Parking of cars requires as open space as possible. This leads to structures with long spans and columns as vertical structures. Together these mean high concentrated loads to foundations.
With SSAB’s high strength S550J2H steel grade the design resistances of piles can be higher than with standard S460MH steel grade. This offers possibility to use smaller pile sizes and/or to reduce amount of piles. In Kupittaan Parkki case the resistance offered by high strength steel was fully utilized.
Three pile sizes RR140/10, RR270/12.5 and RR320/12.5 (S550J2H) were used in the project. RR140/10 piles were installed with hydraulic ram and larger piles were installed with 7 ton hydraulic hammer. 7 ton hammer was used to enable PDA testing with same driving equipment. RR320/12.5 pile size made of S550J2H steel grade was used in places with highest concentrated loads.
All piles were driven against the bedrock and the resistances of the piles were verified with PDA measurements in the beginning of the work. Totally 16 piles (5 pcs of RR140/10, 3 pcs of RR270/12.5 and 8 pcs of RR320/12.5) were installed to different locations around the building site and tested with PDA. All these test piles are also working as part of the final piling.