DEVELOPMENT OF A SWAGED PILE/SLEEVE CONNECTION SYSTEM FOR APPLICATION ON A NORTH SEA JACKET

The hydraulically swaged pile/sleeve connection system has gained general acceptance in the installation of subsea structures. Generally piling for such structures is of small diameter and loading levels are low. Nevertheless the simplicity and speed of operation of the swaged system has made it the preferred option and has created a significant interest in its potential for larger jacket structures. In early 1986 BP expressed an interest in using the technique on one of their Southern North Sea gas platforms. Since the loading requirements and scale of operation for a North Sea jacket installation were substantially greater than the then current state of the technology, this led to BP Exploration entering into a development programme together with the UK Department of Energy and BUE Hydra-lok. A programme was defined, with the aid of the relevant authorities which, when successfully completed would enable the system to be used as a large diameter pile/sleeve connection. The paper discusses the results of analysis and resting undertaken during the programme. The programme included cyclic testing, full scale 72" connection load testing, bending tests and load testing on multiple groove geometries. As a consequence of this testing and prior experience of the hydraulically swaged connection system, design criteria appropriate to a North Sea jacket installation have been defined. The swage pile connection system offers new opportunities in offshore installation avoiding many of the problems associated with the current techniques. Such techniques have in the past been extremely diver intensive, particularly with respect to contingency procedures, whereas swaging offers a totally surface controlled diverless alternative.