By Frank Rausche, Goble and Associates
This paper was first publsihed in GE’s May 1980 issue.
This paper was first presented (as paper EUR 51) at the European Offshore Petroleum Conference held in London in October last year and is published here by kind permission of the organisers. It is the sixth and final paper in the series on the Heather platform piling, the first two having been published in GE’s November 1979 issue, the third, fourth and fifth in January, March and April 1980, respectively.
The first leg piles of the Heather platform were instrumented using strain transducers and accelerometers that were attached to the pile just below its top. The signals were processed in real time providing for a hammer blow a printed output of hammer energy in the pile, maximum pile top force and other quantities. The signals were also recorded on analogue magnetic tape.
A detailed analysis was performed in the laboratory on a digital computer. Using wave equation type pile and soil models and both force and acceleration data, the soil resistance distribution was determined.
The Heather platform piles were driven through two followers connected by gravity. Stress wave effects from the connectors were studied and ‘losses to the impact wave were determined.