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Rapid Impact Compaction Rig in operation at National Ice Centre, Sheffield

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As part of the regeneration of the former steelworks area of Attercliffe the Sheffield City Trust proposed the construction of the National Ice Centre, to become a venue for training and competitive ice sports. Prior to this development the steelworks had been demolished leaving old basement areas backfilled with up to 2.5 metres of demolition rubble fill. The consulting engineer, Building Design Partnership sought to use ground improvement to provide 50kN/m2 bearing capacity for the new complex. Pennine proposed the use of rapid impact compaction that was considerably cheaper than the use of vibro stone columns. DesigDesigDesigDesign Solutionn Solutionn Solutionn Solution

The total area of ground to treat was some 8,640m2 which required two passes to achieve the compaction, each imprint receiving

20 blows from a 7 tonne hammer falling 1 metre onto a 1500mm diameter plate. Working for main contractor HBG Construction North East Ltd. the work was completed in 12 shifts. Compaction checks along with 10 plate load tests demonstrated that the required bearing had been provided. The works were completed in May 2002 enabling the foundations to be constructed without any excavation to the natural firm clay deposits. Rapid impact compaction is an economic technique to improve the bearing capacity of granular material to depths of up to 3-4 metres; it is unique to Pennine.