Buildings are sinking more than expected

Buildings are sinking more than expected

Top image: Pavel Kotov (t.v.) and Anatoly Sinitsyn at Unis Guest House, one of the two buildings they have measured the movements of for the past two years. They are surprised at how much the buildings have sunken in such a short time. Photo: Christopher Engås/Svalbardposten.

Researchers began measuring how much buildings in Svalbard are moving two years ago. Already they are seeing surprising results. We’re sinking.

28 August 2019
Text: Christopher Engås, Svalbardposten.

– After only two years, we see quite a large impact, especially in Longyearbyen. This can at least partly be attributed to climate change, says Anatoly Sinitsyn from Sintef. He is a civil engineer specializing in geotechnics and a former PhD candidate at UNIS.

Workshop
The project, called MonArc (Monitoring of Arctic Infrastructure), was started in 2017. It is a collaborative project between the University Centre in Svalbard (Unis), the State University of Moscow, and Sintef. Other supporters are Longyearbyen local community council, Trust Arktikugol and Store Norske Spitsbergen Grubekompani (SNSK).

In mid-August a small workshop was organized, in which Sinitsyn and his partner from the University of Moscow, Pavel Kotov, presented preliminary results.

– When we started the project we thought it would take five to ten years before we could discuss results, but we already see that it is possible to talk a little about the findings that have been made, says Sinitsyn.

Reference in the pipe
The measurements take place in Svea, Barentsburg, Pyramiden and Longyearbyen. In each settlement, the researchers have found a reference point, or zero point if you wish. The reference should be connected to bedrock. For Longyearbyen, two points used by the Norwegian Geological Survey (NGU) have been established at the bottom of the pipeline to the power plant.

Measuring with reference in the sea is not possible. Arne Aalberg, UNIS professor of Arctic infrastructure, who also participates in the MonArc project, explains why.

– If we had measured in relation to the sea level, we would have found that the buildings are rising. That’s because Svalbard is still rising quite a bit after the last ice age, he says.

Professor Arne Aalberg at Unis cannot say with certainty that the sinking is due to climate, but says that warmer climate does not help. Photo: Christopher Engås/Svalbardposten.

Old and new
MonArc has selected individual buildings in each settlement in which they measure the movements. This is done by fixing bolts in the columns, and then measuring the movements over time in relation to the reference heights. In Longyearbyen, the project has selected Unis Guest House (UGH) and The Vault hotel.

– We wanted a new building and an old one, to compare the two, says Sinitsyn.

In Svea, the measurements have been carried out on «The Barn» and Magnetite storage, and in Barentsburg and Pyramiden the researchers have measured the movements of relatively old buildings.

– Surprisingly high
That buildings are sinking in Svalbard is not new. Buildings are expected to sink quite a bit when they are new, then gradually decreasing.

– During the life of a building, which is designed for 35 years, it should sink from 50 to 100 millimeters. That means from 1.5 to 3 mm a year, says Sinitsyn.

What has happened in the past year is that UHG in Longyearbyen has sunk by about 8 mm at six of the 18 measurement points. On average, the building sinks by close to four mm a year. For The Vault, a new building where one could expect high values, it is less dramatic. The building has sunk by about 3 mm at three of the eight measurement points.

– The values are surprisingly high, and we believe that some of this can be related to the fact that it has become warmer, says Anatoly Sinitsyn.

Poor maintenance
The results in the other settlements in Svalbard are mostly less dramatic than in Longyearbyen. By comparison, “Complex GRZ” in Barentsburg has sunk by about one millimeter in the past year. In Svea, which is about to be dismantled, the barn has sunk by more than four millimeters at most, but far less elsewhere. The “record measurement” for the last year has Magnetite warehouse, which in one place has sunk by over 14 millimeters.

In Pyramiden, some major impacts have been recorded, but the researchers believe this can be explained by things other than permafrost that melts.

– Both in Barentsburg and Pyramiden, the lack of maintenance of buildings must be attributed to some of the reasons. These are drainage problems and, for Pyramiden, hot water leakage to the ground, says Pavel Kotov.

Climate or not
One thing is to note that buildings are sinking more than expected in Longyearbyen. Another thing is to ascertain what is the cause of this development. For Professor Arne Aalberg, the answer is not obvious.

– We do not know if this development would have happened anyway. But we know that the climate is changing. It gets warmer, and it doesn’t help the least, says Aalberg.

He emphasises that the permafrost in Svalbard can be hundreds of meters thick, and that since the 1980s we have seen that the active layer only has become ten centimeters thicker.

– It will take thousands of years for the permafrost to disappear. But that being said, ten centimeters of active layer can mean something for buildings and other infrastructure, he says.

Anatoly Sinitsyn shows the reference point for the measurements, at the bottom of the pipe at the power plant. Photo: Christopher Engås/Svalbardposten.

More expensive to build
Property Manager at SNSK, Karl-Eric Melander, boasts of the work done in  MonArc and thinks the results are interesting. He believes it must be built differently in the future.

– The fact that buildings in Longyearbyen are sinking so much means that we have to think again when making decisions about future construction activity. We have to pile deeper, and we can no longer use wood, but use steel. This, combined with new requirements for buildings in general, will mean that it will be considerably more expensive to build, he says.

Arne Aalberg agrees with Melander, and he believes rot in wood piles is one of the biggest threats to today’s settlement. The fact that we get rot in timber to a much greater extent is a direct consequence of the fact that it has become warmer.

The MonArc project continues for years to come. Anatoly Sinitsyn and Pavel Kotov look forward to taking new measurements in a few years, to see if the trend of sinking buildings continues at the same pace as now.

Contact person:
Anatoly Sinitsyn, anatoly.sinitsyn@sintef.no

This article was first published in Svalbardposten on 8 August 2019.

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