PERFORMANCE OF A SWAGE PILE/SLEEVE CONNECTION WHEN SUBJECTED TO CYCLIC LOADING

The swage pile connection system has been available for some 10 years for application to subsea structures and jackets. More recently designed offshore structures including lightweight jackets, TLP's and compliant towers, particularly in deep water, require foundations that are designed to withstand extensive cyclic loading. Due to the interest in swage pile/sleeve connections a project has been funded by a number of major oil companies and the UK Department of Energy to investigate the performance under this type of loading. The paper describes the testing undertaken on 5.25" and 16.0" model piles. The tests consisted of axial and bending tests both "in air" and "in seawater" conducted under various loading conditions including uni-directional and through zero. The results are presented in the standard stress-endurance format and compared with the "F2", "F" and "C" design classifications for weldment tubulars. The conclusion reached is that, within the test parameters of the project, fatigue related damage is not a problem. Completion of the programme has satisfied the project participants as to suitability of the swage pile/sleeve connection for application to fatigue dominated structures.