As you drive through Tretten, you see a temporary steel bridge over the river Gudbrandsdalslågen. There used to be an award-winning wooden bridge here. It collapsed on 15 August 2022, after only ten years in service.
The bridge was designed to last 100 years. It was a unique construction - a combination of glued laminated timber and steel that had never been built anywhere else in the world. The investigators later concluded that the designers focused too heavily on aesthetics. They also used older building regulations that did not account for a type of structural failure called block shear. When a 48-tonne truck drove onto the bridge that Monday morning, the whole thing broke apart and fell into the river.
This was actually the second timber bridge collapse in six years. In February 2016, a similar bridge at Perkolo near Sjoa had collapsed when a truck crossed it. After that incident, the Road Administration inspected similar bridges - including Tretten - and found "serious faults." They recommended strengthening. But nothing was done. The official investigation later called this "a system failure."
Two vehicles were on the bridge when it collapsed. The car plunged into the water - the driver managed to free himself. The truck ended up nearly vertical, stuck on a section rising steeply from the river. The driver, Terje Brenden, sat in his cab for an hour before a rescue helicopter lifted him out. Miraculously, no one was seriously injured.
The day after the collapse, Norway closed 14 wooden truss bridges across the country. Eight were in Viken county, five in Innlandet, and one in Nordland. Most had been built after 2000. As of early 2024, nine of these bridges remained closed or restricted, and four are being rebuilt. The consequences for timber bridge construction in Norway have been significant - future designs now emphasise resilience, updated safety standards, and hybrid construction methods.
The collapse split the Tretten community in two. Residents on the west side suddenly faced 22 kilometre detours. Some took boats across the river to get to work. Children had 40-minute bus rides to school. It took almost a year to build a replacement.
When the new temporary bridge opened on 30 June 2023, there was one obvious choice for who should drive across first. Terje Brenden, in the same truck that had been stuck on the collapsed bridge, was given the honour. He called it "a form of therapy." He also mentioned he had avoided all wooden bridges since the accident. The new bridge is made of steel.
A permanent replacement is planned for 2028. The total cost - cleanup, temporary bridge, and permanent replacement - will be around 420 million kroner.