SSAB delivered 5 700 meters of pile pipes and pile elements to the foundations of Kirkebakken apartment buildings in Norway. RR270 and RR320 piles were upgraded to high strength steel S550J2H RRs piles to keep high load capacity after corrosion is taken into account in the top of the piles. By using the higher steel grade S550J2H, pile’s load-bearing capacity can be added by 25 % over that of traditional RR piles. Delivery included 1 176 meters of RRs270/12.5 and 1380 meters of RRs320/12.5. RR220/10 piles were delivered as pile elements with external sleeve splice. Ready-made pile elements enable quick and cost-effective splicing with no welding of the splice needed on site. Total amount of pile elements was 3 168 meters. All piles and pile elements were 12 meters of length.

Figure 1. High strength steel RRs piles and ready-made pile elements enabled good and cost-effective solution for the project.

Piles were first driven through hard moraine of 12 meters and then through silt and clay layers. Piles stopped in moraine after 70 meters. The tendered length of piles was 55 meters, so the project expanded roughly by 30%. The challenge for the customer was the expected excess pore pressure caused by the installation of the piles.

Piling contractor Nordisk Fundamentering AS was satisfied with the delivery and product. “Delivery was quick and reliable. RR220 elements were very easy and fast to install, no welding needed.” says Kai Tiller, Nordisk Fundamentering AS. Contractor of Kirkebakken is Tronrud Bygg AS and project owner is Boligutvikling Frogner AS.

Figure 2. Piling contractor Nordisk Fundamentering AS installed 5.7 kilometers of piles and pile elements.

Kirkebakken is located in Frogner in Sørum municipality, which is situated in south-east part of Norway. Kirkebakken includes 73 new apartments with walking distance to shops, bus and train connections.

Figure 3. Kirkebakken is located in south-east part of Norway. (Picture: