Skjeggestad bridge got a serious blow Monday afternoon. It was at 15 o’clock that bridge simply collapsed, after the soil under the bridge crumbled and drew one of the poles that held up the bridge. Now it turns out that more bridges are in danger of meeting the same fate.
– We have much unstable due here in Norway, so it is nothing unusual that we build bridges on clay, says Borre Stenvold , brodirektør NPRA.
Now jobs Roads feverishly to create an overview of the bridges in Norway that are built on or near mapped clay.
– There are over 17,000 bridges in Norway, said Stenvold. It is enough a large number of which are built on clay.
Even more avalanche prone
A few kilometers south of Holmestrand is Helland Bridge. A bridge that has frightening much in common with the one that collapsed Monday afternoon. Here goes E18 over an area which according NVE mapping is even more susceptible to quick clay slides than the bridge at Holmestrand was. This can brodirektør Stenvold confirm.
– Yes, here we are talking about two bridges that go over or closely related areas that are prone to quick clay slides.
– Will have consequences
Skjeggestad bridge consisted final inspection with flying colors. It was in 2011, when there was nothing wrong with either the framework or scratch around. Helland bridge is constructed in the same manner as Skjeggestad bridge, partly on mountain, partly steel core pillars drilled in the rock. What will happen if the areas under one of the bridges breeds like?
– No, it could indicate that a strain similar to that occurred during soil slide at Holmestrand will get other bridges to crack together, says press officer Roads, Kjell Bjørn Vinje.
He says Director of Roads has asked the regions to take an additional check on the bridges are constructed the same reason as Skjeggestad bridge. Currently they do not know exactly what caused the bridge collapsed, thus it is difficult to say what measures should be taken.
But Vinje states that what happened is going to have consequences for the further management.
– This did not happen, so we turn every stone to find out why it happened, so that we can prevent it from happening again.
On Tuesday afternoon, VG published an article on the 237 bridges in Norway damage or defects that threaten the carrying capacity. VG has disclosed overview of NPRA.
Vinje believes VG case can not be seen in the context of brokollapsen in Vestfold.
– We have registered VG view based on our own numbers. This is an overview showing Norwegian bridges with reduced capacity and thus have nothing with brokollapsen Vestfold to do. It was not detected any errors and omissions on Skjeggestad bridge before the event, and there are indications that there was no reason for the collapse broteknisk says Vinje.
Can race without notice
Inger -Lisa Solberg is a researcher at the Geological Surveys. She researches much on clay landslide and has been involved in mapping such clay areas located around Helland Bridge.
– Quick camp is fixed until load is so great that it breeds out. When the liquid, almost like water.
It is not so nimble camp is in constant motion, like a river under the ground. Conversely, Solberg tell that shake propagated well in clay and thus feels good. It does not mean that the camp is about to race out. It happens only when the load is large enough.
– It is not certain that you get much notice. Perhaps one can observe some cracks as before, but it is not certain.
She says that there are clay in the country, but that including large parts of eastern Norway are very vulnerable.
Minister promises money
Transport Minister Ketil Solvik-Olsen (FRP) was on inspection by Skjeggestad bridge Tuesday afternoon.
He promised that stretch of road to be opened as quickly as possible and that it should not be for the money to get organized on the local traffic problems.
– If there is no damage to the northbound run on the bridge, it will quickly be able to be used as bypass, says Solvik-Olsen.
Several vehicles stood Tuesday evening still on the bridge, and construction manager Odd Tandberg Road Administration informs NTB that it is not yet clear when they can be retrieved.
Public Roads have experts in place to investigate the circumstances, and until they have had their say, happens little.
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