Wooden sheet piles more than meet design life

Research conducted by engineering firm Westenberg, commissioned by Centrum Hout and the Ministry of Agriculture, Nature and Food Quality (LNV) shows that in practice, wooden sheet pile walls made of wood with a durability class 1 achieve an average lifespan that far exceeds the design lifespan of 30 years.

It is already common knowledge that wooden sheet pile walls and shoring are climate-friendly and circularly applicable, CO₂ capture and also score favorably in terms of environmental impact. However, there is much discussion in practice about the service life of wooden sheet pile walls. A study was therefore commissioned by the Timber/VVNH Center and financed by the Ministry of Agriculture, Nature and Food Quality as part of the Policy Supporting Research theme 'Climate Envelope Climate Smart Forest, Nature and Timber'. The purpose of the study was to determine the life span in practice and to look at opportunities for wood innovation.

Based on 2390 projects, whose age is known and with a combined length of over 445 kilometers, an analysis of the underlying files was done and based on a selection of recent and reliable datasets (2015 - 2019) the average lifespan was determined. The conclusion is that sheet pile walls and shoring made of wood species with a natural durability class 1 (NEN-EN 335) have an average lifespan of 36.6 years. This is well above the design life of 30 years required by many clients. This also demonstrates that the lifespan of 25 years that is popularly talked about must be adjusted upward.

The study also looked at the factors that affect service life: a significantly longer service life can be achieved with good detailing and the application of a cover gap it was determined. This increases the lifespan to an average age of 43 years. Geographical position, soil type and water quality do not seem to have a significant influence on service life. Further research is needed on the influence of green space maintenance because this information is not sufficiently part of the reporting in current regular maintenance inspections.

By paying more attention to wood innovation and wood species combinations, an increase in the use of native wood is possible, Center Wood expects.

Learn more about sheet piling and other wood applications in civil engineering at:www.houtindegww.nl.