The reason Norwegian wooden bridges were closed was because they had no answer to the Dredden collapse. They will reopen soon – and the Norwegian Road Administration assures that it is completely safe.
The Norwegian Public Roads Administration told VG last week that they had made the choice Cover the other 14 wooden bridges They did not find the cause of thirteen declines after the first day.
They said on Saturday Reopening of bridges As of this week, though, the cause has not been discovered.
– Because closures cause problems for road users. There is a risk of accidents elsewhere, especially on bridges with heavy traffic. But we will not open other bridges if it is for safety reasons. Although we don’t know the specific reason at Tretten, Morten Raitt Hansen, division manager at the Norwegian Road Administration, tells VG.
VG is among others Previously written Detours cause major traffic problems and some minor accidents.
– While you can’t find the cause at Treton, could there be something wrong with other bridges that haven’t been discovered in the current study?
– There is a lot to be done, and now they should have examined it very thoroughly, if they do not find anything now, then the bridge is in the position as it should be according to the drawings and calculations.
– Thirteen people have done ten studies in seven years. Not enough studies in Tretten?
– When we don’t know the cause of the decline, we can’t answer that question. Again this is something for the Accident Investigation Board to find out and they will be looking at a number of aspects.
– The interesting thing about thirteen is that we need to identify one or more causes and modify the controls.
Now the inspection rules have been tightened
– Can there be changes in inspection rules?
– This may be something that you need to pay particular attention to in the supervisor, and then we will consider it. It can be both when it comes to exploration and dimension.
The Hansen study allows changes to the rules:
– This can be a guide to bridge inspections specifically with guidelines for what you should pay particular attention to. We will also evaluate design rules for bridges when the report is available.
Project planning is the calculation of a bridge to withstand the forces acting on it and the construction of the foundation to be followed during the construction of the bridge. This can be drawings or computer-aided modeling (BIM).
Hansen hopes the results of the tests could come as soon as Monday. This will determine which bridges are ready to open. So not all bridges will open at the same time.
read more: 9 Principles of Thirteen
The task of checking other bridges is two-fold, the division manager explains: One part has to go through “paper work” – how much load the bridge has carried before, when it was built, according to which standards the bridge was dimensioned. This part of the survey is ready.
The second part is the physical examination of the bridge. They went over several points which you can see in the fact box below.
Hansen uses the Maumbeken Bridge in Friedrichstadt as an example of how they assess it: the bridge carries loads of up to 400 tonnes.
– So if we don’t see the usual damage on that bridge, there’s no reason to close it.
This is where they think there is a mistake
When bridges are opened, there are restrictions on use for safety reasons, for example, light regulation or a limited number of lanes. More frequent surveys will be considered.
In a press release sent out by the National Roads Administration on Saturday, they wrote that while they are not sure why Tretton collapsed, they do know the mechanisms and weaknesses that caused it to happen.
– What are the mechanisms and weaknesses?
– That’s what’s on the list in the press release, we’re looking for nodes and junctions and distortions. We think the error may have disappeared.
– So you don’t have a clue, but use “engineering logic”?
– Yes, it is engineering logic that we assess where the bridge might weaken. I don’t think the answer can be found anywhere other than the listed points.
– We have been unable to ascertain anything further as to the cause of the collapse of Tretton Bridge. We are working with 14 others and thirteen are being fully investigated by an external team led by the Accident Investigation Board. But if they find something now, they will continue to let us know, I’m sure.
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