The Weekly Reflektion 36/2022

Having people that are competent to carry out their work and exercise their responsibilities is of course essential. Just as essential is ensuring that there are enough people with the full range of competencies needed for the work to be undertaken.

The Tretten bridge after it collapsed

Do you have the competence to ensure your structures are properly designed and appropriately maintained?

One of the materials that is currently making a ‘buzz’ in the construction world is ‘laminated timber’. The drive for renewables, reduction in the environment impact, and low carbon footprint constructions has made wood more attractive. Laminated timber is made from layers of wood bonded together with durable, moisture resistant structural adhesives.Wood has been used for construction since the dawn of civilisation so one would assume that the materials properties are well understood and considered in any design. Also, that the aging and degradation mechanisms are well known in order to establish an appropriate maintenance system. Proper design and appropriate maintenance are the foundations of structural integrity. It seems this assumption may not becorrect.  

On the morning of Monday 15th August, the Tretten bridge, in Gudbrandsdalen, Norway, collapsed. The main truss of the bridge was made of laminated timber. In 2016 another similar bridge, the Perkolo bridge, also in Gudbrandsdalen collapsed. The investigation into the Perkolo bridge collapse indicated a design fault that led to the joints in the bridge being significantly under-dimensioned and only tolerating 27% of the planned load capacity of 65 tons. 

The collapse of the Tretten bridge is currently being investigated by the Police and the Norwegian Safety Investigation Authority. It is our understanding that the State Highways Authority and the local council will carry out an independent investigation and that SINTEF, an independent research organisation in Norway, will be involved. There is an obvious temptation to connect the two incidents and ask the question on what was learned from the Perkolo bridge collapse and whether it was relevant and applied to the Trettenbridge. We don’t want to jump the gun here and will follow the investigations and cover any relevant and interesting points in future Reflektions.

It was however interesting to read two articles on the bridge collapse in Teknisk Ukeblad (TU), a monthly technical publication that we would recommend for anyone interested in engineering and technology. 

The State Highways Authority were responsible for the construction of many bridges in Norway and were acknowledged as world leaders in bridges using laminated timber. In 2015 an internal note was circulated warning of the loss of competence due to people leaving for better paid jobs in the private industry. In 2017 the bridge section of the State Highway Authorities issued an extensive report on experience with modern Norwegian wooden bridges. The report stated that the Authority did not really know how to maintain modern wooden bridges since they did not have much experience. Hardly a reassuring statement and certainly not to be expected of a competent Authority.

Later changes in roles and responsibilities for State controlled organisations led to the Regional Councils, who are responsible for operation and maintenance of the road system in Norway, also taking over responsibility for construction of roads and bridges. How competence will be assured was not covered in the TU article.

Do you make sure your people are competent and then make sure there are enough people to adequately cover the competencies you need?

Reflekt AS