Norwegian government supporting and promoting the construction of timber bridges

Norwegian government supporting and promoting the construction of timber bridges

Norway has set a strong policy objective of significantly increasing the share of timber bridges in bridge construction. The share of timber bridges in Norway is currently about 10%, whilst in Finland it is estimated to be around 4%. Supporting the use of wood in bridge construction is part of the Norwegian government’s wood construction promotion programme.

Norway has set a strong policy objective of significantly increasing the share of timber bridges in bridge construction. The share of timber bridges in Norway is currently about 10%, whilst in Finland it is estimated to be around 4%. Supporting the use of wood in bridge construction is part of the Norwegian government’s wood construction promotion programme.

- In Norway, we have a strong political will to promote the use of wood including in bridge construction, says Otto Kleppe Director of Roads at the Norwegian Public Roads Administration. In the beginning, it was politicians who applied the pressure and, now that it has been possible to create a market, the State is directing funds to the research and development of bridge building and, more specifically, timber bridge building. We are also targeting export markets for timber bridges.

Development work is taking place in co-operation between the Public Roads Administration, Moelven a company specialised in wooden products and NTI, the Norwegian Institute of Wood Technology. Most timber bridges built in Norway are bridges for non-motorised and pedestrian traffic and at intersections, whilst about half a dozen large road bridges are built every year. The best-known large timber bridges are the Da Vinci Bridge, the Tynset Bride and the Rena Bridge.

- We’re pleased with the results of the bridge construction, because it is now a genuine alternative even for the construction of bridges for heavy motorised traffic. The longest timber bridge is currently 70 metres but technically it is possible to build one twice that length. Our need to build bridges in Norway is enormous. In the construction of each motorway, the bridges form a large cost item, says Kleppe.

Norway – site of the world’s longest timber bridge

At Lake Mjøsa in Norway, the world's longest timber bridge is being planned measuring 1,400 metres, and a popular movement has been created to ensure that it comes to pass. Through wood construction, there is a desire to strengthen the country’s image as a leading country in the field. The breakthrough for public wood construction took place at the Winter Olympic Games at Lillehammer in Norway in 1994, when many wooden venues were built. Wood construction was considered to have significant positive effects on the economy, aesthetics and the environment.

According to Kleppe, it is not set in advance where a timber bridge will be built, but rather local conditions dictate the choice. - We need different types of bridges for different sites and purposes. The key thing is that we have the will to develop timber bridges and to promote their use. Because Norway is a country of trees and wood is a renewable and ecological material, it’s particularly good for the public sector to send the message that we are prepared significantly to increase the use of wood in bridge construction.  

Timber bridges sufficiently competitive

Kleppe considers bridge construction to be technically challenging, because their joints are subject to great natural forces. - In bridge construction, you need a large hall in which industrial prefabrication is possible and an effective method of production. It must be possible for the bridge to be built first in the hall before it is ready to be transported to its final place of construction and reassembled.

Norway has developed a bridge solution that is particularly suitable for small bridges. In large bridges, each one requires its own individual solution. - In bridge construction there is still too little competition, although bridge structures from Central Europe are being imported, especially to Southern Norway. Finnish and Swedish companies are welcome to the Norwegian bridge-building market, says Kleppe.

According to Kleppe, the competitiveness of a timber bridge compared to steel and concrete is sufficient when compared as a basic solution. - Although architectural costs do increase the price, it endows the bridge with a certain aesthetic added value, which attracts attention in a simple way compared to concrete. Wood has done well in project competitions, because it has won in terms of overall costs.

Trying to replace creosote treatment with new solutions

- Wood is a renewable material, the promotion of the use of which also has many ecological justifications, says Kleppe.  Because we’re not interested in chemically-treated wood, we are trying to develop new solutions that are durable. Now we particularly need more information on the properties, possibilities and competitiveness of the use of wood in bridge construction.

 Kleppe thinks that it is a shame that the bridges on roads for forest vehicles have been made of concrete. - This shows that they are unaware of the existence of timber bridges. We go to Central Europe and are amazed at the long tradition there of timber bridges, but we have not done likewise even though we have our own raw material and processing expertise in Norway. From a point of view of employment and the economy, it's worth prioritising our own material and promoting the processing of raw timber into, for example, glulam.

In Norway, infrastructure construction is challenging. The country contains a total of 54,500 km of roads, and on top of this is the maintenance of thousands of ferry connections. The average age of bridges is calculated at 40 years. Their average length is 25 metres and total length 460 kilometres.  About €400 million is spent annually on bridge construction, which also includes ferry docks. This year, the Public Roads Administration was granted additional funds from the State budget to build 140-160 new bridges every year.

Article service/Markku Laukkanen
Additional information: Otto Kleppe, otto.kleppe@vegvesen.no