Considerable overload in relation to the bridge’s load influence and carrying capacity. – news Innlandet – Local news, TV and radio

The preliminary investigations support the hypothesis that Tretten Bru collapsed due to a break in one of the diagonals in the main span of the bridge. The capacity on the diagonals was half of what it should have been when the bridge collapsed, writes the National Accident Investigation Board in a new preliminary report. Whether the capacity has been reduced as a result of repeated loads or exhaustion, the Accident Investigation Board will try to clarify in the further investigations. Technical investigations have not revealed any signs of a reduction in the bridge’s load-bearing capacity as a result of rot or corrosion. Many hypotheses The Accident Investigation Board writes that it has been difficult to uncover the technical causal factors for the bridge collapse. The specialist group has worked its way through several hypotheses in order to rule out fracture mechanisms that are not relevant. There was significant consequential damage to the bridge structure, both from the collapse itself, from the impact with the ground and from the salvage work, and it has been challenging to separate these from each other, writes the commission. COLLAPSE: Thirteen bridges collapsed on 15 August this year. Two vehicles were on the bridge, but no one was injured. Photo: SHK



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