Use of structural simulation for extension of life of offshore structures

The extension of life, or the change of use of offshore structures requires re-assessment of their capacity to carry the specified loads, which may have changed from the original design premise. The paper presents the methodology of using non-linear finite element analysis to simulate the limit states of response of a large offshore structural component to the imposed loads. The work described here was initiated when linear analysis coupled with code check formulations showed that a significant degree of strengthening would be apparently required to enable the structure to function satisfactorily. However, structural non-linear simulation combined with a limit state assessment method proved conclusively the strengthening to be unnecessary, thus eliminating costly offshore fabrication and reducing shut-down time.