The £3 million Akkerwinde bridge, boasting a span of 150ft and a rise of more than 50ft, will now serve as an elegant gateway in to the city of Sneek, Netherlands.
The bridge will support traffic to a weight of100 tons on a daily basis when it opens early in 2009, making it one of the few wooden heavy traffic road bridges anywhere in the world today.
The innovative project was completed by Titan Wood Ltd, who produce and supply Accoya® wood. The company has signed an exclusive option with BSW Timber to be the sole supplier of Accoya® wood in the UK and Ireland.
Titan Wood worked closely with designers OAK Architects to create the dramatic wooden bridge structure. Accoya® wood was selected because of its high strength-to-weight ratio, enhanced durability and dimensional stability and non-toxic qualities.
Another key reason for choosing Accoya® wood was because of its long service life. The Dutch Government has a requirement that all bridges must have a minimum service life of 80 years and invested £300,000 in independent testing of Accoya® to ensure it met the structural requirements and permitted a minimum design life of 80 years.
Finlay Morrison, CEO of Titan Wood, said: “Accoya® wood represents a new era in building technology. We are taking a traditional building material and using it in new and innovative ways. Accoya® wood, a green product through and through, allows builders and architects to think out of the box, while at the same time doing their part for the environment.”
John Alexander, head of business development at BSW Timber, said: “This project is a significant demonstration of the application of Accoya® wood in modern day use. An 80 year design life for an uncovered bridge would not be possible in any other timber.
“While the window door and cladding markets remain core in the UK, we are working on some large scale, challenging projects in a number of countries, including the UK. We are confident Accoya® wood’s performance will match the clients high expectations and create strong references for modern timber use.”
Timber Engineering Specialist Andrew Lawrence, from Arup, recently completed a study on the revival of timber bridges in Europe and the United States. Andrew supports BSW Timber’s claims that the use of timber in bridges will continue to increase in popularity, particularly in footbridges and low volume road bridges.
Talking about Akkerwinde Bridge, Andrew said: “Modified timber, such as Accoya® wood has proven to be very stable and more decay resistant than the best tropical hardwoods, which makes it an ideal choice for external structures such as bridges.
“In the past Accoya® has mainly been used for high value joinery applications, but at Sneek, a key architectural driver was the potential to fully expose the timber without protective cladding. With the increasing restrictions on the use of preservatives, acetylated timber provides a viable non-toxic alternative to the combination of untreated timber and expensive physical protection, that is now favoured in Germany.”
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