Interview with Ario Ceccotti 11 JUNE 2019
Working in Structural Stability, Wood Engineering, Seismic and Wood Structures, Ario Ceccotti taught at the IUAV University of Venice Department of Architecture, Construction and Conservation, and was director of the Forest and Wood Institute (IVALSA) at the National Research Council (CNR) in Italy. In the 2018-2019 academic year, Ceccotti started teaching as a Visiting Lecturer in the Department of Civil Engineering at Boğaziçi University. He answered our questions on forest products and wood.
How did you decide to turn to wood and especially wood structure in your academic work? Is wood engineering a common specialty in the world?
Ario Ceccotti: As a civil engineering student in the late 60s and also an avid reader of the Jean Dorst and Rachel Carson books, it was inevitable that I would respect the environment in my work in engineering practice in the future. Wood seemed to me at the time to be a must for an environmentally friendly construction industry. You cut down trees and they grow again with solar power; so it requires less energy than other building materials that could be used as renewable structure material, and also-this was not an issue under consideration at the time - Wood has the capacity to “hold” CO2, thereby contributing to the reduction of global warming.
The need to comply with the sustainable use protocols, which allow to cut down a certain amount of trees that grow each year, such as the FSC (Forest Conservation Council) or PEFC (Pan European Forest Certification) is the most important point here in the use of forests. In other words,”maintaining capital and using only a small amount of the annual interest." So the forests are processed correctly. Thanks to the commercial use of wood, it provides economic benefit to investors and brings value to investments. In this case, our motto is: “use wood to save forests.” Later, as a university researcher, I continued to work with structural wood, new tree-based materials such as CLT (multiplaz laminated wood), and conducted special studies on their seismic performance. The wood we knew in the past as a weak, quickly decaying and burning material has nothing to do with the wood we use today. Over the last three decades, very impressive studies has been put forward. Building designs in Europe and Turkey (may be unknown but TSE: Turkish Standards Institute, CEN: a member of the European Standardization Committee) are subject to the Eurocode - European Building Design Regulation. These codes set the standards of wood (Eurocode 5) as well as concrete (Eurocode 2) and steel (Eurocode 3) materials used in structures.
Wood Engineering is highly developed all over the world; national and international conferences are held every year (most notably WCTE: World Wood Engineering Conference, next one will be held in Chile in 2020); universities and research centers are increasingly focusing on wood engineering. There is a large area of research extending from material level to building level. Despite this, the wood researchers are still quite few compared to concrete and steel researchers.
Apart from its structural use, how do you see the use of wood on the floor, roof, facade as surface coating material and so on?
AC: The structural use of wood in today’s sense is quite new. The non-structural use of wood or wood-based materials such as flooring, ceilings and coating is much older. Whether or not to prefer wood to other materials is the subject of architectural design and the result of some decisions made by the designer. Is it possible to say that Wood is cheaper, or can we claim that it looks more beautiful? Is wood more environmentally friendly; is wood's sound absorption or resonance performance better? Do you feel better in a room with all its walls covered in wood, or can wood regulate the moisture in the room? All these points should be known to the designer and taken into consideration before final decisions are made.
Wood is often an expensive material in Turkey and it is quite difficult to find a good wood master. For this reason, tree-based products such as MDF are used in large-scale construction. Can you tell us about the structural properties of these materials and the environmental impact of the industrial forests used in their production?
AC: I think Turkey should take the time and budget to qualify its own wood according to international standards. You have a lot of forests and you have a huge responsibility to use them in a sustainable way. You can also create new tree nurseries with some fast-growing species. I don't see anything wrong with that, especially if you're going to develop marginal areas in your region. From pine to ladin and chestnut, your trees are made of solid wood as well as glued laminated wood or more up-to-date cross-laminated wood, which allows structural use.
But many laboratory tests are needed to certify their reliability by Cen standards. Once this is done, your tree can be sold not only in Turkey but also in the rest of the world and can make a big contribution to your economy. By these standards, the use of each piece of timber as a structural carrier will be guaranteed. Of course you need a management center to manage this whole process but in Turkey there is already a Ministry of Forestry, which supplies the wood, Forestry Faculties, which tests its performance, and civil engineers, who analyse the wood.
Mechanical properties of MDF (Medium Density Fiberboard) are listed in European product standards and conditions as one of the structurally usable tree-based materials. It is also possible to talk about some advantages of MDF. For example, compared to solid wood, the fire resistance of MDFs can be increased by adding resin and modifying its chemical components. In addition, MDF panels can be resistant to fungals or ants by adding suitable additives to the adhesive depending on the climate zone in which they are used. The timber we use today can be shaped at 1mm precision in factories thanks to today's CNC machines, leaving workers to mount only suitable parts on the land like a giant lego using long self tapping screws and mechanical coupling systems. At this point the Masters can be instructed quite simply and the renaissance of the wooden structure may be possible in Turkey. Your country's performance in the past centuries is one of the most advanced in the world: you have the largest wooden structures in Europe, such as the six-storey orphanage in Büyükada. Himis technique is also known as one of the highest level of earthquake resistance construction techniques.
What do you think about the use of wood in hybrid structural systems?
AC: These days, new tree-based products such as CLT, LVL (Laminated Veneer Lumber) push the boundaries of the wood structure. There seems to be a hidden race to build even higher wooden structures. One thing should not be forgotten: Wood is a material as durable as concrete. This is why you might consider building a skyscraper out of wood, but unfortunately the coefficient of elasticity of wood is as much as 1/3 of concrete, and this ability to change shape plays an important role in the design. Hybrid systems may be the solution at this point. Concrete-wood mixed structure can combine the rigidity of the concrete and the lightness of the wood. The Brock Commons building, located on the campus of the University of British Colombia in Vancouver, where the concrete core is wrapped in a wooden cage, is a good example of this.
How do you evaluate the current state of wood engineering education as a specialized academic in this field? Have you taught in architecture schools before, or have there been Architecture students who have taken lessons from you?
AC: Today, I think that we should reintroduce wood engineering to engineering faculties and that structural use of wood should be taught to engineering students. The most recent academic work on this subject belongs to Abdullah Turkmen of ITU in 1948, and there is not a single work that has been done since then.
I do not know the situation in architecture faculties in Turkey, but I think architecture students are more familiar with wood because they are always pushing their boundaries to carry their design to a new ground. During my teaching period in Venice, I witnessed the interest of architecture students in wood materials. They are always interested in the use of new materials or new forms of application of a familiar material but if we're not talking about a repetition of an existing building or a simple restoration project, how will they be able to offer a customer a new structure made entirely of wood without the support of Engineers?
In the chasing of the tree: “An Interview With Ario Ceccotti”, Arredamento Architecture, May 2019/331, P. 44-45.