Decommissioning of offshore piles using vibration

This paper reports on an investigation of the feasibility of decommissioning offshore tubular piles with vibration. A series of 1g model pile tests using a scaled vibration source and a 400mm long open-ended steel pile were conducted in loose and dense dry sand. Under forced vibration, the pull-out load of the pile was reduced by 36% in dense sand and to the self-weight of the pile in loose sand. Back-calculation reveals a correlation between the lower tensile capacity of the pile and reduced interface friction angles during the application of vibration indicating that such a method may be valuable in future decommissioning projects.