Reports Show Security Measures In Place – NRK Oslo and Viken – Local News, TV and Radio

NGI is now publishing reports on ground investigations, geotechnical assessments and safety measures in the landslide area at Gjerdrum for the past 20 years.

– NGI has had a role here, among other things with the planning of this housing area that has been taken over by the avalanche, NGI CEO Lars Andresen tells NRK.

– In 2003 it was well known that this area had fast clay. In these areas, special requirements and special considerations are established for planning and construction work.

Three types of security measures

Three security measures are described in the reports that NGI has:

• Terrain relief, so that weight is reduced in the direction of a possible landslide
• Fill the weight into the lower ground of the ravine valley, be sure to establish infills that will act as a counterweight to a possible landslide.
• Protection against erosion of the creek that runs to the bottom of the valley

Andresen tells NRK that they have reason to believe that security measures have been met.

– But we don’t have any concrete documentation in this regard. The measures and their monitoring are described in detail in subsequent reports.

– We know from previous experience that landslides occur. Exactly what has triggered this landslide are things to which we must return and to which we hope to get answers in the comprehensive review that we are now going to begin with.

– You have followed the guidelines

Gjerdrum Boligutvikling CEO Odd Sæther was instrumental when the development of the area started 15-20 years ago. Later, several measures had to be taken due to the difficult terrain conditions.

– I’m not a geotechnician, but we’ve relied on Ask for 30 years. When building on clay, you should include a geotechnician and a geologist. NGI has been behind and been a leader in the polls of the various masses, and we have followed their lead, Sæther tells NRK.

Sæther lives in Ask and is one of the evacuees from Gjerdrum.