I am still looking for thirteen answers – still more bridges can be opened – VG

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The Norwegian public roads administration told VG last week that it had chosen to do so close the other 14 wooden bridges when they did not find the cause of the collapse of the Thirteen after the first day.

Saturday they stated that them at work to reopen the bridges per week, even if the cause has not been found.

– It is because closures cause problems for road users. Especially on the busiest bridges, the risk of accidents elsewhere increases. But we will not open other bridges if at the expense of security. Although we do not know the specific cause in Tretten, Section Manager Morten Wright Hansen of the Norwegian Road Administration tells VG.

VG has, among other things previously written that detours cause serious traffic problems and some minor accidents.

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– When you haven’t found the reason on Tretten, could there be something wrong with other bridges that haven’t been found in the inspection now?

– There is a lot to do, now they must have inspected so thoroughly that if they find nothing now, the bridge is in the condition it should be according to the drawings and calculations.

– Thirteen have had ten inspections in seven years. So the inspections in Tretten weren’t thorough enough?

– When we do not know the cause of the collapse, it is impossible to answer this question. Again this is something the Accident Investigation Board needs to find out, it will look into many different aspects.

– The interesting thing about the thirteen is if we find one or more reasons why we need to intervene and change the regulations.

Currently tightening of inspection rules

– Can there be changes to the inspection rules?

– It could be, especially in the supervisor with things you need to pay special attention to, so we have to consider it. It can be both when it comes to inspection and sizing.

Hansen allows changes to the inspection rules:

– It can be, especially in the bridge inspection guide with guidelines for what you need to pay special attention to. We will also evaluate the design rules for bridges when the report becomes available.

Design means calculating a bridge so that it can withstand the forces acting on it and create a foundation that must be followed when building the bridge. They can be computerized designs or models (BIM).

Hansen believes the inspection results can arrive on Monday. Therefore, he will decide which bridges are ready for opening. Therefore, all bridges will not open at the same time.

Read also: 9 out of thirteen theories

The work to check the other decks was twofold, explains the head of the section: one part was to go through the “paperwork”: how much load did the bridge endure before, when was it built and according to what standards it is the bridge was dimensioned. This part of the survey is ready.

The second part is the physical inspection of the bridge. So they looked at several points that you can see in the fact box below.

Hansen uses the Moumbekken Bridge in Fredrikstad as an example of how they rate: this bridge has had many heavy loads, up to 400 tons.

– So if we don’t find typical damage on that bridge, we see no reason to close it.

This is where they think the fault is

When the bridges are opened, it may still happen that, for safety reasons, there are restrictions on use, for example through dimming, or a reduced number of lanes. More frequent inspections will also be considered.

In the press release released Saturday by the National Road Administration, they write that, while they don’t really know why Tretten collapsed, they do know the mechanisms and weaknesses that may have contributed to this.

– What mechanisms and weaknesses?

– This is what’s listed in the press release, we’re looking for knots and joints and warps. This is where we think the mistake may be hiding.

– So you have no clues, but you use “engineering logic”?

– Yes, it is the engineering logic in which we evaluate where the bridge could be weakened. I don’t think the answer can be found anywhere other than the points listed.

– We haven’t found anything else about the cause of the collapse of the Tretten Bridge. We are working with the other 14 and Thirteen are being thoroughly investigated by an outside group led by the Accident Investigation Board. But if they find something now they will inform us all the time, I’m sure.

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