Use of modified wood enables Dutch bridge builders to dispense with protective cladding

The world’s first road bridge to be made out of the modified wood Accoya is now in place and ready to open early next year. The 50m-span bridge provides the gateway into the city of Sneek in the Netherlands and can support loads of up to 100 tonnes.

Titan Wood produced and supplied the timber on the project, which undergoes a modification process that improves the wood’s dimensional stability and reduces maintenance.

One of the key reasons for choosing Accoya was the Dutch government’s requirement that all bridges must have a minimum service life of 80 years, and it invested £300,000 in independent testing to ensure it met these requirements.

Timber engineering specialist Andrew Lawrence, from Arup, who recently completed a study on the revival of timber bridges in Europe and the US, said: “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.”