students challenge their critics, are proud of their own architectural conceptions, and often believe they can challenge the world. Long years of practice will slowly diminish but seldom kill this attitude. "

These differences are largely manifest in the desire by architects to start with a clean slate and produce the innovative and unique solution (the 'worlds first'), and by engineers who are ecstatic if they can move the body of knowledge forward by the smallest addition of a piece of information that contributes to an understanding of phenomena.

The variation in mind sets in the design approach to problem solving is described very clearly in the classic book 'Zen and the Art of Motorcycle Maintenance'. An explanation of why these attitudes have emerged is the fundamental philosophical differences between what Pirsig describes as classical and romantic thinkers.

"The romantic mode is primarily inspirational, imaginative, creative, intuitive. Feelings rather than facts predominate. 'Art' when it is opposed to 'Science' is often romantic. It does not proceed by reason or by laws. It proceeds by feeling, intuition and aesthetic conscience. The classic mode, by contrast, proceeds by reason and by laws - which are themselves underlying forms of thought and behaviour. To a romantic this classic mode often appears dull, awkward and ugly, like mechanical maintenance itself. Everything is in terms of pieces and parts and components and relationships. Nothing is figured out until it's run through the computer a dozen times. Everything's got to be measured and proved. Oppressive. Heavy. Endlessly grey. The death force. Within the classic mode, however, the romantic has some appearances of his own. Frivolous, irrational, erratic, untrustworthy, interested primarily in pleasure-seeking. Shallow. Of no substance. Often a parasite who cannot or will not carry his own weight. A real drag on society. By now these battle lines should sound a little familiar. "

This is the source of the trouble. Persons tend to think and feel exclusively in one mode or the other and in doing so tend to misunderstand and underestimate what the other mode is all about.

Architectural design research has always been based upon a combination of traditional methodological research and speculative holistic design research. It is worth noting that even in the pure science, as a result of the changing paradigm of certainty [Chaos Theory], researchers have been given the courage to propose speculative holistic research. The test for a speculative research position lies in the outcomes, not in the eloquence of the argument. When such speculation results in an object or product then the reality of the design can be fully tested by the more traditional scientific methods. Design research speculation cannot be finite in its findings. The aim is to suggest that from the current base of knowledge and existing use a broader potential range outcomes are possible. This is research that asks of the cooperating partners 'what if?'.

A primary aim of the forest products industry appears to try to produce engineered timber that can substitute for old growth timbers in conventional building applications. The evidence in the conference proceedings suggests the application of these various research endeavors to the design of innovative comprehensive building systems is limited, for example research into rational structural forms in timber. Where are the cutting edge timber engineering research findings leading us? Are we going round in circles, preaching to the converted? If we do not know where we are going every step is a step in the right direction!!

Over the last six years there has been five international timber engineering conferences and nine hundred and forty-five papers have been presented by representatives from forty-five countries:

USA 229; Australia 111; Japan 110; New Zealand; Canada 58; Sweden 42; UK 38; Germany 30; Netherlands 26; Brazil 23; Switzerland 21; Finland 20; France 19; Malaysia 15; Denmark 13; Norway 12; Czechoslovakia 10; Austria 4; Chile 3; China 3; Croatia 3; Egypt 1; Estonia 1; Ghana 1; Greece 3; India 4; Indonesia 1; Israel 2; Italy 6; Korea 3; Macedonia 1; Mexico 6; Nigeria 1; Poland 7; Portugal 6 ; Slovakia 1; Slovenia 2; South Africa 8; Sri Lanka 1; Taiwan 2; Thailand 2; USSR 8; Zimbabwe 3; Country of origin unknown 6;

These five major international timber conferences were: International Timber Engineering Conference Tokyo Japan 1990; International Timber Engineering Conference London England 1991; 2nd CIB/W18B International Conference on Tropical and Hardwood Timber Structures Kuala Lumpur 1993; Pacific Timber Engineering Conference, Gold Coast, Australia, 1994, International Wood Engineering Conference New Orleans 1996. Fig 1 indicates the top eighteen countries measured by number of papers by country.

Figure 1 Countries who have presented more than ten papers at International Timber Engineering Conferences 1989-1996

A review of key words in the conference paper titles indicates the main areas of timber engineering research interest over the last six years:

Joints 82; load 76; laminated 59; construction 58; connector/connection 58; Behaviour 55; beam 52; stress 48; truss 46; composite 41; properties 40; fire 38; shear 36; performance 34; reinforced 27; creep 26; houses 26; nail 25.

Out of the nine hundred and forty five papers the word "innovation' appears seven times in paper titles, and it is interesting to note that four of these papers are to be presented at the 1996 IWEC. Exploring Innovative Timber Technology from an Architectural Approach, Stephanie Smith +1, Australia; Innovative Spatial Structures, Tom Williamson, USA; Innovative Design with Pre-Stressed Timber Joints, Ad. J. M. Leijten + 1, Netherlands; Innovations in Timber Engineering: The Hetzer Method, Wolfgang Rug, Germany.

Smaller numbers of papers have been presented on key areas related to the future of engineered timber use in the future:

moisture 9; education 7; architect 7; building design 6; details 4. Only one paper discuss the relationship of forest resources and the need for the world to be more sensitive to designing for a sustainable world.

There are fourteen papers which examine timber systems design. This requires the development of analytical tools and procedures for determining connections and interaction between covering and structural elements of walls, floors and roofs. The potential of such design methods, when incorporated with the new reliability methods is that it should improve the economy and flexibility of wood structures. Computer use in design coupled with system interaction analysis techniques will provide exciting opportunities to the design community. Work under way to tie the interaction between the wall, floor and roof systems together will eventually improve the design of the entire structure.

The gap between the timber producers and the users of wood is a very real problem. The timber industry consist of a small number of very large companies and thousands of small producers. The history and development of the timber industry from the earliest days, the education process of learning on the job, all contribute to a workforce and management that is conservative and resistant to change.

From an Australian perspective there is internal competition between the various sectors of the industry, and from overseas timber producers, in addition to external competition from alternative products. The timber industry sells wood as a commodity, with little research and development being undertaken in the exploration of new end uses for timber. The commercial limitations and disparate nature of timber production tend not to foster innovation.

Timber, like any other building material, is only as good as the people using it. If they're skilled, knowledgeable, imaginative and far-sighted, they'll be constantly finding new, more efficient and more cost-effective uses for it - uses which will help to boost its market position against competitors such as steel and concrete. If, by contrast, they are unadventurous, limited to familiar methods, they may even contribute to its decline.

Accepted techniques of milling, drying, marketing and forestry were born in the days when a ready supply of massive, well-grown, fully mature trees was available for processing to suit an equally ready market. A number of those techniques are being overhauled for today's era of younger, smaller, less 'perfect' trees. Changes in the forest and at the mill which might include greater emphasis on thinnings, short lengths, minor species, small sections and 'defective wood', all of which require an incentive in the form of new end uses.

In many areas of the world, plantation timber farming has tended to replace slowly maturing hardwoods with fast-growing conifers. And, as industrial methods and technology are used increasingly throughout the lumber industry, individual trees are much less likely to be selected for special, select purposes. Instead, logs are sawn in mills to standard sizes and sold without regard to their ultimate use. A pressing need is for the timber industry to educate designers to become more aware of the changing nature of the timber resource.

A challenge for all architects and engineers interested in timber design is to contribute to a much needed paradigm shift within the timber industry which currently sees itself as a resource-based commodity provider, primarily interested in manufacturing sticks or boards. The move to a more pro-active role in the promotion of 'down-stream' research and development in timber construction in building would increase the status of wood as material, and challenge the dominance of the steel and cement masonry industries in the non-domestic sector.

The exploration of new timber building forms; to utilise the changing timber resource of shorts lengths or composite materials; joint connections of epoxy resin and innovative mechanical connection, are all challenges yet to be fully explored. Design concepts are emerging in which the idea of recycling the product is not only a market driven opportunity but also a potential generator of form to allow for the logical dismantling and re-use of wood products in future building.

The need to understand behaviour is of great importance for all structural materials and, particularly, timber. Without an understanding of connection behaviour, and an appreciation of the unique qualities of timber as a material, it is very difficult for a designer to achieve creative expression and form in structural timber successfully as an architectural element. The curriculum of many courses in both engineering and architecture provides inadequate teaching of the basics of timber design and engineering. The European Union Structural Timber Engineering Programme [Timber Engineering STEP 1 and 2] programme is a very useful addition to the literature

The understanding of timber connections, their design and behaviour, are the most important design issues facing architects in the use of timber. There are many research programs being undertaken which represent many millions of dollars of timber industry and government funding throughout the world, and this information must be readily available if the future of timber engineering in architectural design is to be developed.

Wood is a organic hygroscopic material which requires good detailing for maximum serviceability. Wood construction offers flexibility and, in conjunction with proper building techniques, long term durability. Examples of many old wood structures in a wide variety of climates provide the evidence to support this claim. Design detailing requires special consideration be given to ventilation, thermal gradients and vapour barriers - aspects of design that impact on any construction material. Even simple information on this most basic requirement for timber designing is a largely 'lost' and requires rediscovery, documentation and promotion.

Most architects feel a responsibility to the environment far beyond the building they are currently designing. Unfortunately, the impact of some design decisions is more visible and more easily understood than others.

In a recent survey of building specifiers, the majority perceived wood to be the most environmentally friendly building material. This is due mainly to the renewability of wood, the low energy consumption required for production and the low levels of pollutant emission during manufacture compared to other major building materials.

In recent years, environmental considerations have acquired more importance in the specification of materials. Technical and economic aspects of building materials are still the primary considerations for specifiers, but increasingly, they are considering the environmental effects when selecting appropriate building materials for their designs. Architects, engineers and designers require accurate information to assess the true environmental consequences of the materials they specify.

The late engineer Ted Happold and colleagues have been associated with two innovative timber projects which reflect a bridging of the gap between architectural design aspirations and timber engineering innovation. The following brief details indicate innovative design processes that have led to unique timber building.

Timber Lattice Grid Shell

Mannheim Multihall 1975

The Mannheim Multihall was built for the German Federal Garden Exhibition in 1975. The design team was architect Carlfried Mutschel and Partners' with consultant and form finding of the gridshell by Atelier Warmbronn, Frei Otto and Ewald Bubner; Static calculation of the grid shell, Ove Arup and Partners by their specialist group known as Structures 3, Ted Happold and Ian Liddel with Michael Dickson.

This building is a unique inspiration in the potential of timber as a high performance material and demonstrated design technologies and building skills of the highest order. The organic form of the building raises in number of questions in conceptual design logic as the structural load paths results in very high stress areas in a number of locations. The manufacturer of the grid shell by Wilhelm Poppensieker GmbH reflects a knowledge of timber carpentry that indicates that the skill levels of craftsmanship are still available to introduce new technologies in timber.

The building uses 72 kilometres of 50 mm by 50 mm Canadian hemlock timber bolted together in four layer lattice grid. The timber grid shell covers 4700 m2 area. The spatially curved surfaces of the main hall span 60 m and are composed of square timber elements on a 500 x 500 mm grid. The struts are 50 x 50 mm in two to four layers. Curvature of the shell causes each square to become rhombus with angles 70 to 110°. Load is transferred at joints through friction between struts by using bolts and up to three disc springs and washers to increase pressure. The shape of the shell is such that a uniform vertical load causes only compression. Unsymmetrical snow and wind loads are absorbed through bending stiffness of the multi layered grids and tension cables that run diagonally to the grid.

A detailed account of the design methods and the construction process can be found on the Institute of Lightweight Structures publication IL 13 and more technical structural information on the timber lattice grid shell roof.

This building was constructed nearly 20 years ago and the massive scale and innovative structural system in timber still provides inspiration to all designers who visit the building. The building raises a number of issues in the logical use of wood and the construction skills required to construct it but the message is clear: with design skill and construction expertise, timber can used as a high technology construction material in a composite grid form.

Mannheim Multihall Fig. 1. Mannheim Multihall 1975

Fig. 2. Hooke Park - Student House under construction

Hooke Park

round poles forestry thinnings

This is a potentially revolutionary experiment in the use of green softwood forestry thinnings for making buildings at Hooke Park for John Makepeace in collaboration with Richard Burton of Ahrends Burton Koralek [ABK], and later with Edward Cullinan Architects.

The series of experimental timber buildings at Hooke Park, Dorset in the UK, were begun in 1985 and work is continuing. An underlying concept in this experiment was to add value to round wood forest thinnings and is a practical experiment on a 'developed' economy using waste wood. This experiment has achieved a number of objectives:

- by giving adding value to a waste wood product by design;

- by providing a commercial return for forest thinning;

- by providing this incentive to thin improving the remaining wood resource, and

- by reducing burn-off reducing carbon dioxide levels.

A prototype house and 600 square metre workshop training centre has been built at Hooke Park and occupied. A student residential building was under construction in November 1995. The primary design problem was to use waste green roundwood forest thinning as a material for structural applications and this was achieved by the use of innovative jointing technology and non-traditional design forms.

The experiments link all the activities needed to produce buildings and their constituent elements. The buildings are constructed from locally available tree thinnings and so all the activities from growing the trees, through felling, preparing and erecting the elements, are examined in the design.

In the case of Hooke park the trees were Norwegian Spruce. The nominal timber sizes were 50 to 150 mm in diameter and 6. 5 m long; in addition there were some larger sizes up to 11 m with a maximum diameter of 250 mm.

The most efficient way to use thinnings is in the round to maximise the natural strength it has as a tree and then use it tension or direct line compression. Using round components has meant a new approach to jointing, and using the flexibility of the spruce poles as a characteristic of the structure. The rafters will flex up to 200 mm at the centre of their span, and another 100-150 mm under a snow load.

A new high efficiency joint was developed to join 50 to 150 mm unseasoned roundwood in tension, this challenge produced innovation. The jointing system used threaded steel rods with eyes, set in a stepped conical hole drilled in the pole-ends. Embedded in the epoxy resin, this permitted connections to be made to the next piece of timber via the steel eye. An additional benefit of this joint is the avoidance of a metal to timber joint a common area of building failure.

The same joint system was used in the compression joints as the resin plug helps bind the centre fibres of the roundwood and avoid splitting apart under pressure. The joints were tested at the University of Bath School of Architectural Engineering before production on site. The strength transference between the steel and the wood allowed the joints to be used in both compression and tension.

The prototype house is designed with a series of central A frames supporting a ridge cable from which the thinnings are hung to form the rafters. At the eaves the rafters are fixed to what is the tension component a bow string truss. The horizontal timber member at the eaves is the compression member. The remaining timber members are all compression members acting to resolve the forces caused by hanging the roof members in tension. The walls lean in to resolve these forces, with the added benefit of an appropriate timber detail in protecting the face of the wall from water, as the best form of timber preservation is preventing it from getting wet.

Jointing System Fig. 3. Jointing System Hooke Park House

Fig. 4. Hooke Park Workshop

A conclusion the design and construction team reached in building this house prototype was in the specification and definition of material size and quantities. The range of sizes requires careful evaluation if the most efficient use of the resource is to be made.

The second experiment at Hooke park was the workshops. Using the experience gained from the prototype house the aim of this project was to explore and exploit further the characteristics of wet roundwood construction in an arch form and to build a clear span of 15 m with a working height of headroom along its edges. The building is 42 m long and 15 m wide formed by a central symmetrical shell and two asymmetrically end shells on either side linked together by two interstitial zones.

Boron salt preservation is used to protect the wood and advanced computer analysis enables efficient thorough complex three-dimensional forms analysis and cladding patterns to be produced for the flexible membranes, ensuring minimum wastage. In determining the form of the roof construction, the principle of the design of the workshop was that it should be constructed using pairs of freshly cut green roundwood timbers bent to form fixed base arches. The final design chosen was "a lapped design", in which the two principle arch members were connected together by a third element, known as a crown splice.

The advantage of this system was that a variety of spans could be constructed by adjusting the central splice without putting unrealistic demands on the thinning sizes. The arches when bent to the required shape and location [which was determined by computer analysis] were covered with two skins of PVC coated polymer membrane with a semi-rigid layer of insulation in between.

The demonstration of design approaches and application of technology is what makes Hooke Park as relevant to developing the waste forestry reserves of Australia as it is to the enhancement of British woodlands. High quality structures can be made from low grade material. The whole complex at Hooke Park is a continuous research centre in the use of wood by the students who use the facilities and new techniques and ideas are being explored. Davis 1970 "Hooke may be the start of a revolution in timber cultivation which will have incalculable beneficial consequences. "

"The long lead times which intervene between the emergent need for action and its achievement are partly due to the delays inherent in the processes of generating a sufficiently agreed view of the situation, a sufficient consensus on the course to pursue, and sufficient action to achieve it; and all these are collective processes, mediated by communication. " Geoffrey Vickers

If engineered wood products are to achieve their potential, Williamson argues that the industry should begin to attack the misperceptions of wood construction held by designers, contractors, building officials and owners by undertaking the following activities:

� Extensive education of designers, both current and future [universities]

� Extensive education of contractors, building officials and owners by emphasising its structural reliability, cost competitiveness and durability

� Instil confidence in the use of wood products

� Develop literature that accentuate the "positives" of wood construction versus the "negatives"

� Simplify the specification process for wood structures

� Develop simplified and user-friendly design aids for engineered wood product systems

A challenge is to contribute to a much needed paradigm shift within the timber industry which currently sees itself as a resource-based commodity provider, primarily interested in manufacturing sticks or boards. The move to a more pro-active role in the promotion of 'up-stream' research and development in timber construction in building would increase the status of wood as a material, and challenge the dominance of the steel and cement masonry industries.

In a Greenpeace internet document the "Environmental Guidelines of the Sydney Olympic 2000 Bid" support is given to the widespread use of timber with a requirement that all timber used in Olympic facilities be obtained from "sustainably managed sources". The report concludes that introduction of a credible system of timber certification has the potential to enhance significantly the competitiveness of Australian timber suppliers in the growing market for environmentally preferred products. The 2000 Olympics is an ideal opportunity to facilitate the introduction of such a system.

If timber is specified intelligently and efficiently in long life, highly valued and well designed applications then the potential for sustainable technologies to develop is likely to be greater than if the material is wasted in short life span, low value or poorly designed applications. Unfortunately, this is the case in many uses of structural timber in building today.

Timber has the potential to be environmentally and socially acceptable as the 'new' ecological and friendly building material for the 21st century. However this requires greater communication and coordination from the timber industry, design engineers and architects to promote best practice timber applications bench-marked against international experience. It also requires the development of the big picture within which we can all work, and leadership at the global and local level to harness energies towards a common goal. How this may be achieved is the problem.

Burton, R. , Moorwood, W. , Wilder, A. 1990. Fruits of the Forest, p. 12-13, Building Design Supplement, London, June,

Davey, P. 1990. Forestry Commission, The Architectural Review p. 44-48, London, September

Geottz, K-H; Hoor, D; Moehler, K; Natterer, J. 1989. Timber Design & Construction Source book, p 165, McGraw Hill, New York.

http://www. sofcom. com. au/Greenpeace/Syd Olympics 1990

IL 13 1978. Multihalle Mannheim, Freunde und Forderer der Leichtbauforschung, Stuggart

Pattern 8, 1991. Hooke Park College - house and training centre in green roundwood, Buro Happold Consulting Engineers, Bath September: 31-40

Pirsig, R. M. 1974. Zen and the Art of Motorcycle Maintenance - An Inquiry into Values; The Bodley Head, London p76-77.

Procedings of the

� 1990 International Timber Engineering Conference, vol 1-3, Tokyo Japan.

� 1991 International Timber Engineering Conference, London UK. Vol 1-4

� 1992 2nd CIB/W18B International Conference on Tropical and Hardwood Timber Sructures, Kuala Lumpur Malaysia.

� 1994 Pacific Timber Engineering Conference,. Conference Proceedings vol 1-2, , Brisbane Australia.

Program of the:

1996 International Wood Engineering Conference, New Orleans USA.

Salvadori, M. 1989. Bridging the Gap - Rethinking the Relationship of Architect and Engineer; Van Nostrand, New York.

Vickers, G. 1970. Value Systems and Social Process, Penguin Books, London

Williamson, T. G. 1993. Marketing engineered wood products to design professionals, Proceedings 47329 Wood Products for Engineered: Issues Affecting Growth and Acceptance of Engineered Wood Products, Forest Products Society, Wisconsin, p. 145.

Savage, D. , 1986. The gleaning of the forests, Woodworker, March p. 236-239.

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