Can wood be used as a major component in the new government buildings in Oslo? This was the topic of a Parliament hearing last month. Director Magnus Langseth from SFI CASA at NTNU was summoned.
The terrorist bomb blast in Oslo on 22 July 2011 killed eight and wounded more than 200. It also caused massive material damage. Several government buildings were rendered useless, some beyond repair.
As a consequence, new buildings are being planned. The ambition is to gather almost all ministries in a cluster in the centre of the capital. A winner of the architecture competition was announced last October. Projecting costs are expected to reach NOK one billion alone.
The sheer dimensions of the complex raise all kinds of questions, including how to display Norwegian industries and building traditions, opportunities for developing new skills and products, and environment friendliness.
All these elements have motivated a motion from four of the opposition parties to make wood a major component in the new buildings. This was the background for the open hearing.
After presenting himself, Professor Langseth went straight to the issue of dimensioning structures subjected to extreme loads.
“As far as wood, steel, concrete and aluminium is concerned, we have standards describing how structures should be dimensioned to tackle snow, wind and payload. However, there are no such standards for impact, penetration and blasts, with the exception for military installations,” he stated.
In spite of this, concrete, steel and aluminium is widely used in protective structures. This is possible because of the extensive research that has been carried out on these materials to understand how structural elements, connections and systems behave and therefore should be dimensioned. Such knowledge is scarce when it comes to wood.
Professor Langseth pointed to the importance of the deformation capacities of a material and the ability of a structure to redistribute forces. If a column is blown away, the structure has to be dimensioned in such a way that it doesn’t collapse.
He went on: “I am not against the use of wood in the project. However, I will not recommend the use of wood as carrying element in areas that could be exposed to severe loads. This includes both primary and secondary carrying elements like facades and glass interiors. This is due to today’s lacking knowledge about the properties of wood exposed to gunfire, impact and explosions. Considerable research and development work is needed before wood can become a protective material. The planning process for the new government building complex is at a stage where it is unlikely that there is time to wait for new research projects.”
“Everybody drives cars”
At the end of his presentation, Professor Langseth pointed to the proponents’ wish for environmentally friendly solutions as an argument for wood instead of steel and concrete.
“It puzzles me that you don’t mention aluminium. The material is Norwegian, produced with Norwegian hydroelectricity and we have Norwegian, world-leading expertise on the use of the material in protective structures and glass facades. Aluminium is light and has just as good energy-absorbing properties as steel. Everybody drives cars. They contain a lot of aluminium that tackles the loads from an impact,” he pointed out.
Langseth was the only scientist to appear before the parliamentarians. He was summoned in his capacity as head of the SIMLab research group at NTNU; world leaders in the design of crashworthy and protective structures. This position is confirmed by Professor Langseth’s decade-long editorship in the Journal of Impact Engineering.
The main presentation was given by a representative from the Norwegian Defence Estates Agency. They have a key role in the security aspects of the planning. The rest of the speakers represented interest groups and businesses from the wood, concrete, steel and aluminium industry as well as environmentalists and consulting engineers.
Happy to do research on wood
In the following question round from the parliamentarians, Professor Langseth was asked how much time would be needed to perform a research project on the protective qualities of wood.
He warned against such a project linked to the government building complex, since it would probably take ten years to get the necessary answers needed for projecting and design purposes.
On the other hand, he argued that it is a public responsibility to secure research and education within the field of public infrastructure security.
“…and I am happy to challenge you as parliamentarians to finance a large research project on wood. We happily take on the responsibility to lead the project, no problem,” he summed up.
Vote in May
The hearing was organized by the Standing Committee on Local Government and Public Administration. 3 May is the committee’s proposal deadline, with the Parliament debate set for 14 May.