Solid background for Moss airport Rygge

Moss airport Rygge has opened for the public after almost ten years project work. The ground conditions in the area are considered as very difficult, but NGI's engagement has contributed to a safe and stable foundation for the airport.

Moss Airport Rygge, terminalbuilding. Photo Hille-Melbye

The ground conditions were one of the many challenges that had to be phased before the company "Rygge Sivile Lufthavn AS" (RSL) could start the construction of the new airport.

The geology of the Rygge airport area basically consists of layers of very soft clay 10 to 15 m thick which are also covered with 2 to 3m of swamp. NGi's responsible for the project Kyrre Emaus and Håkon Heyerdal describe the project as both difficult and challenging in construction terms. 

The consolidation of the highly compressible soft clay   masses was required. Vertical drains are placed (see   the network of short " pegs" sticking up) before   ruptured rocks are being loaded.

Feasibility studies and project management
RSL is a private company that was established in 1999 in order to study, plan, construct and run a civil airport. NGI was engaged at an early stage to conduct ground investigations for the whole project and to perform a feasibility study based on building principles.

RSL has also engaged NGI for project management of the outdoor areas while the main airport contactor Skanska AS has asked NGI to contribute in the planning of the terminal building and parking garage.

Huge savings
During this project work, NGI has focused to find cost effective and technical good solutions. Since the airport's main areas lye on very compressible soft clay and the deformation limits for this type of construction as very strict, this could result in either excavation of these soft clay deposits and their replacement with other light masses, or use of cement piles.

Instead of this solution, NGI suggested that these soft clay deposits could be consolidated by using hard rock blasted stones/debris as preloading, while creating vertical drainage paths in the clay. This alternative gave good results. NGI's project leaders inform that large amounts of blasted stones/debris were transported into the airport area and they were laid on the future take off and landing air stripe as well as on the rest of the airport area.  We then installed a series of transducers to measure subsidence and we organize the whole process.

Preloading the soft clay deposits with blasted stones/   debris and creation of vertical drainage paths in the   clay implicate that almost all expected subsidence   occur during the construction period and improve the   deformation (stiffness) behaviour of the clay.

After a period of about five to six months, this preloading stage had caused subsidence of about 80 to 90 cm, which implicated that the airport area was ready for the next construction step.

Stable and cost effectiveness
NGI's pre ground investigations showed also that the excavation and foundation of the terminal building had to be done with cement piles in order to secure the stability and bearing capacity of the future construction. The parking garage was founded on concrete piles that were driven to a depth of between 10 and 17 m until they reached bedrock.

The result of this project is that a cost effective and stable geotechnical solution has been applied at the Moss Airport Rygge and it was opened to the public in October 2007.

The airline company Norwegian operates 14 different routes from this new airport. In addition to that there a couple of other charter destinations to Gran Canaria in Spain and Antalya in Turkey.